Clinical Hemorheology and Microcirculation - Volume 57, issue 2

Authors: Jung, F. | Gori, Tommaso

Article Type: Other

DOI: 10.3233/CH-141819

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 93-94, 2014

Authors: Pavlovic, Dragan | Usichenko, Taras I. | Lehmann, Christian

Article Type: Research Article

Abstract: Some open access journals are believed to have devaluated the highly respected image of the scientific journal. This has been, it is claimed, verified. Yet the project we believe failed and we show why we think that it failed. The study itself was badly conducted and the report, which Science published, was itself a perfect example of “bad science”. If the article that was published in Science were to be taken as one of the “test” articles and Science as a victim journal (a perfect control though), the study would show the opposite of what author concluded in his paper: …100% of the controls (normal non-open access journals, in the present study this was Science) accepted the “bait” paper for publication, while in the experimental group only about 60% (open access journals) accepted the bait paper for publication. The conclusion is that, with respect to non-open access and open access, the probability of accepting pseudoscience is well in favor of this being done by a non-open access journal. Since this interpretation is based on some facts that were not included in the project itself, the only warranted result of this study would be that nothing could be concluded from it. It is concluded that the method that Bohannon used was heavily flawed and in addition immoral; that the report that was published by Science was inconclusive and that the act of publishing such report cannot be morally justified either. Various methods to improve the quality of published papers exist but scientific fraud with “good intentions” as a method to promote scientific publishing should be avoided. Show more

Keywords: Open access, peer review, scientific publishing, morality of publishing, Bohannon

DOI: 10.3233/CH-141820

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 95-99, 2014

Authors: Paprottka, P.M. | Zengel, P. | Cyran, C.C. | Ingrisch, M. | Nikolaou, K. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To evaluate the ultrasound tissue elasticity imaging by comparison to multimodality imaging using image fusion with Magnetic Resonance Imaging (MRI) and conventional grey scale imaging with additional elasticity-ultrasound in an experimental small-animal-squamous-cell carcinoma-model for the assessment of tissue morphology. METHOD AND MATERIALS: Human hypopharynx carcinoma cells were subcutaneously injected into the left flank of 12 female athymic nude rats. After 10 days (SD ± 2) of subcutaneous tumor growth, sonographic grey scale including elasticity imaging and MRI measurements were performed using a high-end ultrasound system and a 3T MR. For image fusion the contrast-enhanced MRI DICOM data set was …uploaded in the ultrasonic device which has a magnetic field generator, a linear array transducer (6–15 MHz) and a dedicated software package (GE Logic E9), that can detect transducers by means of a positioning system. Conventional grey scale and elasticity imaging were integrated in the image fusion examination. After successful registration and image fusion the registered MR-images were simultaneously shown with the respective ultrasound sectional plane. Data evaluation was performed using the digitally stored video sequence data sets by two experienced radiologist using a modified Tsukuba Elasticity score. The colors “red and green” are assigned for an area of soft tissue, “blue” indicates hard tissue. RESULTS: In all cases a successful image fusion and plan registration with MRI and ultrasound imaging including grey scale and elasticity imaging was possible. The mean tumor volume based on caliper measurements in 3 dimensions was ~323 mm3 . 4/12 rats were evaluated with Score I, 5/12 rates were evaluated with Score II, 3/12 rates were evaluated with Score III. There was a close correlation in the fused MRI with existing small necrosis in the tumor. None of the scored II or III lesions was visible by conventional grey scale. CONCLUSION: The comparison of ultrasound tissue elasticity imaging enables a secure differentiation between different tumor tissue areas in comparison to image fusion with MRI in our small study group. Therefore ultrasound tissue elasticity imaging might be used for fast detection of tumor response in the future whereas conventional grey scale imaging alone could not provide the additional information. By using standard, contrast-enhanced MRI images for reliable and reproducible slice positioning, the strongly user-dependent limitation of ultrasound tissue elasticity imaging may be overcome, especially for a comparison between baseline and follow-up measurements. Show more

Keywords: Image fusion, multimodality imaging, magnetic resonance imaging (MRI), ultrasound tissue elasticity imaging, experimental animal model

DOI: 10.3233/CH-141821

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 101-110, 2014

Authors: Moh, Jeong-Hah | Cho, Young I. | Cho, Daniel J. | Kim, Doosang | Banerjee, Rupak K.

