Clinical utility of dynamic-enhanced MRI in salivary gland tumors: retrospective study and literature review

PURPOSE

To improve the diagnoses of the salivary gland tumors, a dynamic-enhanced MRI (dMRI) was investigated.

METHODS

We conducted a retrospective chart review of 93 cases of salivary gland tumors. The histological diagnoses were obtained from all patients using a surgical specimen and/or an open biopsy specimen. The dMRI as well as fine-needle aspiration cytology (FNAC) and intraoperative frozen section (IFS) were analyzed. This study focused on the time-intensity curve (TIC) after injection, peak time (Tpeak), washout ratio (WR) as well as the gradient of enhancement and washout profile.

RESULTS

The histological diagnoses included pleomorphic adenoma (PMA) in 53 cases, the Warthin tumors (WT) in 14 cases and malignant tumors (MT) in 26 cases. Incorrect diagnosis rate of FNAC and IFS were 5.2 and 8.3%, respectively. The TIC revealed differences among the three types of tumors. Tpeak as well as WR also revealed significant differences (p < 0.001). Tpeak were lower in order of WT, MT, PMA, respectively. WR of TICs at 30, 45 and 105 s after Tpeak were higher in order of WT, MT, PMA, respectively (p < 0.001). The gradient of increment and washout in the TIC curve was also an important parameter to distinguish the three types of tumors. In MT, the rapid enhancement pattern was found in high or intermediate histological grade tumors, whereas the slow enhancement pattern was exhibited in low grade tumors.

CONCLUSIONS

Our findings indicate that using Tpeak and WR, it is possible to distinguish between WT, PMA and MT. Additionally, a rapid enhancement pattern may be a potential marker for these tumors.

Experimental Right Ventricular Hypertension Induces Regional β1-Integrin-Mediated Transduction of Hypertrophic and Profibrotic Right and Left Ventricular Signaling

BACKGROUND

Development of right ventricular (RV) hypertension eventually contributes to RV and left ventricular (LV) myocardial fibrosis and dysfunction. The molecular mechanisms are not fully elucidated.

METHODS AND RESULTS

Pulmonary artery banding was used to induce RV hypertension in rats in vivo. Then, we evaluated cardiac function and regional remodeling 6 weeks after pulmonary artery banding. To further elucidate mechanisms responsible for regional cardiac remodeling, we also mimicked RV hypertensive stress by cyclic mechanical stretching applied to confluent cultures of cardiac fibroblasts, isolated from the RV free wall, septal hinge points, and LV free wall. Echocardiography and catheter evaluation demonstrated that rats in the pulmonary artery banding group developed RV hypertension with leftward septal displacement, LV compression, and increased LV end-diastolic pressures. Picrosirius red staining indicated that pulmonary artery banding induced marked RV fibrosis and dysfunction, with prominent fibrosis and elastin deposition at the septal hinge points but less LV fibrosis. These changes were associated with proportionally increased expressions of integrin-β1 and profibrotic signaling proteins, including phosphorylated Smad2/3 and transforming growth factor-β1. Moreover, mechanically stretched fibroblasts also expressed significantly increased levels of α-smooth muscle actin, integrin-β1, transforming growth factor-β1, collagen I deposition, and wrinkle formation on gel assays, consistent with myofibroblast transformation. These changes were not observed in parallel cultures of mechanically stretched fibroblasts, preincubated with the integrin inhibitor (BTT-3033).

CONCLUSIONS

Experimentally induced RV hypertension triggers regional RV, hinge-point, and LV integrin β1-dependent mechanotransduction signaling pathways that eventually trigger myocardial fibrosis via transforming growth factor-β1 signaling. Reduced LV fibrosis and preserved global function, despite geometrical and pressure aberrations, suggest a possible elastin-mediated protective mechanism at the septal hinge points.

Evidence for magnetic Weyl fermions in a correlated metal

Weyl fermions have been observed as three-dimensional, gapless topological excitations in weakly correlated, inversion-symmetry-breaking semimetals. However, their realization in spontaneously time-reversal-symmetry-breaking phases of strongly correlated materials has so far remained hypothetical. Here, we report experimental evidence for magnetic Weyl fermions in Mn₃Sn, a non-collinear antiferromagnet that exhibits a large anomalous Hall effect, even at room temperature. Detailed comparison between angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations reveals significant bandwidth renormalization and damping effects due to the strong correlation among Mn 3d electrons. Magnetotransport measurements provide strong evidence for the chiral anomaly of Weyl fermions-namely, the emergence of positive magnetoconductance only in the presence of parallel electric and magnetic fields. Since weak magnetic fields (approximately 10 mT) are adequate to control the distribution of Weyl points and the large fictitious fields (equivalent to approximately a few hundred T) produced by them in momentum space, our discovery lays the foundation for a new field of science and technology involving the magnetic Weyl excitations of strongly correlated electron systems such as Mn₃Sn.

