Analysis of the correlation between BMI and respiratory tract microbiota in acute exacerbation of COPD.

Objective: To investigate the distribution differences in the respiratory tract microbiota of AECOPD patients in different BMI groups and explore its guiding value for treatment. Methods: Sputum samples of thirty-eight AECOPD patients were collected. The patients were divided into low, normal and high BMI group. The sputum microbiota was sequenced by 16S rRNA detection technology, and the distribution of sputum microbiota was compared. Rarefaction curve, α-diversity, principal coordinate analysis (PCoA) and measurement of sputum microbiota abundance in each group were performed and analyzed by bioinformatics methods. Results: 1. The rarefaction curve in each BMI group reached a plateau. No significant differences were observed in the OTU total number or α-diversity index of microbiota in each group. PCoA showed significant differences in the distance matrix of sputum microbiota between the three groups, which was calculated by the Binary Jaccard and the Bray Curtis algorithm. 2. At the phylum level, most of the microbiota were Proteobacteria, Bacteroidetes Firmicutes, Actinobacteria, and Fusobacteria. At the genus level, most were Streptococcus, Prevotella, Haemophilus, Neisseria and Bacteroides. 3. At the phylum level, the abundance of Proteobacteria in the low group was significantly higher than that in normal and high BMI groups, the abundances of Firmicutes in the low and normal groups were significantly lower than that in high BMI groups. At the genus level, the abundance of Haemophilus in the low group was significantly higher than that in high BMI group, and the abundances of Streptococcus in the low and normal BMI groups were significantly lower than that in the high BMI group. Conclusions: 1. The sputum microbiota of AECOPD patients in different BMI groups covered almost all microbiota, and BMI had no significant association with total number of respiratory tract microbiota or α-diversity in AECOPD patients. However, there was a significant difference in the PCoA between different BMI groups. 2. The microbiota structure of AECOPD patients differed in different BMI groups. Gram-negative bacteria (G-) in the respiratory tract of patients predominated in the low BMI group, while gram-positive bacteria (G+) predominated in the high BMI group.

Engineering tunable terahertz radiation from an electron bunch using graphene metasurfaces.

We propose an approach to generate tunable terahertz (THz) radiation from an electron bunch passing over the unique graphene metasurface. We not only control the frequency of the THz radiation but also tune the amplitude and direction of the radiation by varying the chemical potential of the graphene. Several new phenomena are observed. The radiation has the same frequency with the resonant frequency of the graphene metasurface at normal incidence. The radiation frequency meets the linear relationship with the chemical potential. The radiation magnitude is the inverse to the reflection magnitude, and the sum of them is close to being a constant. The strong Smith-Purcell radiation on the graphene metasurface is due to the interaction between the electron bunch and periodic surface plasmon polaritons (SPPs). The stronger the SPP, the higher is the radiation magnitude that is obtained. These results would provide a promising way for developing tunable radiation in the THz band.

One-year follow-up study after patients with severe COVID-19 received human umbilical cord mesenchymal stem cells treatment.

BACKGROUND: The novel coronavirus is still mutating, and the pandemic continues. Meanwhile, many COVID-19 survivors have residual postinfection clinical manifestations. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been shown to be effective in the early stages of COVID-19. OBJECTIVES: The aim of this study was to investigate long-term safety and efficacy of treatment in patients with severe COVID-19 patients who had received hUC-MSCs therapy. METHODS: Twenty-five discharged patients who had severe COVID-19 (including the standard treatment group and the standard treatment plus hUC-MSCs group) were enrolled in a 1-year follow-up. The assessment considered adverse effects (including effects on liver and kidney function, coagulation, ECG, tumor marker, and so on), pulmonary function, St George's Respiratory Questionnaire (SGRQ), postinfection sequelae and serum concentration of Krebs von den Lungen-6 (KL-6), malondialdehyde (MDA), H2S, carnitine, and N-6 long-chain polyunsaturated fatty acids (N-6 LC-PUFAs). MEASUREMENTS AND MAIN RESULTS: Pulmonary ventilation function had significantly improved at the 1-year follow-up in both the hUC-MSCs group and the control group compared with the 3-month follow-up (P < 0.01). Fatigue (60% [15/25]) remained the most common symptom at the 1-year follow-up. The rate of fatigue relief was significantly reduced in the hUC-MSCs group (25% [2/8]) compared to the control group (76.5% [13/17]) (P = 0.028). The level of KL-6 was significantly lower in the hUC-MSCs group (2585.5 ± 186.5 U/ml) than in the control group (3120.7 ± 158.3 U/ml) (P < 0.001). Compared with the control group, the hUC-MSCs group had a lower level of MDA (9.27 ± 0.54 vs. 9.91 ± 0.72 nmol/ml, P = 0.036). No obvious adverse effects were observed in the hUC-MSCs treatment group at 1 year after discharge. CONCLUSIONS: Intravenous transplantation of hUC-MSCs was a safe approach in the long term in the treatment of patients with severe COVID-19. In addition, hUC-MSCs had a positive effect on postinfection sequelae in COVID-19 survivors. TRIAL REGISTRATION: Chinese Clinical Trial Registration; ChiCTR2000031494; Registered 02 April 2020-Retrospectively registered, http://www.medresman.org.

