Non-invasive methods of measuring blood velocity, especially Doppler velocimetry, are being increasingly used in obstetrics to provide observational information. We report a preliminary study of their usefulness in experimental studies. Doppler velocimetry was used to assess blood flow and velocity-time profiles in the common carotid artery of seven women of reproductive age before and during the incremental administration of angiotensin II. Angiotensin II infusion evoked the expected increments in systolic and diastolic arterial pressure and fall in heart rate. Angiotensin II was associated with a dose-dependent fall in maximum blood velocity, which, at an average rise in systolic blood pressure of 23 mmHg, had fallen from 91 +/- 16 to 52 +/- 4 (mean +/- SD, p < 0.01). Absolute maximum blood velocity was strongly correlated with systolic and diastolic blood pressures (p < 0.001 for both). The minimum velocity was unaltered throughout, and the calculated flow did not change significantly (490 +/- 100 cf. 380 +/- 50 ml/min). Overall, these findings are in agreement with those previously reported using invasive methods of monitoring flow during angiotensin II infusion, and further support the usefulness of Doppler velocimetry as an investigative tool in human physiology and pharmacology.However, the pulsatility index, resistance index and systolic/diastolic velocity ratio all fell significantly during angiotensin II infusion (p < 0.01 for all). The conventional interpretation of a fall in these indices, i.e. reduced downstream resistance, is clearly erroneous under these circumstances, since angiotensin II induces arteriolar vasoconstriction. This illustrates the importance of interpretation of Doppler velocity envelopes in the light of pharmacological mechanisms likely to be evoked by the experimental procedure.
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http://dx.doi.org/10.1046/j.1469-0705.1991.01030171.x | DOI Listing |
Postgrad Med
January 2025
Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hypertension Institute, NHC Key Laboratory of Hypertension Clinical Research, Key Laboratory of Xinjiang Uygur Autonomous Region, Hypertension Research Laboratory, Xinjiang Clinical Medical Research Center for Hypertension (Cardio-Cerebrovascular) Diseases, Urumqi, China.
Purpose: Limited studies have examined the relationship between plasma aldosterone concentration (PAC) and arterial stiffness progression. This study aimed to investigate the longitudinal association between baseline PAC and arterial stiffness progression in hypertensive patients.
Patients And Methods: This was a longitudinal study conducted at the Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region between April 2020 and October 2023.
Am J Clin Nutr
January 2025
Department of Nutritional Sciences, Pennsylvania State University, University Park, PA, USA. Electronic address:
Background: The vascular and cardiometabolic effects of pecans are relatively under-studied.
Objectives: The aim was to examine how substitution of usual snack foods with 57 g/day of pecans affects vascular health, risk factors for cardiometabolic diseases and diet quality, compared to continuing usual intake in individuals at risk for cardiometabolic diseases.
Methods: A 12-week single-blinded, parallel, randomized controlled trial was conducted.
PLoS One
January 2025
Department of Physiology and Biochemistry, Faculty of Physical Education and Sport Science, Wroclaw University of Health and Sport Sciences, Wroclaw, Poland.
The purpose of this study was to determine the effective warm-up protocol using an added respiratory dead space (ARDS) 1200 ml volume mask to determine hypercapnic conditions, on the swimming velocity of the 50 m time trial front crawl. Eight male members of the university swimming team, aged 19-25, performed three different warm-up protocols: 1) standardized warm-up in water (WUCON); 2) hypercapnic warm-up in water (WUARDS); 3) hypercapnic a 20-minute transition phase on land, between warm-up in water and swimming test (RE-WUARDS). The three warm-up protocols were implemented in random order every 7th day.
View Article and Find Full Text PDFElectromagn Biol Med
January 2025
Department of Mathematics, University of Gour Banga, Malda, India.
In cardiovascular research, electromagnetic fields generated by Riga plates are utilized to study or manipulate blood flow dynamics, which is particularly crucial in developing treatments for conditions such as arterial plaque deposition and understanding blood behavior under varied flow conditions. This research predicts the flow patterns of blood enhanced with gold and maghemite nanoparticles (gold-maghemite/blood) in an electromagnetic microchannel influenced by Riga plates with a temperature gradient that decays exponentially, under sudden changes in pressure gradient. The flow modeling includes key physical influences like radiation heat emission and Darcy drag forces in porous media, with the flow mathematically represented through unsteady partial differential equations solved using the Laplace transform (LT) method.
View Article and Find Full Text PDFMalawi Med J
January 2025
Department of Paediatrics, College of Medicine, University of Nigeria Ituku/Ozalla and University of Nigeria Teaching Hospital Ituku/Ozalla, Enugu, Enugu State, Nigeria.
Background: Children with Tetralogy of Fallot (TOF) usually present with right heart abnormalities, however much is not known if these children presents with left ventricular dysfunction.
Objectives: This article is aimed to ascertain the left ventricular function of children with TOF compared with those without any congenital heart disease. It also elicits the correlation if any, between left ventricular mass and descending aorta blood flow.
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