Transmembrane protein 150b attenuates BMP signaling in the Xenopus organizer

The vertebrate organizer is a specified embryonic tissue that regulates dorsoventral patterning and axis formation. Although numerous cellular signaling pathways have been identified as regulators of the organizer's dynamic functions, the process remains incompletely understood, and as-yet unknown pathways remain to be explored for sophisticated mechanistic understanding of the vertebrate organizer. To identify new potential key factors of the organizer, we performed complementary DNA (cDNA) microarray screening using organizer-mimicking Xenopus laevis tissue. This analysis yielded a list of prospective organizer genes, and we determined the role of six-transmembrane domain containing transmembrane protein 150b (Tmem150b) in organizer function. Tmem150b was expressed in the organizer region and induced by Activin/Nodal signaling. In X. laevis, Tmem150b knockdown resulted in head defects and a shortened body axis. Moreover, Tmem150b negatively regulated bone morphogenetic protein (BMP) signaling, likely via physical interaction with activin receptor-like kinase 2 (ALK2). These findings demonstrated that Tmem150b functions as a novel membrane regulatory factor of BMP signaling with antagonistic effects, contributing to the understanding of regulatory molecular mechanisms of organizer axis function. Investigation of additional candidate genes identified in the cDNA microarray analysis could further delineate the genetic networks of the organizer during vertebrate embryogenesis.

Assessment of thirty-day readmission rate, timing, causes and predictors after hospitalization with COVID-19

BACKGROUND

There are limited data on the characteristics of 30-day readmission after hospitalization with coronavirus disease 2019 (COVID-19).

OBJECTIVES

To examine the rate, timing, causes, predictors and outcomes of 30-day readmission after COVID-19 hospitalization.

METHODS

From 13 March to 9 April 2020, all patients hospitalized with COVID-19 and discharged alive were included in this retrospective observational study. Multivariable logistic regression was used to identify the predictors of 30-day readmission, and a restricted cubic spline function was utilized to assess the linearity of the association between continuous predictors and 30-day readmission.

RESULTS

A total of 1062 patients were included in the analysis, with a median follow-up time of 62 days. The mean age of patients was 56.5 years, and 40.5% were women. At the end of the study, a total of 48 (4.5%) patients were readmitted within 30 days of discharge, and a median time to readmission was 5 days. The most common primary diagnosis of 30-day readmission was a hypoxic respiratory failure (68.8%) followed by thromboembolism (12.5%) and sepsis (6.3%). The patients with a peak serum creatinine level of ≥1.29 mg/dL during the index hospitalization, compared to those with a creatinine of <1.29 mg/dL, had 2.4 times increased risk of 30-day readmission (adjusted odds ratio: 2.41; 95% CI: 1.23-4.74). The mortality rate during the readmission was 22.9%.

CONCLUSION

With 4.5% of the thirty-day readmission rate, COVID-19 survivors were readmitted early after hospital discharge, mainly due to morbidities of COVID-19. One in five readmitted COVID-19 survivors died during their readmission.

Incidence, risk factors, and fracture healing of atypical femoral fractures: a multicenter case-control study

The incidence of atypical femoral fractures (AFFs) was 2.95% among 6644 hip and femoral fractures. Independent risk factors included the use of bisphosphonates (BPs), osteopenia or osteoporosis, rheumatoid arthritis, increased femoral curvatures, and thicker femoral cortices. Patients with AFFs and BP treatment were more likely to have problematic healing than those with typical femoral fractures (TFFs) and no BP treatment.

INTRODUCTION

To determine the incidence and risk factors of atypical femoral fractures (AFFs), we performed a multicenter case-control study. We also investigated the effects of bisphosphonates (BPs) on AFF healing.

METHODS

We retrospectively reviewed the medical records and radiographs of 6644 hip and femoral fractures of patients from eight tertiary referral hospitals. All the radiographs were reviewed to distinguish AFFs from TFFs. Univariate and multivariate logistic regression analyses were performed to identify risk factors, and interaction analyses were used to investigate the effects of BPs on fracture healing.

RESULTS

The incidence of AFFs among 6644 hip and femoral fractures was 2.95% (90 subtrochanter and 106 femoral shaft fractures). All patients were females with a mean age of 72 years, and 75.5% were exposed to BPs for an average duration of 5.2 years (range, 1-17 years). The use of BPs was significantly associated with AFFs (p < 0.001, odds ratio = 25.65; 95% confidence interval = 10.74-61.28). Other independent risk factors for AFFs included osteopenia or osteoporosis, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex at the shaft level. Interaction analyses showed that patients with AFFs using BPs had a significantly higher risk of problematic fracture healing than those with TFFs and no BP treatment.