Human Umbilical Cord Mesenchymal Stromal Cell Treatment of Severe COVID-19 Patients: A 3-Month Follow-Up Study Following Hospital Discharge.

Previously, we demonstrated the therapeutic effects of human umbilical cord mesenchymal stromal cells (hUC-MSCs) in severe coronavirus disease 2019 (COVID-19) patients. In this 3-month follow-up study, we examined discharged patients who had received hUC-MSC therapy to assess the safety of this therapy and the health-related quality of life (HRQL) of these patients. The follow-up cohort consisted of 28 discharged severe COVID-19 patients who received either the standard treatment (the control group) or the standard treatment plus hUC-MSC therapy. We examined liver function, kidney function, pulmonary function, coagulation, tumor markers, and vision. We also conducted electrocardiography (ECG) analysis, let the patients answer the St. George's Respiratory Questionnaire (SGRQ), and performed computed tomography (CT) imaging for assessing the lung changes. No obvious adverse effects were observed in the hUC-MSC group after 3 months. Measurements of blood routine index, C-reactive protein and procalcitonin, liver and kidney function, coagulation, ECG, tumor markers, and vision were almost within the normal ranges in both the treatment and control groups. Forced expiratory volumes in 1 s (FEV1) (% of predicted) were 71.88% ± 8.46% and 59.45% ± 27.45% in the hUC-MSC and control groups (P < 0.01), respectively, and FEV1/forced vital capacity (FEV1/FVC) ratios were 79.95% ± 8.00% and 58.97% ± 19.16% in the hUC-MSC and control groups, respectively (P < 0.05). SGRQ scores were lower in the hUC-MSC group than in the control group (15.25 ± 3.69 vs. 31.9 ± 8.78, P < 0.05). The rate of wheezing in the hUC-MSC group was also significantly lower than that in the control group (37.5% vs. 75%, P < 0.05). There were no significant differences in CT scores between the two groups (0.60 ± 0.88 vs. 1.00 ± 1.31, P = 0.917). Overall, the intravenous transplantation of hUC-MSCs accelerated partial pulmonary function recovery and improved HRQL, indicating relative safety and preliminary efficacy of this treatment for patients with severe COVID-19.

Clinical characteristics of moderate COVID-19 patients aggravation in Wuhan Stadium Cabin Hospital: A 571 cases of retrospective cohort study.

To report the clinical characteristics and potential risk factors of patients with coronavirus disease 2019 (COVID-19) in Wuhan Stadium Cabin Hospital in Hubei Province. A total of 571 patients of COVID-19 treated in the Wuhan Stadium Cabin Hospital were selected for analysis, univariable and multivariable logistic regression methods were used to explore the risk factors associated with disease aggravation. The main clinical symptoms of moderate COVID-19 were fever, cough and dyspnea, hypertension, diabetes, and coronary heart diseases were the main comorbidities both in transferred and stable patients. Twenty-six patients (4.55%) of mild and moderate patients had disease aggravation, and most of which occurred between 36 and 48 hours after admission. Multiple regression analysis showed increasing odds of disease aggravation associated with former smoker history, diabetes, dyspnea, consolidation, and interstitial abnormalities of computed tomography scanning, lymphopenia and elevated of C-reactive protein, the time points of transferred patients mainly between 36 and 48 hours (65.38%), and the average hospital stay for stable patients was 15 days.It could help clinicians to identify patients with poor prognosis at an early stage, and provide early warning role for timely intervention.

Treatment of severe COVID-19 with human umbilical cord mesenchymal stem cells.

