NuMA assemblies organize microtubule asters to establish spindle bipolarity in acentrosomal human cells.

In most animal cells, mitotic spindle formation is mediated by coordination of centrosomal and acentrosomal pathways. At the onset of mitosis, centrosomes promote spindle bipolarization. However, the mechanism through which the acentrosomal pathways facilitate the establishment of spindle bipolarity in early mitosis is not completely understood. In this study, we show the critical roles of nuclear mitotic apparatus protein (NuMA) in the generation of spindle bipolarity in acentrosomal human cells. In acentrosomal human cells, we found that small microtubule asters containing NuMA formed at the time of nuclear envelope breakdown. In addition, these asters were assembled by dynein and the clustering activity of NuMA. Subsequently, NuMA organized the radial array of microtubules, which incorporates Eg5, and thus facilitated spindle bipolarization. Importantly, in cells with centrosomes, we also found that NuMA promoted the initial step of spindle bipolarization in early mitosis. Overall, these data suggest that canonical centrosomal and NuMA-mediated acentrosomal pathways redundantly promote spindle bipolarity in human cells.

Echocardiographic score for the screening of cardiac amyloidosis with positive 99m technetium pyrophosphate scintigraphy result.

INTRODUCTION: Speckle-tracking-derived strains in cardiac chambers may provide better solutions for transthyretin amyloid cardiomyopathy (ATTR-CM) screening. This study aimed to evaluate the efficacy of biventricular strain measurements using speckle tracking for screening 99m Tc-pyrophosphate (99m Tc-PYP) scintigraphy-positive cardiomyopathy, which is nearly equivalent to ATTR-CM. METHODS: We performed a retrospective analysis of transthoracic echocardiographic studies using vendor-independent speckle tracking analysis in older patients (≥65 years) who underwent 99m Tc-PYP scintigraphy to evaluate the etiology of suspected ATTR-CM in our institute between January 2019 and December 2022. RESULTS: The entire cohort (n = 89) was divided into two subgroups positive 99m Tc-PYP scan results (n = 34) and negative 99m Tc-PYP scan results (n = 55). In the multivariate analysis, posterior wall thickness (p = .003, odds ratio [OR]:1.48, 95% confidence interval [CI]:1.14 -1.92), left ventricular longitudinal strain apical/basal ratio (LVLSapi/bas) (p = .015, OR: 2.78, 95% CI: 1.23-6.32, and right ventricular longitudinal strain (RVLS) (p = .003, OR: 1.15, 95% CI: 1.05 -1.26) were selected to be the most representative echocardiographic findings in 99m Tc-PYP positive cardiomyopathy. The receiver operating characteristic analysis indicated that posterior wall thickness (p < .0001, area under the curve [AUC]: .821, cut-off value: 14.0 mm), LVLSapi/bas (p < .001, AUC: .802, cut-off value: 2,16), and RVLS (p < .001, AUC: .791, cut-off value: -18.7%) could significantly detect 99m Tc-PYP positive results with an excellent credibility. Echocardiographic score points calculated using the summary of these three parameters in each patient revealed that a 2-point score had a fair sensitivity (85%) and an excellent specificity (93%), while a 1-point score had an excellent sensitivity (91%) and a modest specificity (53%). CONCLUSION: Our proposed echocardiographic screening tool for 99m Tc-PYP scintigraphy-positive cardiomyopathy may help clinicians manage patients with suspected ATTR-CM.

The centriole protein CEP76 negatively regulates PLK1 activity in the cytoplasm for proper mitotic progression.

Polo-like kinase 1 (PLK1) dynamically changes its localization and plays important roles in proper mitotic progression. In particular, strict control of cytoplasmic PLK1 is needed to prevent mitotic defects. However, the regulation of cytoplasmic PLK1 is not fully understood. In this study, we show that CEP76, a centriolar protein, physically interacts with PLK1 and tightly controls the activation of cytoplasmic PLK1 during mitosis in human cells. We found that removal of centrosomes induced ectopic aggregation of PLK1, which is highly phosphorylated, in the cytoplasm during mitosis. Importantly, a targeted RNAi screen revealed that depletion of CEP76 resulted in a similar phenotype. In addition, depletion of CEP76 caused defective spindle orientation and mitotic delay. Moreover, the formation of ectopic PLK1 aggregates and defective spindle orientation were significantly suppressed by the inhibition of PLK1 kinase activity. Overall, these results demonstrate that CEP76 suppresses the aberrant activation of cytoplasmic PLK1 for proper mitotic progression.This article has an associated First Person interview with the first author of the paper.