Comprehensive echocardiographic assessment of biventricular function in the rabbit, animal model in cardiovascular research: feasibility and normal values

Quantification of cardiac structure and function is central in cardiovascular research. Rabbits are valuable research models of cardiovascular human disease; however, there is little normal data available. The aim of this study was to investigate feasibility and provide normal values for comprehensive echocardiographic assessment of biventricular function in rabbits. New Zealand white rabbits underwent trans-thoracic echocardiography using a general electric (GE) Vivid 7/E9 system with a 10 MHz transducer, under light sedation, to evaluate biventricular function and dimensions. Images for two-dimensional, M-mode, tissue Doppler imaging (TDI) and speckle-tracking strain echocardiography were acquired and analysed. 55 male rabbits (sized matched with a newborn human baby) were studied, mean weight was 2.9 ± 0.23 kg. Adequate images were obtained in 90% for the left ventricle (LV) and 80% for the right ventricle (RV). Two-dimensional speckle-tracking strain was feasible in 60%. Average heart rate was 248 ± 36 beats per minute; LV ejection faction 72 ± 8.0; RV fractional area change 45.9 ± 9.0%; RV myocardial performance index 0.39 ± 0.35; tricuspid annular planar systolic excursion 0.60 ± 0.24 cm. LV TDI parameters were S' 8.6 ± 3.1 cm/s; E' 12.0 ± 4.46 cm/s. RV TDI parameters were S' 10.49 ± 3.18; E' 14.95 ± 4.64 cm/s. LV and RV global peak systolic longitudinal strain were -17 ± 5 and -22 ± 8%, respectively. Comprehensive investigation of biventricular dimensions and function by echocardiography is feasible in the rabbit. Apical views and strain imaging have lower feasibility. Normal values of LV and RV functional parameters are with comparable values to human children. Animal cardiovascular research is key to develop new goals in clinical practice.

Influence of surface treatment of contaminated lithium disilicate and leucite glass ceramics on surface free energy and bond strength of universal adhesives

This study investigates the influence of surface treatment of contaminated lithium disilicate and leucite glass ceramic restorations on the bonding efficacy of universal adhesives. Lithium disilicate and leucite glass ceramics were contaminated with saliva, and then cleaned using distilled water (SC), or 37% phosphoric acid (TE), or hydrofluoric acid (CE). Specimens without contamination served as controls. The surface free energy was determined by measuring the contact angles formed when the three test liquids were placed on the specimens. Bond strengths of the universal adhesives were also measured. Saliva contamination and surface treatment of ceramic surfaces significantly influenced the surface free energy. The bond strengths of universal adhesives were also affected by surface treatment and the choice of adhesive materials. Our data suggest that saliva contamination of lithum disilicate and leucite glass ceramics significantly impaired the bonding of the universal adhesives, and reduced the surface free energy of the ceramics.

Flexible Electronic Substrate Film Fabricated Using Natural Clay and Wood Components with Cross-Linking Polymer

Requirements for flexible electronic substrate are successfully accomplished by green nanocomposite film fabricated with two natural components: glycol-modified biomass lignin and Li⁺ montmorillonite clay. In addition to these major components, a cross-linking polymer between the lignin is incorporated into montmorillonite. Multilayer-assembled structure is formed due to stacking nature of high aspect montmorillonite, resulting in thermal durability up to 573 K, low thermal expansion, and oxygen barrier property below measurable limit. Preannealing for montmorillonite and the cross-linking formation enhance moisture barrier property superior to that of industrial engineering plastics, polyimide. As a result, the film has advantages for electronic film substrate. Furthermore, these properties can be achieved at the drying temperature up to 503 K, while the polyimide films are difficult to fabricate by this temperature. In order to examine its applicability for substrate film, flexible electrodes are finely printed on it and touch sensor device can be constructed with rigid elements on the electrode. In consequence, this nanocomposite film is expected to contribute to production of functional materials, progresses in expansion of biomass usage with low energy consumption, and construction of environmental friendly flexible electronic devices.

