Evaluation of Malignant Breast Lesions Using High-resolution Readout-segmented Diffusion-weighted Echo-planar Imaging: Comparison with Pathology

Purpose:We aimed to investigate the performance of high resolution-diffusion-weighted imaging (HR-DWI) using readout-segmented echo-planar imaging in visualizing malignant breast lesions and evaluating their extent, using pathology as a reference.Methods:This retrospective study included patients who underwent HR-DWI with surgically confirmed malignant breast lesions. Two radiologists blinded to the final diagnosis evaluated HR-DWI independently and identified the lesions, measuring their maximum diameters. Another radiologist confirmed if those lesions were identical to the pathology. The maximum diameters of the lesions between HR-DWI and pathology were compared, and their correlations were calculated using Spearman’s correlation coefficient. Apparent diffusion coefficient (ADC) values of the lesions were measured.Results:Ninety-five mass/64 non-mass lesions were pathologically confirmed in 104 females. Both radiologists detected the same 93 mass lesions (97.9%). Spearman’s correlation coefficient for mass lesions were 0.89 and 0.90 (P < 0.0001 and 0001) for the two radiologists, respectively. The size differences within 10 mm were 90.3% (84/93) and 94.6% (88/93) respectively. One radiologist detected 35 non-mass lesions (54.7%) and another radiologist detected 32 non-mass lesions (50.0%), of which 28 lesions were confirmed as identical. Spearman’s correlation coefficient for non-mass lesions were 0.59 and 0.22 (P = 0.0002 and 0.22), respectively. The mean ADC value of mass lesions and non-mass lesions were 0.80 and 0.89 × 10⁻³ mm²/s, respectively.Conclusion:Using HR-DWI, malignant mass lesions were depicted with excellent agreement with the pathological evaluation. Approximately half of the non-mass lesions could not be identified, suggesting a current limitation of HR-DWI.     

Concentration Fluctuations and Segmental Dynamics in Weakly Dynamic Asymmetric Blends in the Presence of Surface‐Functionalized Multiwall Carbon Nanotubes

Surface‐functionalized multiwall carbon nanotubes (MWCNTs) are incorporated in poly(methyl methacrylate)/styrene acrylonitrile (PMMA/SAN) blends and the pretransitional regime is monitored in situ by melt rheology and dielectric spectroscopy. As the blends exhibit weak dynamic asymmetry, the obvious transitions in the melt rheology due to thermal concentration fluctuations are weak. This is further supported by the weak temperature dependence of the correlation length (ξ ≈ 10–12 Å) in the vicinity of demixing. Hence, various rheological techniques in both the temperature and frequency domains are adopted to evaluate the demixing temperature. The spinodal decomposition temperature is manifested in an increase in the miscibility gap in the presence of MWCNTs. Furthermore, MWCNTs lead to a significant slowdown of the segmental dynamics in the blends. Thermally induced phase separation in the PMMA/SAN blends lead to selective localization of MWCNTs in the PMMA phase. This further manifests itself in a significant increase in the melt conductivity.

     

Effect of exposure parameters and gutta-percha cone size on fracture-like artifacts in endodontically treated teeth on cone-beam computed tomography images

Oral Radiology - To ascertain the effects of exposure parameters (tube current and tube voltage) and the gutta-percha cone (GPC) size on root fracture-like artifacts obtained with cone-beam...     

Does time of CCI measurement affect the evaluation of platelet transfusion effectiveness?

The measurement of corrected count increment at 1-h post-transfusion (CCI-1 h) of platelet concentrate (PC) transfusion is recommended, but in the revised Japanese Guideline (2017) it was changed to “after 10-min to 1-h”, following the revision of the guidelines from Western countries. Here, we aimed to investigate on the feasibility to apply the CCI measured at 10-min or 30-min post-transfusion as the surrogate of CCI-1 h. Peripheral blood was collected at 10-min, 30-min and 1-h post-transfusion of PC and the effectiveness of the transfusion was analyzed based on the CCI. In the period from December 2017 to February 2020, 8 patients, who received multiple PC transfusion (total 208) at our institution, were analyzed. We performed the univariate analyses to examine the relationship between CCI value and the categorical variables, p-value <0.1 was obtained for gender (p = 2.91 × 10^?19), fever after transfusion (p = 0.0163). The qualitative variables, namely measurement time (p = 0.0553), also showed p-value <0.1. Using these factors as covariates in the mixed effect model, we found that the measurement time (p = 0.0007) had a significant effect on the CCI value when looking at fixed effects. Although there is a tendency for decreased CCI values with time progression, the slope of the change in the mixed model was -0.00307, indicating that the CCI difference among the 3 measurements was small. Here we provide evidence that CCI measured at 10-min and 30-min post-transfusion give results comparable to those measured at 1-h post-transfusion, under the Japanese practice of platelet transfusion, which relies on 100 % single-donor apheresis PC, and ABO-identical whenever possible.     

