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Noninvasive assessment of cutaneous vascular function in vivo using capillaroscopy, plethysmography and laser-Doppler instruments: its strengths and weaknesses

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

Clin. Hemorheol. Microcirc., 2006;34(4):457-73.
PMID: 16687786

Given that functional abnormalities of the microcirculation are one of the primary abnormalities in cardiovascular disease pathogenesis, various noninvasive clinical tools have been developed recently to assess the microvascular function, particularly at the skin. The common techniques used to assess cutaneous microvascular function in vivo include capillaroscopy, venous occlusion plethysmography, and laser-Doppler instruments (laser-Doppler fluximetry and laser-Doppler imaging). These noninvasive techniques can be used as an early measure of functional abnormalities within the microvascular tree, predominantly in population at high risk for cardiovascular events. This review discusses some underlying application principle of these techniques, including its clinical significance, method reproducibility and limitations.

Matched MeSH terms: Plethysmography*
A comparison of brain phantom relative permittivity with CST simulation library and existing research

Chew KM, Seman N, Sudirman R, Yong CY

Biomed Mater Eng, 2014;24(6):2161-7.
PMID: 25226914 DOI: 10.3233/BME-141027

The development of human-like brain phantom is important for data acquisition in microwave imaging. The characteristics of the phantom should be based on the real human body dielectric properties such as relative permittivity. The development of phantom includes the greymatter and whitematter regions, each with a relative permittivity of 38 and 28 respectively at 10 GHz frequency. Results were compared with the value obtained from the standard library of Computer Simulation Technology (CST) simulation application and the existing research by Fernandez and Gabriel. Our experimental results show a positive outcome, in which the proposed mixture was adequate to represent real human brain for data acquisition.

Matched MeSH terms: Plethysmography, Impedance/instrumentation*; Plethysmography, Impedance/methods
Fulltext The theory and fundamentals of bioimpedance analysis in clinical status monitoring and diagnosis of diseases

Khalil SF, Mohktar MS, Ibrahim F

Sensors (Basel), 2014;14(6):10895-928.
PMID: 24949644 DOI: 10.3390/s140610895

Bioimpedance analysis is a noninvasive, low cost and a commonly used approach for body composition measurements and assessment of clinical condition. There are a variety of methods applied for interpretation of measured bioimpedance data and a wide range of utilizations of bioimpedance in body composition estimation and evaluation of clinical status. This paper reviews the main concepts of bioimpedance measurement techniques including the frequency based, the allocation based, bioimpedance vector analysis and the real time bioimpedance analysis systems. Commonly used prediction equations for body composition assessment and influence of anthropometric measurements, gender, ethnic groups, postures, measurements protocols and electrode artifacts in estimated values are also discussed. In addition, this paper also contributes to the deliberations of bioimpedance analysis assessment of abnormal loss in lean body mass and unbalanced shift in body fluids and to the summary of diagnostic usage in different kinds of conditions such as cardiac, pulmonary, renal, and neural and infection diseases.

Matched MeSH terms: Plethysmography, Impedance/instrumentation; Plethysmography, Impedance/methods*
Body plethysmography for measuring airway resistance in patients with bilateral vocal fold immobility

Sairin ME, Mat Baki M, Manap RA, Puteh SEW, Azman M, Mohamed AS

Auris Nasus Larynx, 2020 Oct;47(5):842-848.
PMID: 32273190 DOI: 10.1016/j.anl.2020.03.004