Development of water vapor transmission rate measuring device using a quadrupole mass spectrometer and standard gas barrier films down to the 10-6 g m-2 day-1 level

Water vapor transmission rate (WVTR) measuring devices with a quadrupole mass spectrometer (QMS) have an advantage in measuring low WVTRs because measurements are taken under an extremely low background of water vapor by realizing ultrahigh vacuum conditions. Here, the reliability of the QMS measurements was improved by including a porous plug with known molecular conductance in the device to generate a reference molar flux for in situ QMS calibration. Then, standard gas barrier (SGB) films made from a clay-polyimide nanocomposite film were also developed and used to validate the measurement. The measurement results for the SGB films were on the extrapolated calibration curve obtained with the porous plug down to WVTR at the 10^-6 g m^-2 day^-1 level within the estimated measurement uncertainty.

Using Respiration to Predict Who Will Speak Next and When in Multiparty Meetings

Techniques that use nonverbal behaviors to predict turn-changing situations—such as, in multiparty meetings, who the next speaker will be and when the next utterance will occur—have been receiving a lot of attention in recent research. To build a model for predicting these behaviors we conducted a research study to determine whether respiration could be effectively used as a basis for the prediction. Results of analyses of utterance and respiration data collected from participants in multiparty meetings reveal that the speaker takes a breath more quickly and deeply after the end of an utterance in turn-keeping than in turn-changing. They also indicate that the listener who will be the next speaker takes a bigger breath more quickly and deeply in turn-changing than the other listeners. On the basis of these results, we constructed and evaluated models for predicting the next speaker and the time of the next utterance in multiparty meetings. The results of the evaluation suggest that the characteristics of the speaker's inhalation right after an utterance unit—the points in time at which the inhalation starts and ends after the end of the utterance unit and the amplitude, slope, and duration of the inhalation phase—are effective for predicting the next speaker in multiparty meetings. They further suggest that the characteristics of listeners' inhalation—the points in time at which the inhalation starts and ends after the end of the utterance unit and the minimum and maximum inspiration, amplitude, and slope of the inhalation phase—are effective for predicting the next speaker. The start time and end time of the next speaker's inhalation are also useful for predicting the time of the next utterance in turn-changing.

Prediction of Who Will Be the Next Speaker and When Using Gaze Behavior in Multiparty Meetings

In multiparty meetings, participants need to predict the end of the speaker’s utterance and who will start speaking next, as well as consider a strategy for good timing to speak next. Gaze behavior plays an important role in smooth turn-changing. This article proposes a prediction model that features three processing steps to predict (I) whether turn-changing or turn-keeping will occur, (II) who will be the next speaker in turn-changing, and (III) the timing of the start of the next speaker’s utterance. For the feature values of the model, we focused on gaze transition patterns and the timing structure of eye contact between a speaker and a listener near the end of the speaker’s utterance. Gaze transition patterns provide information about the order in which gaze behavior changes. The timing structure of eye contact is defined as who looks at whom and who looks away first, the speaker or listener, when eye contact between the speaker and a listener occurs. We collected corpus data of multiparty meetings, using the data to demonstrate relationships between gaze transition patterns and timing structure and situations (I), (II), and (III). The results of our analyses indicate that the gaze transition pattern of the speaker and listener and the timing structure of eye contact have a strong association with turn-changing, the next speaker in turn-changing, and the start time of the next utterance. On the basis of the results, we constructed prediction models using the gaze transition patterns and timing structure. The gaze transition patterns were found to be useful in predicting turn-changing, the next speaker in turn-changing, and the start time of the next utterance. Contrary to expectations, we did not find that the timing structure is useful for predicting the next speaker and the start time. This study opens up new possibilities for predicting the next speaker and the timing of the next utterance using gaze transition patterns in multiparty meetings.

Clonal Deletion Established via Invariant NKT Cell Activation and Costimulatory Blockade Requires In Vivo Expansion of Regulatory T Cells

Recently, the immune-regulating potential of invariant natural killer T (iNKT) cells has attracted considerable attention. We previously reported that a combination treatment with a liposomal ligand for iNKT cells and an anti-CD154 antibody in a sublethally irradiated murine bone marrow transplant (BMT) model resulted in the establishment of mixed hematopoietic chimerism through in vivo expansion of regulatory T cells (Tregs). Herein, we show the lack of alloreactivity of CD8(+) T cells in chimeras and an early expansion of donor-derived dendritic cells (DCs) in the recipient thymi accompanied by a sequential reduction in the donor-reactive Vβ-T cell receptor repertoire, suggesting a contribution of clonal deletion in this model. Since thymic expansion of donor DCs and the reduction in the donor-reactive T cell repertoire were precluded with Treg depletion, we presumed that Tregs should preform before the establishment of clonal deletion. In contrast, the mice thymectomized before BMT failed to increase the number of Tregs and to establish CD8(+) T cell tolerance, suggesting the presence of mutual dependence between the thymic donor-DCs and Tregs. These results provide new insights into the regulatory mechanisms that actively promote clonal deletion.

