Transient stabilization of human cardiovascular progenitor cells from hPSCs in vitro reflects stage-specific heart development in vivo.

AIM: Understanding the molecular identity of human pluripotent stem cell (hPSC)-derived cardiac progenitors and mechanisms controlling their proliferation and differentiation, is valuable for developmental biology and regenerative medicine. METHODS AND RESULTS: Here we show that chemical modulation of Histone Acetyl Transferases (HATs; by IQ-1) and WNT (by CHIR99021), synergistically enable the transient and reversible block of directed cardiac differentiation progression on hPSCs. The resulting stabilized cardiovascular progenitors (SCPs) are characterized by ISL1pos/KI-67pos/NKX2-5neg expression. In the presence of the chemical inhibitors, SCPs maintain a proliferation quiescent state. Upon small molecules removal SCPs resume proliferation and concomitant NKX2-5 upregulation triggers cell-autonomous differentiation into cardiomyocytes. Directed differentiation of SCPs into the endothelial and smooth muscle lineages confirms their full developmental potential typical of bona fide cardiovascular progenitors. Single-cell RNAseq-based transcriptional profiling of our in vitro generated human SCPs notably reflects the dynamic cellular composition of E8.25-E9.25 posterior second heart field (pSHF) of mouse hearts, hallmarked by NR2F2 expression. Investigating molecular mechanisms of SCP stabilization, we found that the cell-autonomously regulated Retinoic Acid (RA) and BMP signaling is governing SCPs transition from quiescence towards proliferation and cell-autonomous differentiation, reminiscent of a niche-like behavior. CONCLUSION: The chemically defined and reversible nature our stabilization approach provides an unprecedented opportunity to dissect mechanisms of cardiovascular progenitors' specification and reveal their cellular and molecular properties.

Low-Loss Dielectric Ink for Printed Radio Frequency and Microwave Devices.

Direct write printing is restricted by the lack of dielectric materials that can be printed with high resolution and offer dissipation factors at radio frequency (RF) within the range of commercial RF laminates. Herein, we outline the development of dielectric materials with dielectric loss below 0.006 in X and Ku frequency bands (8.2-18 GHz), the range required for radio frequency and microwave applications. The described materials were designed for printability and processability, specifically a prolonged viscosity below 1000 cps and a robust cure procedure, which requires minimal heat treatment. In the first stage of this work, nonpolar ring-opening metathesis polymerization (ROMP) is demonstrated at room temperature in an open-air environment with a low-viscosity monomer, 5-vinyl-2-norbornene, using the second-generation Grubbs catalyst (G-II). Differential scanning calorimetry (DSC) was used to study how the catalyst activity is increased with heating at various stages in the reaction, which is then used as a strategy to cure the material after printing. The resulting cured poly(5-vinyl-2-norbornene) material is then characterized for dielectric and mechanical performance before and after a secondary heat treatment, which mimics processing procedures to incorporate subsequent printed conductor layers for multilayer applications. After the secondary heat treatment, the material exhibits a 55.0% reduction in the coefficient of thermal expansion (CTE), an increase in glass-transition temperature (Tg) from 32.4 to 46.1 °C, and an increased 25 °C storage modulus from 428 to 1031 MPa while demonstrating a minimal change in dielectric loss. Lastly, samples of the developed dielectric material are printed with silver overtop to demonstrate how the material can be effectively incorporated into fully printed, multilayer RF applications.

Teen, Queer, and Asian: Lesbian, Gay, Bisexual, Transgender, Queer, Plus Asian American Students' Experiences in Schools.

BACKGROUND: The experiences of youth with intersecting LGBTQ+ and Asian American (AA) identities have been largely unexplored. This study explored these experiences of LGBTQ+ AA California youth with mental health, school climate, and school victimization. METHODS: Drawing from the 2016-2017 California Healthy Kids Survey (N = 326,124), this study utilized secondary data analyses to examine mental health, school climate, and school victimization among students of specific AA ethnicities (eg, Cambodian, Hmong, Vietnamese) and LGBTQ+ identities. The participants in this study included 7th, 9th, and 11th graders from California public schools, with subsamples of lesbian or gay students (N = 13,291), bisexual students (N = 30,127), and transgender students (N = 7916). RESULTS: The results indicated that Asian Indian, Cambodian, Hmong, Japanese, Korean, Laotian, and Other Asian LGBTQ+ students experienced more negative school climate and victimization compared to their Chinese, Filipino, Vietnamese, and white LGBTQ+ peers. For instance, 41.1% of Cambodian transgender students reported they were beaten up compared to 27.1% of white transgender students. Mental health differences between LGBTQ+ AA and LGBTQ+ white students were also found. CONCLUSIONS: This study's findings can inform school administrators and teachers how to best support LGBTQ+ AA populations.