OBJECTIVE: This study investigated the reliability of body plethysmography in comparison to spirometry in objectively measuring upper airway functions.
METHODS: The study population consisted of 53 participants, 23 patients with BVFI after endolaryngeal laser posterior cordectomy and 30 healthy volunteers. All of them had body plethysmography (airway resistance, Raw), spirometry (ratio of forced expiratory flow at 50% to forced inspiratory flow at 50%, FEF50/FIF50 and peak inspiratory flow, PIF), 6 min-walking-test (6MWT) and Medical Research Council (MRC) dyspnea scale measurements. The tests were repeated and reliability was evaluated using intraclass correlation (ICC) and Spearman correlation.
RESULTS: The reliability of Raw was high with ICC of 0.92, comparable to the spirometry measurements: FEF50/FIF50(ICC = 0.72) and PIF (ICC = 0.97). The mean of Raw was significantly higher in patient group. A strong significant correlation between Raw and MRC dyspnea scale (r = 0.79; p<0.05) and a moderate negative correlation between Raw and 6MWT (r = 0.4; p<0.05) was demonstrated.
CONCLUSION: Body plethysmography (Raw) is a reliable tool in objective measurement of upper airway resistance that reflects the patient's perception of breathlessness. A larger number of participants are necessary to confirm this finding.

Matched MeSH terms: Plethysmography, Whole Body
Fulltext Modeling of hemoglobin in dengue fever and dengue hemorrhagic fever using bioelectrical impedance

Ibrahim F, Ismail NA, Taib MN, Wan Abas WA

Physiol Meas, 2004 Jun;25(3):607-15.
PMID: 15253113 DOI: 10.1088/0967-3334/25/3/002

This paper describes a model for predicting hemoglobin (Hb) by using bioelectrical impedance analysis (BIA) in dengue patients in the Hospital Universiti Kebangsaan Malaysia (HUKM). Bioelectrical impedance measurements were conducted on 83 (47 males and 36 females) serologically confirmed dengue fever (DF) and dengue hemorrhagic fever (DHF) patients during their hospitalization. The predictive equation for Hb was derived using multivariate analysis. We investigated all the parameters in BIA, patients' symptom and demographic data. In this developed model, four predictors (reactance (XC), sex, weight and vomiting) were found to be the best predictive factors for modeling Hb in dengue patients. However, the model can only explain approximately 42% of the variation in Hb status, thus single frequency bio-impedance stand-alone technique is insufficient to monitor Hb for the DF and DHF patients. Further investigation using multi-frequency BIA is recommended in modeling Hb to achieve the most parsimonious model.

Matched MeSH terms: Plethysmography, Impedance/methods*
A geranyl acetophenone targeting cysteinyl leukotriene synthesis prevents allergic airway inflammation in ovalbumin-sensitized mice

Ismail N, Jambari NN, Zareen S, Akhtar MN, Shaari K, Zamri-Saad M, et al.

Toxicol Appl Pharmacol, 2012 Mar 1;259(2):257-62.
PMID: 22266348 DOI: 10.1016/j.taap.2012.01.003

Asthma is associated with increased pulmonary inflammation and airway hyperresponsiveness. The current use of corticosteroids in the management of asthma has recently raised issues regarding safety and lack of responsiveness in 5-10% of asthmatic individuals. The aim of the present study was to investigate the therapeutic effect of a non-steroidal small molecule that has cysteinyl leukotriene (cysLT) inhibitory activity, upon attenuation of allergic lung inflammation in an acute murine model. Mice were sensitized with ovalbumin (OVA) and treated with several intraperitoneal doses (100, 20, 2 and 0.2mg/kg) of 2,4,6,-trihydroxy-3-geranylacetophenone (tHGA). Bronchoalveolar lavage was performed, blood and lung samples were obtained and respiratory function was measured. OVA sensitization increased pulmonary inflammation and pulmonary allergic inflammation was significantly reduced at doses of 100, 20 and 2mg/kg with no effect at the lowest dose of 0.2mg/kg. The beneficial effects in the lung were associated with reduced eosinophilic infiltration and reduced secretion of Th2 cytokines and cysLTs. Peripheral blood reduction of total IgE was also a prominent feature. Treatment with tHGA significantly attenuated altered airway hyperresponsiveness as measured by the enhanced pause (Penh) response to incremental doses of methacholine. These data demonstrate that tHGA, a synthetic non-steroidal small molecule, can prevent acute allergic inflammation. This proof of concept opens further avenues of research and development of tHGA as an additional option to the current armamentarium of anti-asthma therapeutics.

Matched MeSH terms: Plethysmography, Whole Body