Influence of pulmonary ventilation rate and breathing cycle period on the risk of cross-infection.

This study examined the characteristics of the exhaled airflow pattern and breathing cycle period of human subjects and evaluated the influence of pulmonary ventilation rate and breathing cycle period on the risk of cross-infection. Measurements with five human subjects and a breathing thermal manikin were performed, and the peak exhaled airflow velocity from the mouth and the breathing cycle period were measured. Experiments on cross-infection between two breathing thermal manikins were then conducted in a full-scale test room, in which the pulmonary ventilation rate and breathing cycle period were varied systematically. Both peak flow velocity and breathing cycle length varied considerably between different subjects. The breathing cycle period in a standing posture was 18.9% lower than in a sitting posture. The influence of pulmonary ventilation rate and breathing cycle period extended up to a separation distance of 1.0 m between the two manikins. Increasing the pulmonary ventilation rate of the exposed person greatly increased the risk of cross-infection. Decreasing the breathing cycle period from the widely used "6 second" value led to a considerable increase in the risk of cross-infection. Standing posture resulted in a higher risk of cross-infection than sitting posture.

Airborne transmission between room occupants during short-term events: Measurement and evaluation.

This study experimentally examines and compares the dynamics and short-term events of airborne cross-infection in a full-scale room ventilated by stratum, mixing and displacement air distributions. Two breathing thermal manikins were employed to simulate a standing infected person and a standing exposed person. Four influential factors were examined, including separation distance between manikins, air change per hour, positioning of the two manikinsand air distribution. Tracer gas technique was used to simulate the exhaled droplet nuclei from the infected person and fast tracer gas concentration meters (FCM41) were used to monitor the concentrations. Real-time and average exposure indices were proposed to evaluate the dynamics of airborne exposure. The time-averaged exposure index depends on the duration of exposure time and can be considerably different during short-term events and under steady-state conditions. The exposure risk during short-term events may not always decrease with increasing separation distance. It changes over time and may not always increase with time. These findings imply that the control measures formulated on the basis of steady-state conditions are not necessarily appropriate for short-term events.

Vericiguat and transcatheter edge-to-edge mitral valve repair for combined post- and pre-capillary pulmonary hypertension due to left ventricular low ejection fraction and functional mitral regurgitation.

A 66-year-old female was diagnosed with combined post- and pre-capillary pulmonary hypertension due to heart failure with reduced ejection fraction (47 %) and functional mitral regurgitation [mean pulmonary arterial wedge pressure: 27 mmHg; pulmonary arterial pressure: 91/30 (56) mmHg; pulmonary vascular resistance: 12.9 Wood units; and cardiac index: 1.77 L/min/m2]. Following treatment with vericiguat (a novel oral soluble guanylate cyclase stimulator), hemodynamics improved [mean pulmonary arterial wedge pressure: 27 mmHg; pulmonary arterial pressure: 54/26 (35) mmHg; pulmonary vascular resistance: 2.2 Wood units; and cardiac index: 2.80 L/min/m2]. Therefore, transcatheter edge-to-edge repair for functional mitral regurgitation was performed. One month later, further improvement in hemodynamics was confirmed. Learning objective: Vericiguat (a novel oral soluble guanylate cyclase stimulator) and transcatheter edge-to-edge mitral valve repair may improve combined post- and pre-capillary pulmonary hypertension due to low ejection fraction of the left ventricle and functional mitral regurgitation.

Incremental Value of Global Longitudinal Strain for Confirming Heart Failure-Related Symptoms in Severe Aortic Stenosis.

The indications or timing of aortic valve replacement for symptomatic aortic stenosis (AS) are based on a patient's life expectancy and symptoms. However, clinical decision-making may be difficult because symptoms are subjective and cannot be quantitatively assessed and confirmed. This study aimed to evaluate the association between heart failure (HF)-related symptoms and cardiac hemodynamic left ventricular deformations in patients with severe AS using transthoracic echocardiographic assessments of left ventricular global longitudinal strain (LV-GLS). The medical records of patients hospitalized for AS between February 2017 and September 2019 were retrospectively screened. Independent cardiologists analyzed the transthoracic echocardiographic images of a digital echocardiography database. The cohort comprised 177 hospitalized patients with severe AS and no history of HF. The subgroup with HF-related symptoms included 87 patients, whereas that without HF-related symptoms included 90 patients. In 145 patients without atrial fibrillation, the left atrial volume index (LAVI) and LV-GLS were significantly associated with HF-related symptoms (odds ratio 1.033, 95% confidence interval 1.008 to 1.059, p = 0.011 and odds ratio 1.224, 95% confidence interval 1.118 to 1.340, p <0.0001, respectively). Moreover, the combination of brain natriuretic peptide level, LAVI, and LV-GLS showed better diagnostic accuracy than the combination of brain natriuretic peptide level and LAVI (p = 0.005). However, there were no such tendencies in 32 patients with atrial fibrillation. The HF-related symptoms in patients with severe AS were strongly linked to LV-GLS. LV-GLS showed incremental value for confirming HF-related symptoms.