The impact of hypoxia on B cells in COVID-19

Prominent early features of COVID-19 include severe, often clinically silent, hypoxia and a pronounced reduction in B cells, the latter important in defence against SARS-CoV-2. This brought to mind the phenotype of mice with VHL-deficient B cells, in which Hypoxia-Inducible Factors are constitutively active, suggesting hypoxia might drive B cell abnormalities in COVID-19. We demonstrated the breadth of early and persistent defects in B cell subsets in moderate/severe COVID-19, including reduced marginal zone-like, memory and transitional B cells, changes we also observed in B cell VHL-deficient mice. This was corroborated by hypoxia-related transcriptional changes in COVID-19 patients, and by similar B cell abnormalities in mice kept in hypoxic conditions, including reduced marginal zone and germinal center B cells. Thus hypoxia might contribute to B cell pathology in COVID-19, and in other hypoxic states. Through this mechanism it may impact on COVID-19 outcome, and be remediable through early oxygen therapy.

The cellular immune response to COVID-19 deciphered by single cell multi-omics across three UK centres

The COVID-19 pandemic, caused by SARS coronavirus 2 (SARS-CoV-2), has resulted in excess morbidity and mortality as well as economic decline. To characterise the systemic host immune response to SARS-CoV-2, we performed single-cell RNA-sequencing coupled with analysis of cell surface proteins, providing molecular profiling of over 800,000 peripheral blood mononuclear cells from a cohort of 130 patients with COVID-19. Our cohort, from three UK centres, spans the spectrum of clinical presentations and disease severities ranging from asymptomatic to critical. Three control groups were included: healthy volunteers, patients suffering from a non-COVID-19 severe respiratory illness and healthy individuals administered with intravenous lipopolysaccharide to model an acute inflammatory response. Full single cell transcriptomes coupled with quantification of 188 cell surface proteins, and T and B lymphocyte antigen receptor repertoires have provided several insights into COVID-19: 1. a new non-classical monocyte state that sequesters platelets and replenishes the alveolar macrophage pool; 2. platelet activation accompanied by early priming towards megakaryopoiesis in immature haematopoietic stem/progenitor cells and expansion of megakaryocyte-primed progenitors; 3. increased clonally expanded CD8+ effector:effector memory T cells, and proliferating CD4+ and CD8+ T cells in patients with more severe disease; and 4. relative increase of IgA plasmablasts in asymptomatic stages that switches to expansion of IgG plasmablasts and plasma cells, accompanied with higher incidence of BCR sharing, as disease severity increases. All data and analysis results are available for interrogation and data mining through an intuitive web portal. Together, these data detail the cellular processes present in peripheral blood during an acute immune response to COVID-19, and serve as a template for multi-omic single cell data integration across multiple centers to rapidly build powerful resources to help combat diseases such as COVID-19.

Arteritis and Large Vessel Occlusive Strokes in Children After COVID-19 Infection.

We describe 2 previously healthy children who suffered disabling arterial ischemic strokes because of acute intracranial large vessel occlusion within 3 to 4 weeks of coronavirus disease 2019 (COVID-19) infection. Both children presented from communities with high COVID-19 case rates in the Southwest United States. An 8-year-old American Indian girl experienced severe iron deficiency anemia requiring blood transfusion and presented with bilateral middle cerebral artery (MCA) distribution strokes 3 weeks later. She underwent emergent mechanical thrombectomy of the left MCA with successful clot retrieval but experienced reocclusion of that artery 5 hours after intervention. She also had evidence of cerebral arteritis on catheter angiography and vessel wall imaging, and clot pathology revealed recently formed, unorganized platelet- and fibrin-rich thrombus with sparse clusters of erythrocytes, degenerated histiocytes, few eosinophils, and rare neutrophils. A 16-year old African American boy demonstrated evidence of arteritis on brain magnetic resonance angiography and serological markers of cardiac and renal injury accompanied by positive lupus anticoagulant antibodies. The children described in this report express clinical features inconsistent with focal cerebral arteriopathy, including elevated markers of systemic inflammation in both bilateral MCA strokes in one case and multiple organ system dysfunction in the other case. Neither patient fulfilled criteria for multisystem inflammatory syndrome in children, given absence of fever. These cases illustrate that systemic postinfectious arteritis with cerebrovascular involvement may complicate COVID-19 infection in previously healthy school-aged children, and their presentations may overlap but not fulfill criteria for multisystem inflammatory syndrome in children or focal cerebral arteriopathy.