CONCLUSIONS

The incidence of AFFs among 6644 hip and femoral fractures was 2.95%. Osteopenia or osteoporosis, use of BPs, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex were independent risk factors for the development of AFFs. Patients with AFFs and BP treatment were more likely to have problematic fracture healing than those with TFFs and no BP treatment.

In-hospital infective endocarditis following transcatheter aortic valve replacement: a cross-sectional study of the National Inpatient Sample database in the USA

BACKGROUND

While the utilization of transcatheter aortic valve replacement (TAVR) for patients with severe aortic stenosis has been increasing, in-hospital infective endocarditis (IE) following TAVR has not been well described.

AIM

To identify in-hospital IE following TAVR.

METHODS

All patients who underwent TAVR between 2012 and 2014 were identified using the National Inpatient Sample database. Multi-variate logistic regression was performed to identify the predictors of in-hospital IE after TAVR.

FINDINGS

Of the 41,025 patients who received TAVR, 120 patients (0.3%) developed in-hospital IE. Viridans group streptococci (20.8%) was the most frequent causative organism for in-hospital IE, followed by Staphylococcus aureus (16.7%) and enterococci (8.3%). Patients who developed in-hospital IE after TAVR had significantly higher rates of death (20.8% vs 4.1%, P<0.001), septic shock (16.7% vs 0.8%, P<0.001), cardiogenic shock (12.5% vs 3.4%, P=0.02), acute kidney injury requiring haemodialysis (16.7% vs 1.6%, P<0.001), bleeding requiring transfusion (29.2% vs 11.3%, P=0.01), myocardial infarction (12.5% vs 2.1%, P<0.001) and permanent pacemaker removal (4.2% vs 0.05%, P<0.001) compared with patients without IE. Independent predictors of in-hospital IE after TAVR include younger age [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.89-0.95], drug abuse (OR 48.9, 95% CI 6.9-347.3) and human immunodeficiency virus (HIV) infection (OR 7.8, 95% CI 1.4-44.4).

CONCLUSION

IE occurred in 0.3% of patients after TAVR during the same hospitalization, resulting in higher rates of adverse outcomes including mortality. Patients with younger age, a history of drug abuse or HIV infection are at greater risk of in-hospital IE following TAVR, and would benefit from vigilant preventive measures perioperatively.

Strain-Gradient Position Mapping of Semiconductor Quantum Dots

We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35  nm down to ±1  nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.

PLD1 regulates Xenopus convergent extension movements by mediating Frizzled7 endocytosis for Wnt/PCP signal activation

Phospholipase D (PLD) is involved in the regulation of receptor-associated signaling, cell movement, cell adhesion and endocytosis. However, its physiological role in vertebrate development remains poorly understood. In this study, we show that PLD1 is required for the convergent extension (CE) movements during Xenopus gastrulation by activating Wnt/PCP signaling. Xenopus PLD1 protein is specifically enriched in the dorsal region of Xenopus gastrula embryo and loss or gain-of-function of PLD1 induce defects in gastrulation and CE movements. These defective phenotypes are due to impaired regulation of Wnt/PCP signaling pathway. Biochemical and imaging analysis using Xenopus tissues reveal that PLD1 is required for Fz7 receptor endocytosis upon Wnt11 stimulation. Moreover, we show that Fz7 endocytosis depends on dynamin and regulation of GAP activity of dynamin by PLD1 via its PX domain is crucial for this process. Taken together, our results suggest that PLD1 acts as a new positive mediator of Wnt/PCP signaling by promoting Wnt11-induced Fz7 endocytosis for precise regulation of Xenopus CE movements.

Strain-mediated coupling in a quantum dot-mechanical oscillator hybrid system

Recent progress in nanotechnology has allowed the fabrication of new hybrid systems in which a single two-level system is coupled to a mechanical nanoresonator. In such systems the quantum nature of a macroscopic degree of freedom can be revealed and manipulated. This opens up appealing perspectives for quantum information technologies, and for the exploration of the quantum-classical boundary. Here we present the experimental realization of a monolithic solid-state hybrid system governed by material strain: a quantum dot is embedded within a nanowire that features discrete mechanical resonances corresponding to flexural vibration modes. Mechanical vibrations result in a time-varying strain field that modulates the quantum dot transition energy. This approach simultaneously offers a large light-extraction efficiency and a large exciton-phonon coupling strength g0. By means of optical and mechanical spectroscopy, we find that g0/2 π is nearly as large as the mechanical frequency, a criterion that defines the ultrastrong coupling regime.

