Biorheology - Volume 54, issue 1

Authors: Sokolis, Dimitrios P. | Dimitriou, Constantinos A. | Lelovas, Pavlos | Kostomitsopoulos, Nikolaos G. | Dontas, Ismene A.

Article Type: Research Article

Abstract: BACKGROUND: Arterial function is regulated by estrogen, but no consistent pattern of arterial mechanical remodeling in response to depleted estrogen levels is available. OBJECTIVE: To examine long-term effects of ovariectomy (OVX) on the mechanical properties, morphology, and histological structure of the carotid artery in middle-aged rats and a potentially protective effect of Sideritis euboea extract (SID), commonly consumed as “mountain tea”. METHODS: 10-month-old female Wistar rats were allocated into control (sham-operated), OVX, OVX + SID , and OVX + MALT (maltodextrin; excipient used for dilution of SID) groups. They were …sacrificed after 6 months and their carotid arteries were submitted to inflation/extension tests and to dimensional and histological evaluation. RESULTS: Remodeling in OVX rats was characterized by a decreased in situ axial extension ratio, along with increased opening angle, thickness, and area of the vessel wall and of its medial layer, but unchanged lumen diameter. Compositional changes involved increased elastin/collagen densities. Characterization by the “four-fiber” microstructure-motivated model revealed similar in situ biaxial response of carotid arteries in OVX and control rats. CONCLUSIONS: Carotid artery remodeling in OVX rats was largely consistent with hypertensive remodeling, despite the minor arterial pressure changes found, and was not altered by administration of SID, despite previous evidence of its osteo-protective effect. Show more

Keywords: Carotid artery, mechanical testing, material characterization, opening angle, collagen

DOI: 10.3233/BIR-16113

Citation: Biorheology, vol. 54, no. 1, pp. 1-23, 2017

Authors: Hayashi, Yoshihito | Brun, Marc-Aurèle | Machida, Kenzo | Lee, Seungmin | Murata, Aya | Omori, Shinji | Uchiyama, Hidetoshi | Inoue, Yoshinori | Kudo, Toshifumi | Toyofuku, Takahiro | Nagasawa, Masayuki | Uchimura, Isao | Nakamura, Tomomasa | Muneta, Takeshi

Article Type: Research Article

Abstract: Background: In a whole blood coagulation test, the concentration of any in vitro diagnostic agent in plasma is dependent on the hematocrit level but its impact on the test result is unknown. Objective: The aim of this work was to clarify the effects of reagent concentration, particularly Ca2+ , and to find a method for hematocrit estimation compatible with the coagulation test. Methods: Whole blood coagulation tests by dielectric blood coagulometry (DBCM) and rotational thromboelastometry were performed with various concentrations of Ca2+ or on samples with different hematocrit levels. DBCM data from a previous clinical …study of patients who underwent total knee arthroplasty were re-analyzed. Results: Clear Ca2+ concentration and hematocrit level dependences of the characteristic times of blood coagulation were observed. Rouleau formation made hematocrit estimation difficult in DBCM, but use of permittivity at around 3 MHz made it possible. The re-analyzed clinical data showed a good correlation between permittivity at 3 MHz and hematocrit level (R 2 = 0.83 ). Conclusions: Changes in the hematocrit level may affect whole blood coagulation tests. DBCM has the potential to overcome this effect with some automated correction using results from simultaneous evaluations of the hematocrit level and blood coagulability. Show more

Keywords: Dielectric spectroscopy, rotational thromboelastometry, whole blood coagulation test, rouleau formation, interfacial polarization

DOI: 10.3233/BIR-16118

Citation: Biorheology, vol. 54, no. 1, pp. 25-35, 2017

Authors: Koliamitra, Christina | Holtkamp, Bastian | Zimmer, Philipp | Bloch, Wilhelm | Grau, Marijke

Article Type: Research Article

Abstract: Background: Acute exercise increases red blood cell-nitric oxide synthase (RBC-NOS) activation and RBC deformability but the effect of regular training remains unclear. Objective: To detect the chronic effect of enduring moderate and high intensity training on the RBC-NOS/NO pathway and to detect a relation between RBC deformability and endurance capacity. Methods: 38 healthy male subjects were randomly assigned to one of three training groups: High Volume Training (HVT; 120–140 beats per minute (bpm)), High Intensity Training (HIT; 160–180 bpm) and Moderate Intensity Training (MIT; 140–160 bpm). Blood parameters, maximum oxygen capacity (VO2 max), RBC deformability, …RBC nitrite level and RBC-NOS activation were measured after venous blood sampling at rest pre (T0) and after six weeks of training (T1). Results: RBC-NOS activation, RBC nitrite concentration and RBC deformability were significantly increased at T1 in the HIT group. Parameters were unaltered in MIT and HVT. Maximum oxygen uptake was only significantly increased in the HIT group and regression analysis revealed positive regression between VO2 max and RBC deformability. Conclusions: High intensity training was the only training programme that sustainably affected RBC-NOS dependent NO production and performance capacity. HIT therefore represents a time efficient training program resulting in improved RBC function potentially improving physical condition. Show more

Keywords: Nitric oxide, red blood cell deformability, red blood cell-nitric oxide synthase, exercise

DOI: 10.3233/BIR-16121

Citation: Biorheology, vol. 54, no. 1, pp. 37-50, 2017