Regulation of sperm capacitation and the acrosome reaction by PIP2 and actin modulation

Actin polymerization and development of hyperactivated (HA) motility are two processes that take place during sperm capacitation. Actin polymerization occurs during capacitation and prior to the acrosome reaction, fast F-actin breakdown takes place. The increase in F-actin during capacitation depends upon inactivation of the actin severing protein, gelsolin, by its binding to phosphatydilinositol-4, 5-bisphosphate (PIP₂) and its phosphorylation on tyrosine-438 by Src. Activation of gelsolin following its release from PIP₂ is known to cause F-actin breakdown and inhibition of sperm motility, which can be restored by adding PIP₂ to the cells. Reduction of PIP₂ synthesis inhibits actin polymerization and motility, while increasing PIP₂ synthesis enhances these activities. Furthermore, sperm demonstrating low motility contained low levels of PIP₂ and F-actin. During capacitation there was an increase in PIP₂ and F-actin levels in the sperm head and a decrease in the tail. In spermatozoa with high motility, gelsolin was mainly localized to the sperm head before capacitation, whereas in low motility sperm, most of the gelsolin was localized to the tail before capacitation and translocated to the head during capacitation. We also showed that phosphorylation of gelsolin on tyrosine-438 depends upon its binding to PIP₂. Stimulation of phospholipase C, by Ca²⁺-ionophore or by activating the epidermal-growth-factor-receptor, inhibits tyrosine phosphorylation of gelsolin and enhances enzyme activity. In conclusion, these data indicate that the increase of PIP₂ and/or F-actin in the head during capacitation enhances gelsolin translocation to the head. As a result, the decrease of gelsolin in the tail allows the maintenance of high levels of F-actin in this structure, which is essential for the development of HA motility.To acquire the ability to fertilize the egg, mammalian spermatozoa must undergo several biochemical and morphological changes in the female reproductive tract, collectively called capacitation. These changes include cAMP/PKA activation, cholesterol efflux from the plasma membrane, PKA-dependent protein tyrosine phosphorylation, actin polymerization and the development of HA motility.1,2 In a recent study we suggested a mechanism by which the Ser/Thr targeting PKA can lead to Tyr phosphorylation of proteins in the capacitation process. We showed that PKA activates Src which, in turn, inhibits the phosphatase PP1, leading to CaMKII activation, which activates Pyk2 to phosphorylate phosphatidyl-inositol-3-kinase on tyr-458.3We have shown elsewhere that actin polymerization must take place in order to capacitate spermatozoa while very fast depolymerization of F-actin occurs prior to the acrosome reaction.4 It has been suggested that an increase in F-actin during capacitation creates a network in the sperm head between the plasma membrane and the outer acrosomal membrane, and the dispersion of this F-actin must occur to enable acrosomal exocytosis.4,5,6,7 The increase in F-actin in the sperm tail during capacitation is important for the development of HA motility.8 The latter is characterized by an increase in flagellar bending amplitude and an increase in average lateral head movement.9,10 It was shown that the efficiency of HA sperm to penetrate the egg is much higher than non-HA sperm.11 Sperm motility and HA motility are mediated by PLD-dependent actin polymerization.8 It is known that phosphatidylinositol 4,5-bisphosphate (PIP₂) is a cofactor for PLD activation in many cell types.12,13,14,15,16 PIP₂ comprises only 1% of plasma membrane phospholipids, however its extraordinary versatility puts it in the center of plasma membrane dynamics governing cell motility, adhesion, endo- and exocytosis.17,18PIP₂ serves as an effector of several proteins such as Myristoylated alanine-rich C-kinase substrate (MARCKS), gelsolin, PLD and PI3K. These proteins are present in spermatozoa19,20 and are involved in the regulation of sperm capacitation and/or the acrosome reaction. PIP₂ binds gelsolin and release it from actin filaments ends, exposing sites for actin assembly.21 We have shown that the release of bound gelsolin from PIP₂, causes rapid Ca²⁺-dependent F-actin depolymerization as well as an increased acrosome reaction.22 We have also shown that PIP₂ and gelsolin are involved in regulating sperm motility and the development of HA motility.23