Article Type: Research Article

Abstract: The present research investigated the role of blood viscosity on flow within a microvascular network to identify the conditions of blood flow stagnation. When the yield stress of blood was less than 0.005 Pa, there were no stagnant regions in the microvasculature. However, when the yield stress increased to 0.05 Pa, stagnant or reduced flow areas began to appear, which grew and expanded rapidly with further increase in the yield stress. Thus, the yield stress determined from blood viscosity profile of a patient can be utilized to evaluate the risk of circulatory impairment.

Keywords: Yield stress, wall shear stress, hemostasis, Herschel-Bulkley model, microvascular flow, microvessels, capillary network

DOI: 10.3233/CH-141822

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 111-118, 2014

Authors: Teległów, Aneta | Dąbrowski, Zbigniew | Marchewka, Anna | Tyka, Aleksander | Krawczyk, Marcin | Głodzik, Jacek | Szyguła, Zbigniew | Mleczko, Edward | Bilski, Jan | Tyka, Anna | Tabarowski, Zbigniew | Czepiel, Jacek | Filar-Mierzwa, Katarzyna

Article Type: Research Article

Abstract: The aim of this study was to analyze the changes in blood rheology resulting from regular winter swimming. The study was carried out on 12 male winter swimmers. Venous blood for morphological, biochemical and rheological analysis was sampled twice from each winter swimmer – at the beginning of the season and after its completion. There were no significant changes detected in the median values of most blood morphological parameters. The only exception pertained to MCHC which was significantly lower after the season. Winter swimming entailed significant decrease in median elongation index values at shear stress levels of 0.30 Pa and …0.58 Pa, and significant increase in median values of this parameter at shear stress levels ≥1.13 Pa. No significant changes were observed in winter swimmers' median values of aggregation indices and plasma viscosity. The median level of glucose was lower post winter swimming in comparison to the pre-seasonal values. In contrast, one season of winter swimming did not influence swimmers' median value of fibrinogen concentration. In summary, this study revealed positive effects of winter swimming on the rheological properties of blood, manifested by an increase in erythrocyte deformability without accompanying changes in erythrocyte aggregation. Show more

Keywords: Aggregation index, deformability, elongation index, erythrocyte, plasma viscosity

DOI: 10.3233/CH-141823

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 119-127, 2014

Authors: Rjosk-Dendorfer, D. | Gürtler, V.M. | Sommer, W.H. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To evaluate the additional effect of higher frequent linear probes than 12.5 MHz in color Doppler sonography and free hand sonoelastography of benign and malignant breast masses and to compare different color encodings in sonoelastography. MATERIALS AND METHODS: From December 2012 to March 2013, 37 patients with benign or malignant breast masses were prospectively included in this study. All solid masses have been histologically proven. Two readers assessed sonoelastographic findings at 12.5 MHz vs. 17 MHz according to the tsukuba elasticity score and additionally different color encodings were compared. Results of Doppler sonography using a score of 0, 1 …or 2, depending on the degree of perfusion, also were assessed at 12.5 MHz vs. 17 MHz. RESULTS: Among the 37 examined breast masses there were 10 cysts, 16 fibroadenomas and 11 carcinomas. Median participant age was 49.0 years. Use of color Doppler sonography enabled to distinguish cysts from solid breast masses (p < 0.001), without an improvement at 17 MHz. Additional sonoelastography significantly improved the specificity in solid breast masses (p < 0.001). No changes could be seen using different colors in sonoelastography. CONCLUSION: Combination of color Doppler sonography and sonoelastography can increase the accuracy in distinguishing benign from malignant breast masses. The use of linear probes with a higher frequency than 12.5 MHz does not show any benefit, neither in color Doppler sonography nor in sonoelastography. Show more