BACKGROUND: COVID-19 is a highly infectious respiratory disease. No therapeutics have yet been proven effective for treating severe COVID-19. OBJECTIVES: To determine whether human umbilical cord mesenchymal stem cell infusion may be effective and safe for the treatment of severe COVID-19. METHODS: Patients with severe COVID-19 were randomly divided into 2 groups: the standard treatment group and the standard treatment plus hUC-MSC infusion group. The incidence of progression from severe to critical illness, 28-day mortality, clinical symptom improvement, time to clinical symptom improvement, hematologic indicators including C-reactive protein, lymphocyte number, and interleukin 6, and imaging changes were observed and compared between the two groups. MEASUREMENTS AND MAIN RESULTS: The incidence of progression from severe to critical illness and the 28-day mortality rate were 0 in the hUC-MSC treatment group, while 4 patients in the control group deteriorated to critical condition and received invasive ventilation; 3 of them died, and the 28-day mortality rate was 10.34%. In the hUC-MSC treatment group, the time to clinical improvement was shorter than that in the control group. Clinical symptoms of weakness and fatigue, shortness of breath, and low oxygen saturation obviously improved beginning on the third day of stem cell infusion and reached a significant difference on day 7. CRP and IL-6 levels were significantly lower from day 3 of infusion, the time for the lymphocyte count to return to the normal range was significantly faster, and lung inflammation absorption was significantly shorter on CT imaging in the hUC-MSC group than in the control group. CONCLUSIONS: Intravenous transplantation of hUC-MSCs is a safe and effective method that can be considered a salvage and priority treatment option for severe COVID-19. TRIAL REGISTRATION: Chinese Clinical Trial Registration; ChiCTR2000031494; Registered on 2 April 2020; http:// www.medresman.org.

Glycol Chitosan Engineered Autoregenerative Antioxidant Significantly Attenuates Pathological Damages in Models of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the foremost cause of irreversible blindness in people over the age of 65 especially in developing countries. Therefore, an exploration of effective and alternative therapeutic interventions is an unmet medical need. It has been established that oxidative stress plays a key role in the pathogenesis of AMD, and hence, neutralizing oxidative stress is an effective therapeutic strategy for treatment of this serious disorder. Owing to autoregenerative properties, nanoceria has been widely used as a nonenzymatic antioxidant in the treatment of oxidative stress related disorders. Yet, its potential clinical implementation has been greatly hampered by its poor water solubility and lack of reliable tracking methodologies/processes and hence poor absorption, distribution, and targeted delivery. The water solubility and surface engineering of a drug with biocompatible motifs are fundamental to pharmaceutical products and precision medicine. Here, we report an engineered water-soluble, biocompatible, trackable nanoceria with enriched antioxidant activity to scavenge intracellular reactive oxygen species (ROS). Experimental studies with in vitro and in vivo models demonstrated that this antioxidant is autoregenerative and more active in inhibiting laser-induced choroidal neovascularization by decreasing ROS-induced pro-angiogenic vascular endothelial growth factor (VEGF) expression, cumulative oxidative damage, and recruitment of endothelial precursor cells without exhibiting any toxicity. This advanced formulation may offer a superior therapeutic effect to deal with oxidative stress induced pathogeneses, such as AMD.

Cell surface- and rho GTPase-based auxin signaling controls cellular interdigitation in Arabidopsis.

Auxin is a multifunctional hormone essential for plant development and pattern formation. A nuclear auxin-signaling system controlling auxin-induced gene expression is well established, but cytoplasmic auxin signaling, as in its coordination of cell polarization, is unexplored. We found a cytoplasmic auxin-signaling mechanism that modulates the interdigitated growth of Arabidopsis leaf epidermal pavement cells (PCs), which develop interdigitated lobes and indentations to form a puzzle-piece shape in a two-dimensional plane. PC interdigitation is compromised in leaves deficient in either auxin biosynthesis or its export mediated by PINFORMED 1 localized at the lobe tip. Auxin coordinately activates two Rho GTPases, ROP2 and ROP6, which promote the formation of complementary lobes and indentations, respectively. Activation of these ROPs by auxin occurs within 30 s and depends on AUXIN-BINDING PROTEIN 1. These findings reveal Rho GTPase-based auxin-signaling mechanisms, which modulate the spatial coordination of cell expansion across a field of cells.

Two seven-transmembrane domain MILDEW RESISTANCE LOCUS O proteins cofunction in Arabidopsis root thigmomorphogenesis.