Feasibility and Outcome of Transjugular Intracardiac Echocardiography-Guided Transcatheter Aortic Valve Replacement.

Background: There are limited data on the impact of intracardiac echocardiography (ICE)-guided transcatheter aortic valve replacement (TAVR) on the new permanent pacemaker implantation (PPMI) rate. Objectives: This study investigated the feasibility and outcome of transjugular ICE (TJ-ICE) -guided TAVR, by visualizing the relationship between the membranous septum (MS) and the transcatheter aortic valve (TAV). Methods: Among patients with severe aortic stenosis who underwent TAVR between February 2017 and June 2020, this study enrolled a total of 163 patients with TJ-ICE-guided TAVR. MS length was measured by ICE. The primary endpoint of this study was the incidence of new PPMI at 30 days. Results: The mean age of the patients in this study was 84.9 ± 4.6 years, and 71.2% of the patients were female. Device success was 96.3% with TJ-ICE guidance. A TJ-ICE-related complication occurred in 1 case (0.6%). The median length of the MS was 5.8 mm (IQR: 5.0-6.9 mm). Excellent intraobserver (intraclass correlation coefficient [ICC]: 0.94; 95% CI:0.79-0.98; P < 0.001) and interobserver (ICC: 0.93; 95% CI: -0.05 to 0.98; P < 0.001) agreements were shown. The new PPMI rate was 6.7% at 30 days without a significant difference between balloon-expandable valves and self-expandable valves (3.4% vs 8.7%; P = 0.226). Patients with a TAV implantation depth less than MS length had a significantly lower incidence of new PPMI compared with patients with a TAV implantation depth greater than MS length (2.1% vs 13.4%; P = 0.005), regardless of baseline right bundle branch block presence (6.7% vs 66.7%; P = 0.004) or absence (1.2% vs 8.2%; P = 0.041). Conclusions: TJ-ICE-guided TAVR demonstrated remarkable feasibility and safety. The TJ-ICE-guided final TAV position had a significant impact on the new PPMI rate. (Tokai Valve Registry; UMIN000036671).

Centriole and PCM cooperatively recruit CEP192 to spindle poles to promote bipolar spindle assembly.

The pericentriolar material (PCM) that accumulates around the centriole expands during mitosis and nucleates microtubules. Here, we show the cooperative roles of the centriole and PCM scaffold proteins, pericentrin and CDK5RAP2, in the recruitment of CEP192 to spindle poles during mitosis. Systematic depletion of PCM proteins revealed that CEP192, but not pericentrin and/or CDK5RAP2, was crucial for bipolar spindle assembly in HeLa, RPE1, and A549 cells with centrioles. Upon double depletion of pericentrin and CDK5RAP2, CEP192 that remained at centriole walls was sufficient for bipolar spindle formation. In contrast, through centriole removal, we found that pericentrin and CDK5RAP2 recruited CEP192 at the acentriolar spindle pole and facilitated bipolar spindle formation in mitotic cells with one centrosome. Furthermore, the perturbation of PLK1, a critical kinase for PCM assembly, efficiently suppressed bipolar spindle formation in mitotic cells with one centrosome. Overall, these data suggest that the centriole and PCM scaffold proteins cooperatively recruit CEP192 to spindle poles and facilitate bipolar spindle formation.

Mechanisms of spindle bipolarity establishment in acentrosomal human cells.

Centrosomes are not absolutely essential for cell division; acentrosomal bipolar spindles can be established in oocytes and centrosome-eliminated somatic cells. However, the detailed mechanisms describing how spindle bipolarity is established without centrosomes are not completely understood. We have recently demonstrated that in acentrosomal human cells, nuclear mitotic apparatus protein (NuMA) assemblies-mediated microtubule asters and EG5 promote spindle bipolarization in early mitosis.