Keywords: Breast neoplasm, ultrasound, elastography, doppler sonography

DOI: 10.3233/CH-141824

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 129-135, 2014

Authors: Lehmann, Ch. | Abdo, I. | Kern, H. | Maddison, L. | Pavlovic, D. | Sharawi, N. | Starkopf, J. | Hall, R. | Johnson, P. | Williams, L. | Cerny, V. | on behalf of the MiDAS (Microcirculation Diagnostics and Applied Studies) group

Article Type: Research Article

Abstract: INTRODUCTION: In clinical setting, Sidestream Dark Field (SDF) imaging has provided unprecedented insights into the gut microcirculation mainly by studying the intestinal mucosa of patients with ileostomies. Visualizing microvascular structure and function of ileal mucosa at the bedside brings unique opportunity for clinical research, particularly in critically ill patients. Several papers that were focused on intestinal microcirculation, used different methods of assessment because an accepted scoring systems does not exist so far and it is no surprise that it is rather difficult to compare the results from these studies. The present paper presents recommendations concerning specific aspects of image acquisition …and proposes some parameters for the description of the intestinal microcirculation in human studies, as suggested by the participants of a round table meeting. METHODS: The round table meeting participants reviewed all relevant literature, discussed various aspects of image acquisition by SDF technology in patients with ileostomy and parameters for the description of intestinal mucosa microcirculation. Selected key conditions for high quality and reproducible image recordings were identified. To evaluate quality of intestinal microcirculation, selected parameters and scoring system were suggested and described. RESULTS: For image acquisition in ileostomies, five key points were proposed: optimal timing, optimal SDF device probe positioning, optimal stabilization, optimal number and length of acquired video recordings, and optimal avoidance of pressure artefacts. With regard to image analysis, simplified set of quantitative and qualitative parameters for the description of the intestinal mucosa microcirculation for the clinical studies has been proposed: vessels per villus, microvascular flow index, proportion of perfused villi, and borders of villi. The proposed parameters can be included in a semi-quantitative scoring system; however, this scoring system needs further validation. This simplified analysis does not require sophisticated software and can be performed manually on the video screen. CONCLUSION: We propose a simple methodology for image acquisition and suggest specific microvascular parameters to analyze SDF imaging studies of the intestinal mucosa microcirculation in patients with ileostomy. Proposed scoring system needs to be validated in further clinical studies. Show more

Keywords: Microcirculation, intestine, human, sidestream dark field imaging

DOI: 10.3233/CH-141810

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 137-146, 2014

Authors: Schulz, Christian | von Rüsten-Lange, Maik | Krüger, Anne | Lendlein, Andreas | Jung, Friedrich