Directional root expansion is governed by nutrient gradients, positive gravitropism and hydrotropism, negative phototropism and thigmotropism, as well as endogenous oscillations in the growth trajectory (circumnutation). Null mutations in phylogenetically related Arabidopsis thaliana genes MILDEW RESISTANCE LOCUS O 4 (MLO4) and MLO11, encoding heptahelical, plasma membrane-localized proteins predominantly expressed in the root tip, result in aberrant root thigmomorphogenesis. mlo4 and mlo11 mutant plants show anisotropic, chiral root expansion manifesting as tightly curled root patterns upon contact with solid surfaces. The defect in mlo4 and mlo11 mutants is nonadditive and dependent on light and nutrients. Genetic epistasis experiments demonstrate that the mutant phenotype is independently modulated by the Gbeta subunit of the heterotrimeric G-protein complex. Analysis of expressed chimeric MLO4/MLO2 proteins revealed that the C-terminal domain of MLO4 is necessary but not sufficient for MLO4 action in root thigmomorphogenesis. The expression of the auxin efflux carrier fusion, PIN1-green fluorescent protein, the pattern of auxin-induced gene expression, and acropetal as well as basipetal auxin transport are altered at the root tip of mlo4 mutant seedlings. Moreover, addition of auxin transport inhibitors or the loss of EIR1/AGR1/PIN2 function abolishes root curling of mlo4, mlo11, and wild-type seedlings. These results demonstrate that the exaggerated root curling phenotypes of the mlo4 and mlo11 mutants depend on auxin gradients and suggest that MLO4 and MLO11 cofunction as modulators of touch-induced root tropism.

Genetic and biochemical characterization of Drosophila Snipper: A promiscuous member of the metazoan 3'hExo/ERI-1 family of 3' to 5' exonucleases.

The DnaQ-H family exonuclease Snipper (Snp) is a 33-kDa Drosophila melanogaster homolog of 3'hExo and ERI-1, exoribonucleases implicated in the degradation of histone mRNA in mammals and in the negative regulation of RNA interference (RNAi) in Caenorhabditis elegans, respectively. In metazoans, Snp, Exod1, 3'hExo, ERI-1, and the prpip nucleases define a new subclass of structure-specific 3'-5' exonucleases that bind and degrade double-stranded RNA and/or DNA substrates with 3' overhangs of 2-5 nucleotides (nt) in the presence of Mg2+ with no apparent sequence specificity. These nucleases are also capable of degrading linear substrates. Snp efficiently degrades structured RNA and DNA substrates as long as there exists a minimum 3' overhang of 2 nt to initiate degradation. We identified a Snp mutant and used it to test whether Snp plays a role in regulating histone mRNA degradation or RNAi in vivo. Snp mutant flies are viable, and display no obvious developmental abnormalities. The expression pattern and level of histone H3 mRNA in Snp mutant embryos and third instar imaginal eye discs was indistinguishable from wild type, suggesting that Snp does not play a significant role in the turnover of histone mRNA at the end of the S phase. The loss of Snp was also unable to enhance the silencing capability of two different RNAi transgenes targeting the white and yellow genes, suggesting that Snp does not negatively modulate RNAi. Therefore, Snp is a nonessential exonuclease that is not a functional ortholog of either 3'hExo or ERI-1.

Expression analysis of the AtMLO gene family encoding plant-specific seven-transmembrane domain proteins.

The Arabidopsis (Arabidopsis thaliana) genome contains 15 genes encoding protein homologs of the barley mildew resistance locus o (MLO) protein biochemically shown to have a seven-transmembrane domain topology and localize to the plasma membrane. Towards elucidating the functions of MLOs, the largest family of seven-transmembrane domain proteins specific to plants, we comprehensively determined AtMLO gene expression patterns by a combination of experimental and in silico studies. Experimentation comprised analyses of transgenic Arabidopsis lines bearing promoter::Beta-glucuronidase (GUS) transcriptional fusions as well as semi-quantitative determination of transcripts by reverse transcription coupled to polymerase chain reaction (RT-PCR). These results were combined with information extracted from public gene profiling databases, and compared to the expression patterns of genes encoding the heterotrimeric G-protein subunits. We found that each AtMLO gene has a unique expression pattern and is regulated differently by a variety of biotic and/or abiotic stimuli, suggesting that AtMLO proteins function in diverse developmental and response processes. The expression of several phylogenetically closely-related AtMLO genes showed similar or overlapping tissue specificity and analogous responsiveness to external stimuli, suggesting functional redundancy, co-function, or antagonistic function(s).