Optimising the management of choroidal neovascularisation in Asian patients: consensus on treatment recommendations for anti-VEGF therapy

In Asian countries, age-related macular degeneration (AMD), specifically wet AMD or choroidal neovascularisation (CNV), is an important cause of blindness and visual handicap. Vascular endothelial growth factors (VEGF) play an integral role in the development of CNV and thus provide an important therapeutic target. Current treatment paradigms for neovascular AMD recognise the place of photodynamic therapy (PDT) in the management of this condition. However, combination therapy targeting different pathways to produce a synergistic effect may result in improved visual outcomes and reduced duration of treatment. Anti-VEGF therapy has greatly improved treatment outcomes in patients with CNV, and a growing body of evidence supports the role of these agents as monotherapy or in combination with PDT. In particular, anti-VEGF may be a first-line treatment option in certain types of subfoveal myopic CNV as well as for classic and occult juxtafoveal and subfoveal CNV. The implementation of evidence-based medicine into current clinical practice is paramount to improving patient care. The authors, who are also members of the Singapore Medical Retina Advisory Board, outline the consensus points and recommended treatment algorithms based on currently available knowledge to provide a structured management approach to the treatment of Asian patients with CNV.

Argon laser photocoagulation for the treatment of polypoidal choroidal vasculopathy

AIM

To evaluate the efficacy of conventional argon laser for the treatment of serosanguineous maculopathy secondary to polypoidal choroidal vasculopathy (PCV).

METHODS

A retrospective audit of patients who had argon laser photocoagulation to angiographically determined polypoidal lesions and subsequently followed up at 1, 3, 6, and 12 months post treatment.

RESULTS

Twenty-one eyes (75%) had stable or improved vision at 12 months. Twenty-three eyes had extrafoveal, two eyes had juxtafoveal, and three eyes had subfoveal polyps. In the extrafoveal group, 18 eyes (78%) had stable or improved vision at 12 months. Eighteen eyes (64.3%) showed clinical or angiographic resolution of maculopathy. Three eyes (10.7%) had recurrence of polyps subfoveally, three eyes (10.7%) had subsequent choroidal neovascularisation, and four eyes (14.3%) had persistent leakage with neurosensory detachment.

CONCLUSION

In our study, 18 of the 23 eyes which had extrafoveal polyps had stable or improved best-corrected visual acuity and showed complete resolution of maculopathy at 12 months follow-up. Argon laser photocoagulation would appear to be most beneficial for extrafoveal PCV. However, in view of the retrospective nature of this study, the true efficacy of argon laser treatment would have to be evaluated with a larger, prospective and randomised controlled trial.

Correlation between peripapillary atrophy and corticosteroid therapy in patients with Vogt-Koyanagi-Harada disease

AIMS

To determine the correlation between systemic corticosteroid therapy and the occurrence and size of peripapillary atrophy (PPA) in patients with Vogt-Koyanagi-Harada (VKH) disease.

METHODS

All patients with VKH disease were retrospectively reviewed for their corticosteroid regimen. The extent of the PPA, if present, was measured using digitized imaging software, by two masked observers. Eyes with myopia greater than 6 dioptres or glaucoma were excluded. The patients were classified into three groups: early high (EH), late high (LH), and low dose (LD), according to the dose and timing of corticosteroids received during the acute phase of the disease.

RESULTS

There were 40 eyes in the EH group, 25 eyes in the LH group, and 23 eyes in the LD group. Multivariate analysis showed that corticosteroid therapy was the main determinant of PPA occurrence. All the eyes in the LD group had PPA and eyes in the LH groups were 4.02 times (95% confidence interval 1.24-13.07) more likely to develop PPA than those in the EH group. The LD group also had larger PPA to disc ratios than the EH group. (Mean of 2.83 vs0.19, P<0.001).

CONCLUSION

The development and extent of PPA in patients with VKH disease appear to be dependent on the dose and timing of systemic corticosteroids.