Article Type: Research Article

Abstract: BACKGROUND: Occlusions of artificial small-diameter cardiovascular grafts are frequent events after implantation, often caused by clot formations. A main factor is the insufficient hemocompatibility of the inner artificial graft surface, which could be improved by endothelialization. Therefore, one challenge in cardiovascular graft engineering is the establishment of a shear-resistant endothelial cell layer to prevent cell detachment by shear forces after implantation. MATERIALS AND METHODS: Recently, very smooth (Rq = 2.37 ± 1.40 nm) poly(ether imide) (PEI) films were introduced as a biocompatible candidate material for cardiovascular devices. In this study the stability of primary human umbilical vein endothelial cell …(HUVEC) monolayer was investigated after long-term seeding (nine days) on PEI-films and subsequent exposure to a venous shear stress of 3 dyn/cm2 for up to six hours using the cone-and-plate shearing technique. Cell density, growth pattern and morphology of HUVEC were determined prior and after shearing compared to glass as control substrate. HUVEC adhering to the substrate after shear stress were counted and analyzed by fluorescent staining. Supernatants were collected and secretion profile analysis of vasoactive and inflammatory mediators was performed. RESULTS: The cell density on PEI-films compared to the controls was slightly higher after long-term seeding and exposure to shear stress (glass: 71,656 ± 8,830 cells/cm2 and 42,239 ± 5,607 cells/cm2 ; PEI-film: 64,056 ± 2,829 cells/cm2 and 45,422 ± 2,507 cells/cm2 before and after shear stress, respectively). Actin- and vinculin-staining revealed a scattered re-organization of the cytoskeleton as well as a formation of stress fibers and focal adhesion points. Secretion of prostacyclin and thromboxane A2 was increased after application of shear stress, but no significant differences were detectable between cells growing on PEI-films or glass. Amounts of secreted inflammatory cytokines IL-6 and IL-8 in the supernatant were significantly lower for HUVEC seeded on PEI-films compared to glass before as well as after stress. CONCLUSION: The study demonstrated that HUVEC were able to resist exposure to venous shear stress when seeded on smooth PEI-films with typical morphology and adhesion behavior. However, HUVEC adherence on PEI was not yet sufficient to retain a complete cell monolayer after shear stress exposure. Occasionally, single cells or cell plaques were disrupted resulting in cell free areas in the confluent HUVEC layer. Apart from this our data suggest that PEI is a suitable substrate for HUVEC under static and dynamic conditions and therefore a promising candidate material for cardiovascular applications. The next objective is a surface functionalization of the PEI-films in a cell specific manner to reach a functionally confluent, shear resistant HUVEC monolayer. Show more

Keywords: Endothelial cells, shear resistance, polymer substrate, shear stress

DOI: 10.3233/CH-141826

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 147-158, 2014

Authors: Antonova, N. | Dong, X. | Tosheva, P. | Kaliviotis, E. | Velcheva, I.

Article Type: Research Article

Abstract: The results for blood flow in the carotid artery bifurcation on the basis of numerical simulation of Navier-Stokes equations are presented in this study. Four cases of carotid bifurcation are considered: common carotid artery (CCA) bifurcation without stenoses and cases with one, two and three stenoses are also presented. The results are obtained by performing numerical simulations considering one pulse wave period based on the finite volume discretization of Navier-Stokes equations. The structures of the flow around the bifurcation are obtained and the deformation of the pulse wave from common carotid artery (CCA) to the internal carotid artery (ICA) and …external carotid artery (ECA) is traced. The axial velocity and wall shear stress (WSS) distribution and contours are presented considering the characteristic time points. The results of the WSS distribution around the bifurcation allow a prediction of the probable sites of stenosis growth. Show more

Keywords: 3D blood flow numerical analysis, carotid bifurcation, stenosis, wall shear stress, whole blood viscosity

DOI: 10.3233/CH-141827

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 159-173, 2014

Authors: Gürtler, V.M. | Rjosk-Dendorfer, D. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To compare compression elastography and contrast enhanced ultrasound in the follow-up after endovascular aortic aneurysm repair. MATERIAL AND METHODS: In this retrospective study a cohort of 33 patients with both CEUS and elastography follow-up examinations after EVAR were included. The examinations were done with a Siemens S 2000 with curved array 4 MHz multi-frequency transducer. RESULTS: Regarding our inclusion and exclusion criteria we obtained 33 patients. CEUS was used as the preferred examination in determining the presence of an endoleak. The true positive rate for the detection of Endoleaks with compression elastography was 42.4% (14/33), the false positive rate …was 12.1% (4/33), the true negative rate was 15.2% (5/33) and the false negative rate was 30.3% (10/33). The sensitivity of compression elastography was therefore 58.3% and the specifity was 55.6%. Kappa coefficient was 0.115. CONCLUSION: Compression elastography does not seem to have any additional advantages in the detection and classification of endoleaks in comparison to CEUS. Show more

Keywords: Endoleak, EVAR, AAA, CEUS, compression elastography

DOI: 10.3233/CH-141828

Citation: Clinical Hemorheology and Microcirculation, vol. 57, no. 2, pp. 175-183, 2014