Modeling COVID-19: Forecasting and analyzing the dynamics of the outbreak in Hubei and Turkey

As the pandemic of Coronavirus Disease 2019 (COVID-19) rages throughout the world, accurate modeling of the dynamics thereof is essential. However, since the availability and quality of data varies dramatically from region to region, accurate modeling directly from a global perspective is difficult, if not altogether impossible. Nevertheless, via local data collected by certain regions, it is possible to develop accurate local prediction tools, which may be coupled to develop global models. In this study, we analyze the dynamics of local outbreaks of COVID-19 via a coupled system of ordinary differential equations (ODEs). Utilizing the large amount of data available from the ebbing outbreak in Hubei, China as a testbed, we estimate the basic reproductive number,[R] 0 of COVID-19 and predict the total cases, total deaths, and other features of the Hubei outbreak with a high level of accuracy. Through numerical experiments, we observe the effects of quarantine, social distancing, and COVID-19 testing on the dynamics of the outbreak. Using knowledge gleaned from the Hubei outbreak, we apply our model to analyze the dynamics of outbreak in Turkey. We provide forecasts for the peak of the outbreak and the total number of cases/deaths in Turkey, for varying levels of social distancing, quarantine, and COVID-19 testing.

A novel technique for inferior vena cava filter extraction.

Inferior vena cava (IVC) filters are used to protect against pulmonary embolism in high-risk patients. Whilst the insertion of retrievable IVC filters is gaining popularity, a proportion of such devices cannot be removed using standard techniques. We describe a novel approach for IVC filter removal that involves snaring the filter superiorly along with the use of flexible forceps or laser devices to dissect the filter struts from the caval wall. This technique has used to successfully treat three patients without complications in whom standard techniques failed.

Juvenile Huntington disease exacerbated by methylphenidate: case report.

The authors describe the case of an 8-year-old boy, otherwise healthy, who presented with symptoms consistent with attention-deficit hyperactivity disorder (ADHD) and was started on a trial of methylphenidate. Within 4 weeks, he experienced a rapid decline in fine motor skills, with dysarthria, intention tremor, motor impersistence, and diffusely increased tone. Symptoms persisted despite cessation of methylphenidate. At that time, a paternal history of Huntington disease was disclosed. Molecular analysis revealed an expansion in CAG repeats to 75 copies, within the range characteristic of juvenile Huntington disease. This report raises the possibility that use of dopaminergic agonists in patients with a family history of Huntington disease may lead to clinical exacerbation of motor symptoms and/or unwitting diagnosis in an unprepared family.

Intra individual variability in markers of proteinuria for normal subjects and those with cadmium induced renal dysfunction: interpretation of results from untimed, random urine samples.

The project aimed to help interpretation of urinary protein measurements, namely -2-microglobulin, retinol-binding protein, albumin and total protein in untimed, random urine samples as indicating significant changes in renal tubular reabsorption and glomerular permeability in an individual. A standard methodology used in clinical laboratory medicine was applied to calculate the intra-individual biological variation for these analytes. This parameter in conjunction with a laboratory's analytical variation allows definition of uncertainty about a single urine protein measurement, significant changes above normal variation in serial measurements within an individual and a defined level of maximum acceptable analytical imprecision. Repeat urine samples were obtained over a period of one week from a group of cadmium-exposed workers, 90% of whom had long-term tubular proteinuria, and a group of five unexposed volunteers with normal renal function. Dilute samples defined as having creatinines less than 3 mmol l-1 were excluded, as were urines with pH less than 5.5 for -2-microglobulin. Samples were analysed twice after randomisation in large batches. There was no evidence of any diurnal variation in the four protein measurements from samples collected between early morning and 16:00 hours. Creatinine or specific gravity correction of urine results for all four proteins only marginally reduced the uncertainty associated with an individual measurement asreflecting the true excretion value. For those subjects with defined tubular proteinuria, variability in retinol-binding protein excretion was less than that for -2- microglobulin. About 30% of the samples had urine pHs of 5.5 or less where -2- microglobulin degradation occurs. Using our laboratory analytical precision the minimum changes between serial creatinine-corrected measurements that are needed to be considered statistically significant (p < 0.05) is 110% for retinol-binding protein, 177% for -2-microglobulin, 70% for total protein, and 81% for albumin. Unlike published data for cadmium and mercury, the use of creatinine or specific gravity correction of random untimed urine samples for the urinary proteins does not make a large improvement to the interpretation of data by reducing the uncertainty associated with a measurement. There are significant advantages to the use of retinol-binding protein in contrast to -2- microglobulin as an indicator of renal tubular damage. Levels for defined acceptable analytical precision are calculated for laboratories undertaking protein estimations. The data in this report will help in the interpretation of urinary protein measurements without monitoring cadmium workers.