Search

Background and objective: Decline in hospitalizations for various respiratory diseases has been reported during the COVID‐19 pandemic, but what led to such an observation is uncertain. Methods: This was a territory‐wide, retrospective cohort study involving all public hospital admissions in Hong Kong from 1 January 2017 to 31 December 2020. Hospital admissions for respiratory diseases, including asthma, COPD and non‐COVID pneumonia, were assessed. COVID‐related admissions were excluded from this study. The time of commencement of the pandemic was taken from the fourth week of January 2020. The associations between air pollutant levels, influenza and mask‐wearing rates with hospital admissions were assessed by mediation analyses. Results: There were altogether 19,485, 78,693 and 238,781 admissions for asthma, COPD and non‐COVID pneumonia from January 2017 to December 2020. There was a marked reduction in hospital admissions of asthma, COPD and non‐COVID pneumonia (37%, 36% and 12% decrease in average daily admissions, respectively) during the COVID‐19 pandemic compared to before. Air pollutant levels and influenza rate were decreased while mask‐wearing rate was increased. Collinearity of mask‐wearing rates and pandemic year was observed. For COPD, NO2, SO2, PM10 and influenza rates (4%, 11%, 4% and 4% of the total effect, respectively), while for non‐COVID pneumonia, PM10 and influenza rates (11% and 52%, respectively) had significant mediation effect on changes in hospital admissions before and during the COVID‐19 pandemic. Conclusion: During the COVID‐19 pandemic, a decrease in air pollutant levels and influenza rate had mediation effect on the reduction in hospitalizations of COPD and non‐COVID pneumonia. The reason behind the observation of decline in respiratory hospitalizations during the COVID‐19 pandemic was uncertain. This study found that air pollutants levels and influenza rate had mediation effects on the decrease in hospitalizations for COPD and non‐COVID pneumonia, but not for asthma during the COVID‐19 pandemic. See relatedEditorial [ABSTRACT FROM AUTHOR]

Abstract The identification of angiogenic growth factors, such as vascular endothelial growth factor and fibroblast growth factor, has fueled interest in using such factors to induce therapeutic angiogenesis. The results of numerous animal studies and clinical trials have offered promise for new treatment strategies for various ischemic diseases. Increased understanding of the cellular and molecular biology of vessel growth has, however, prompted investigators and clinicians alike to reconsider the complexity of therapeutic angiogenesis. The realization that formation of a stable vessel is a complex, multistep process may provide useful insights into the design of the next generation of angiogenesis therapy.

Fenestrae are small pores in the endothelium of renal glomerular, gastrointestinal, and endocrine gland capillaries and are involved in the bidirectional exchange of molecules between blood and tissues. Although decades of studies have characterized fenestrae at the ultrastructural level, little is known on the mechanisms by which fenestrae form. We present the development of an in vitro assay in which rapid and abundant fenestra induction enables a detailed study of their biogenesis. Through the use of agents that stabilize or disassemble actin microfilaments, we show that actin microfilament remodeling is part of fenestra biogenesis in this model. Furthermore, by using a loss-of-function approach, we show that the diaphragm protein PV-1 is necessary for fenestral pore architecture and the ordered arrangement of fenestrae in sieve plates. Together, these data provide insight into the cell biology of fenestra formation and open up the future study of the fenestra to a combined morphological and biochemical analysis. actin filaments | sieve plates | VEGF | vascular permeability

Aptamers recognize their targets with extraordinary affinity and specificity. The aptamer-based therapeutic, Macugen, is derived from a modified 2'fluoro pyrimidine RNA inhibitor to vascular endothelial growth factor (VEGF) and is now being used to treat the wet form of age-related macular degeneration. This VEGF16s aptamer binds specifically to the VEG[F.sub.165] isoform, a dimeric protein with a receptor-binding domain and a heparin-binding domain (HBD). To understand the molecular recognition between VEGF and this aptamer, binding experiments were used to show that the HBD contributes the majority of binding energy in the VEG[F.sub.165]-aptamer complex. A tissue culture-based competition assay demonstrated that the HBD effectively competes with VEG[F.sub.165] for aptamer binding in vivo. Comparison of NMR spectra revealed that structural features of the smaller HBD-aptamer complex are present in the full-length VEG[F.sub.164]-aptamer complex. These data show that the HBD provides the binding site for the aptamer and is the primary determinant for the affinity and specificity in the VEG[F.sub.165]-aptamer complex. age-related macular degeneration | Macugen | RNA | NMR

The authors review the publications on arteriogenesis. The topics of interest include the role of sensory nerves in arteriogenesis and the effect of the membrane-spanning Notch signaling system on paracrine regulation of vessel formation.

In the absence of vascular endothelial growth factor genes, VEGF(sub.164) and VEGF(sub.188), in mice, impaired myocardial angiogenesis is seen as are reduced myocardial perfusion and fatal ischemic cardiomyopathy. The pursuit of gene therapy strategies of ischemic heart disease led researchers to generate the mice using targeted embryonic stem cells.

This article in Advanced Synthesis & Catalysis discusses the palladium-catalyzed chemoselective amination of chloro(hetero)aryl triflates using alkyl-pyrazole-based phosphine ligands. The front cover picture features a sea hawk, or osprey, which symbolizes the accuracy of the reaction. The alkyl-pyrazolyl-phosphine ligand is highlighted as playing a crucial role in achieving selectivity and reactivity towards the C-Cl bond in the substrates. The article provides further details on this research, conducted by Chau Ming So and co-workers. [Extracted from the article]