The evaluation of diastolic function using the diastolic wall strain (DWS) before and after radical surgery for congenital diaphragmatic hernia

OBJECTIVE

The measurement of diastolic wall strain (DWS), a new method of evaluating cardiac diastolic function, was employed to evaluate ventricular diastolic function in patients with congenital diaphragmatic hernia (CDH).

MATERIALS AND METHODS

Eighteen neonates with a CDH who were born and treated in our hospital between September 2009 and January 2013 were studied. The left ventricular posterior wall thickness during the systolic phase (PWs) and diastolic (PWd) phase was measured using M-mode imaging, and the DWS was calculated as (PWs-PWd)/PWs. The Tei index, the isovolumic relaxation time (IRT), and the fraction shortening (FS) were measured as indices of cardiac function in 14, 15, and 18 cases, respectively. Cardiac function was measured before and after surgery. Statistical analyses were performed using the paired t test.

RESULTS

The pre- and postoperative DWS, Tei index, IRT and FS values were 0.19 ± 0.06 and 0.26 ± 0.11 (P < 0.01), 0.40 ± 0.12 and 0.31 ± 0.11 (P < 0.05), 48 ± 14 and 39 ± 5.0 ms (P < 0.05), 30 ± 7.7 and 34 ± 7.4 % (P < 0.05), respectively.

CONCLUSION

The diastolic and systolic functions were not only measured by the Tei index, IRT and FS values, but also by the DWS value, which improved after surgery. The measurement of DWS is an easy and useful method for evaluating the diastolic function of CDH patients.

Prognosis in tetralogy of Fallot with absent pulmonary valve

BACKGROUND

Tetralogy of Fallot with absent pulmonary valve (TF/APV) is a rare and severe congenital heart disease with high mortality. The aim of this study was to assess whether TF/APV prognosis is related to fetal and postnatal clinical course and pulmonary artery (PA) configuration.

METHODS

The fetal and postnatal echocardiograms and clinical outcomes of 13 patients with TF/APV (diagnosed antenatally in 9 patients and postnatally in 4) were reviewed, and divided into two groups: group A (n = 6), alive; and group D (n = 7), dead.

RESULTS

Fetal period: group A, polyhydramnios n = 0, hydrops fetalis (HF) n = 0, patent ductus arteriosus (PDA) n = 2; group D, polyhydramnios n = 3, HF n = 2, PDA n = 0. Postnatal period: group A, five patients underwent intracardiac repair, including one requiring artificial ventilation (AV). A further AV patient required three operations before extubation. Postoperative courses were all good. Group D, excluding the two intrauterine fetal deaths, four patients required AV (three of whom died neonatally or in early childhood) and one underwent intracardiac repair. PA configuration: all group A patients had bulbous expansion of left and right PA (clover type). Three patients in group D had bulbous expansion of main PA (balloon type).

CONCLUSIONS

PDA was a factor associated with good prognosis. Hydramnion and HF were factors associated with poor prognosis. Given that there was a higher rate of postnatal AV and poorer prognosis in balloon type than in clover type PA (P < 0.05), PA configuration is also considered an important factor to predict postnatal outcome in TF/APV.

Influence of surface treatment of contaminated zirconia on surface free energy and resin cement bonding

Influences of contamination and cleaning methods on the bonding of resin cement to zirconia ceramics were examined. Airborne particle-abraded zirconia (IPS e.max ZirCAD) specimens were contaminated with saliva and cleaned with tap water (SC) or by application of 37% phosphoric acid (PA), Ivoclean (IC), or additional airborne particle abrasion (AB). Specimens without contamination served as controls. After application of Monobond Plus to the surface of the specimens, resin cement was mixed and inserted into a mold. Surface free energies of the specimens were determined by measuring contact angles. Surface treatment and storage conditions significantly influenced bond strength, while there was no significant interaction between the two factors. Surface free energies of the SC and IC groups were significantly lower than those of the other groups. Additional AB of saliva-contaminated zirconia increased the strength of bonding with the resin cement as well as increased surface free energy.