With increasing demand for a variety of clinical diagnostics related to blood coagulability such as activated clotting time (ACT), several measurement devices have been developed. Recently, a new ACT measurement device, the Coagulometer CA-200, has become available. One issue is that there will inevitably be differences in measured ACT values among different devices. In addition, as ACT measurement becomes more widely used in clinical practice, measurement of blood coagulation will be required in patients with a wider range of blood coagulability. Consequently, the purpose of this study was to investigate blood coagulability as the function of protamine dose in heparin sodium-treated fresh human blood and to examine the correlation between measured ACT values from two devices, namely, the Coagulometer CA-200 and Hemochron Jr. Signature+.

The results showed similar ACT curves as the dose of protamine was increased, becoming asymptotic at higher coagulability conditions. Under the theoretical maximal procoagulant condition, ACT values were 108 ± 22.5 and 122 ± 11 s for the CA-200 and Hemochron devices, respectively. In blood with the maximum heparin sodium content of 7 U/mL, the measured ACT was 800 and 600 s for the respective devices. Furthermore, there was a linear relationship between the ACT measurements of the two devices. This study clearly showed the feasibility of measurement with the CA-200 and its relatively higher resolution in low coagulability conditions.

Some symptomatic patients with coronavirus disease 2019 (COVID-19) develop acute respiratory failure with mechanical ventilation support. Therefore, identifying patients who tend to experience respiratory deterioration is of great importance. We investigated blood markers upon hospital admission that could predict respiratory illness in patients with COVID-19. This retrospective observational study included 148 patients with COVID-19 admitted to our hospital. All blood marker levels of C-reactive protein (CRP), lactate dehydrogenase (LDH), D-dimer, white blood cells (WBCs), and lymphocytes were measured on admission in 148 patients. Patients were divided into the severe group (SVG), requiring mechanical ventilation therapy, and the non-severe group (nSVG). The levels of CRP, LDH, D-dimer and WBC count were significantly higher, and the lymphocyte count and lymphocyte-to-WBC count ratio (LWR) were significantly lower in the SVG than in the nSVG. The area under the receiver operating characteristic curve for CRP, LDH, D-dimer and LWR showed high values of 0.69, 0.70, 0.70, and 0.74, respectively. The age-adjusted odds ratios of D-dimer and LWR were high (5.5 [1.9–15.9] and 5.6 [2.2–14.3], respectively). D-dimer level and LWR upon admission were highly predictive of mechanical ventilation support in patients with COVID-19.

Quantification of deformation behavior of articular cartilage (AC) is crucial for understanding its mechanical function and response to mechanical stimuli. Here, we explored whether grating-based phase-contrast X-ray CT using monochromatic synchrotron light (grating-based msPXCT) enables in-situ quantification of local deformation in AC. Grating-based msPXCT of a porcine AC sample during axial compression test was conducted using a Talbot grating interferometer. Local displacements and strains were computed using a digital volume correlation method. The magnitude of axial strain decreased from the upper to middle sample zones and reached almost constant over the middle-lower zone, consistent with the depth-dependent density increase with compression. Thus, grating-based msPXCT may be suitable for quantitative analysis of AC deformation.

Pulsating flow within an elastic cerebral aneurysm model was visualized by particle image velocimetry (PIV) to clarify the effect of wall deformation on wall shear stress (WSS). In the experiment, we used a full-scale patient-specific cerebral aneurysm phantom model with a thin transparent silicone wall fabricated by soaking a plaster mold. The experiment was performed in two planes, one in the middle plane and the other perpendicular to it. The results showed that in the middle plane, the wall deformation reduced the maximum WSS in systole by about 20% and the averaged WSS by about 20% in comparison with the less-deformation model. On the other hand, for planes perpendicular to the aforementioned planes, the averaged WSS increased by about 10% in comparison with the less-deformation model. In addition, it was observed that the local WSS changed in intensity according to the plane and phase, because of movement of the separation point of the wall jet. This finding suggests that the wall deformation of cerebral aneurysm affects the magnitude of WSS.

A1 domain of von Willebrand factor (VWF) binding with platelet glycoprotein (GP) Ibα play crucial roles in platelet adhesion and subsequent passive shape changes in the platelets such as pseudopod formation under high wall shear rate conditions. However, the effects of specific inhibitors of VWF binding with GPIbα on the length of pseudopods supporting platelet adhesion on VWF are still to be elucidated. Here we measured the length of pseudopods in the presence of VWF-GPIbα inhibitor of caplacizumab. The length of pseudopods was 6.5 ± 0.2 μm (mean ± 95% confidential interval [CI]) and 6.9 ± 0.2 μm (mean ± 95% CI) at 100 and 200 nM of caplacizumab concentrations and was longer than those formed in its absence (5.2 ± 0.2 μm, p < 0.05). Our experiments also revealed that the surface area coverage by platelets in the presence of caplacizumab at a concentration of 200 nM of 26.1 ± 6.4% after 60-second blood perfusion was smaller than its absence (45.2 ± 7.5%, p < 0.05). Our results suggest that fewer numbers of VWF-GPIbα bonds generating larger binding force with a longer length of pseudopods, support the platelet adhesion on VWF in the presence of caplacizumab at a wall shear rate of 1,500 s^–1.