MyMedR

Displaying all 6 publications

Abstract:

Sort:

Dependence of human forearm skin postocclusive reactive hyperemia on occlusion time

Tee GB, Rasool AH, Halim AS, Rahman AR

J Pharmacol Toxicol Methods, 2004 Jul-Aug;50(1):73-8.
PMID: 15233971 DOI: 10.1016/j.vascn.2004.02.002

Human postocclusive forearm skin reactive hyperemia is not only a potential means of identifying early signs of cardiovascular diseases, it can also be used in the assessment of local microvascular response to topically applied compounds on skin. The method is not fully characterized. In this study, we investigated the influence of occlusion time on postocclusive forearm skin reactive hyperemia using laser Doppler fluximetry (LDF).

Matched MeSH terms: Hyperemia/physiopathology*
Influence of stenosis on hemodynamic parameters in the realistic left coronary artery under hyperemic conditions

Kamangar S, Badruddin IA, Badarudin A, Nik-Ghazali N, Govindaraju K, Salman Ahmed NJ, et al.

Comput Methods Biomech Biomed Engin, 2017 Mar;20(4):365-372.
PMID: 27612619 DOI: 10.1080/10255842.2016.1233402

The current study investigates the hyperemic flow effects on heamodynamics parameters such as velocity, wall shear stress in 3D coronary artery models with and without stenosis. The hyperemic flow is used to evaluate the functional significance of stenosis in the current era. Patients CT scan data of having healthy and coronary artery disease was chosen for the reconstruction of 3D coronary artery models. The diseased 3D models of coronary artery shows a narrowing of >50% lumen area. Computational fluid dynamics was performed to simulate the hyperemic flow condition. The results showed that the recirculation zone was observed immediate to the stenosis and highest wall shear stress was observed across the stenosis. The decrease in pressure was found downstream to the stenosis as compared to the coronary artery without stenosis. Our analysis provides an insight into the distribution of wall shear stress and pressure drop, thus improving our understanding of hyperemic flow effect under both conditions.

Matched MeSH terms: Hyperemia/physiopathology*
Reproducibility of different laser Doppler fluximetry parameters of postocclusive reactive hyperemia in human forearm skin

Yvonne-Tee GB, Rasool AH, Halim AS, Rahman AR

J Pharmacol Toxicol Methods, 2005 Sep-Oct;52(2):286-92.
PMID: 16125628

Postocclusive reactive hyperemia in forearm skin is a commonly used model for studying microvascular reactivity function, particularly in the assessment of vascular effect of topically applied pharmacological substances. In this study, we investigated the reproducibility of several different laser-Doppler-derived parameters in the measurement of postocclusive reactive hyperemia at forearm skin in healthy subjects.

Matched MeSH terms: Hyperemia/physiopathology*
Determining weight-bearing tissue condition using peak reactive hyperemia response trend and ultrasonographic features: Implications for pressure ulcer prevention

Yapp JH, Raja Ahmad RMK, Mahmud R, Mohtarrudin N, Mohamad Yusof L, Abdul Rahim E, et al.

Wound Repair Regen, 2019 05;27(3):225-234.
PMID: 30667138 DOI: 10.1111/wrr.12698

Frequent repositioning is important to prevent pressure ulcer (PU) development, by relieving pressure and recovering damages on skin areas induced by repetitive loading. Although repositioning is the gold standard to prevent PU, there is currently no strategy for determining tissue condition under preventive approaches. In this study, the peak reactive hyperemia (RH) trends and ultrasonographic (US) features are compared with the tissue condition under histopathological examination to determine the potential use of these features in determining the tissue condition noninvasively. Twenty-one male Sprague-Dawley rats (seven per group), with body weight of 385-485 g, were categorized into three groups and subjected to different recovery times, each with three repetitive loading cycles at skin tissues above of right trochanter area. The first, second, and third groups were subjected to short (3 minutes), moderate (10 minutes), and prolonged (40 minutes) recovery, respectively, while applying fixed loading time and pressure (10 minutes and 50 mmHg, respectively), to provide different degree of recovery and tissue conditions (tissue damage and tissue recovery). Peak RH was measured in the three cycles to determine RH trend (increasing, decreasing, and inconsistent). All rat tissues were evaluated using ultrasound at pre- and post-experiment and rated by two raters to categorize the severity of tissue changes (no, mild, moderate, and severe). The tissue condition was also evaluated using histopathological examination to distinguish between normal and abnormal tissues. Most of the samples with increasing RH trend is related to abnormal tissue (71%); while inconsistent RH trends is more related to normal tissue (82%). There is no relationship between the tissue conditions evaluated under ultrasonographic and histopathological examination. Peak RH trend over repetitive loading may serve as a new feature for determining the tissue condition that leading to pressure ulcer.

Matched MeSH terms: Hyperemia/physiopathology*
Trends of reactive hyperaemia responses to repetitive loading on skin tissue of rats - Implications for pressure ulcer prevention

Yapp JH, Kamil R, Rozi M, Mohtarrudin N, Loqman MY, Ezamin AR, et al.

J Tissue Viability, 2017 Aug;26(3):196-201.
PMID: 28438463 DOI: 10.1016/j.jtv.2017.03.002

Tissue recovery is important in preventing tissue deterioration, which is induced by pressure and may lead to pressure ulcers (PU). Reactive hyperaemia (RH) is an indicator used to identify people at risk of PU. In this study, the effect of different recovery times on RH trend is investigated during repetitive loading. Twenty-one male Sprague-Dawley rats (seven per group), with body weight of 385-485 g, were categorised into three groups and subjected to different recovery times with three repetitive loading cycles. The first, second, and third groups were subjected to short (3 min), moderate (10 min), and prolonged (40 min) recovery, respectively, while fixed loading time and pressure (10 min and 50 mmHg, respectively). Peak hyperaemia was measured in the three cycles to determine trends associated with different recovery times. Three RH trends (increasing, decreasing, and inconsistent) were observed. As the recovery time is increased (3 min vs. 10 min vs. 40 min), the number of samples with increasing RH trend decreases (57% vs. 29% vs. 14%) and the number of samples with inconsistent RH trend increases (29% vs. 57% vs. 72%). All groups consists of one sample with decreasing RH trend (14%). Results confirm that different recovery times affect the RH trend during repetitive loading. The RH trend may be used to determine the sufficient recovery time of an individual to avoid PU development.

Matched MeSH terms: Hyperemia/physiopathology*
Assessment of macrovascular endothelial function using pulse wave analysis and its association with microvascular reactivity in healthy subjects

Ibrahim NNIN, Rasool AHG

Skin Res Technol, 2017 Aug;23(3):321-325.
PMID: 27868242 DOI: 10.1111/srt.12338

BACKGROUND: Pulse wave analysis (PWA) and laser Doppler fluximetry (LDF) are non-invasive methods of assessing macrovascular endothelial function and microvascular reactivity respectively. The aim of this study was to assess the correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF.
METHOD: 297 healthy and non-smoking subjects (159 females, mean age (±SD) 23.56 ± 4.54 years) underwent microvascular reactivity assessment using LDF followed by macrovascular endothelial function assessments using PWA.
RESULTS: Pearson's correlation showed no correlation between macrovascular endothelial function and microvascular reactivity (r = -0.10, P = 0.12).
CONCLUSION: There was no significant correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF in healthy subjects.

Matched MeSH terms: Hyperemia/physiopathology