Dynamics of Oxygen-Independent Photocleavage of Blebbistatin as a One-Photon Blue or Two-Photon Near-Infrared Light-Gated Hydroxyl Radical Photocage

Development of versatile, chemically tunable photocages for photoactivated chemotherapy (PACT) represents an excellent opportunity to address the technical drawbacks of conventional photodynamic therapy (PDT) whose oxygen-dependent nature renders it inadequate in certain therapy contexts such as hypoxic tumors. As an alternative to PDT, oxygen free mechanisms to generate cytotoxic reactive oxygen species (ROS) by visible light cleavable photocages are in demand. Here, we report the detailed mechanisms by which the small molecule blebbistatin acts as a one-photon blue light-gated or two-photon near-infrared light-gated photocage to directly release a hydroxyl radical (•OH) in the absence of oxygen. By using femtosecond transient absorption spectroscopy and chemoselective ROS fluorescent probes, we analyze the dynamics and fate of blebbistatin during photolysis under blue light. Water-dependent photochemistry reveals a critical process of water-assisted protonation and excited state intramolecular proton transfer (ESIPT) that drives the formation of short-lived intermediates, which surprisingly culminates in the release of •OH but not superoxide or singlet oxygen from blebbistatin. CASPT2//CASSCF calculations confirm that hydrogen bonding between water and blebbistatin underpins this process. We further determine that blue light enables blebbistatin to induce mitochondria-dependent apoptosis, an attribute conducive to PACT development. Our work demonstrates blebbistatin as a controllable photocage for •OH generation and provides insight into the potential development of novel PACT agents

Image_2_Vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children: A longitudinal cohort study.JPEG

ObjectiveTo investigate the picture between vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children.MethodsA retrospective, longitudinal cohort study was performed. All included hospitalized cases were divided into the sufficient (sVD) and insufficient vitamin D (iVD) groups according to whether their serum 25-hydroxyvitamin D [25(OH)D] concentration was ≥30 ng/mL. Dynamic changes in clinical parameters were observed for seven time periods within 28 days after admission.ResultsSerum 25(OH)D concentrations were significantly negatively correlated with age in the included cases (r = −0.6; P ConclusionsChildren with vitamin D insufficiency might have poorer clinical outcomes in Omicron subvariant BA.2 infection, especially in older pediatric patients. Further studies are needed to assess effectiveness of supplements in reducing the same.</p

Table_1_Vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children: A longitudinal cohort study.pdf

ObjectiveTo investigate the picture between vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children.MethodsA retrospective, longitudinal cohort study was performed. All included hospitalized cases were divided into the sufficient (sVD) and insufficient vitamin D (iVD) groups according to whether their serum 25-hydroxyvitamin D [25(OH)D] concentration was ≥30 ng/mL. Dynamic changes in clinical parameters were observed for seven time periods within 28 days after admission.ResultsSerum 25(OH)D concentrations were significantly negatively correlated with age in the included cases (r = −0.6; P ConclusionsChildren with vitamin D insufficiency might have poorer clinical outcomes in Omicron subvariant BA.2 infection, especially in older pediatric patients. Further studies are needed to assess effectiveness of supplements in reducing the same.</p

Image_1_Vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children: A longitudinal cohort study.JPEG

ObjectiveTo investigate the picture between vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children.MethodsA retrospective, longitudinal cohort study was performed. All included hospitalized cases were divided into the sufficient (sVD) and insufficient vitamin D (iVD) groups according to whether their serum 25-hydroxyvitamin D [25(OH)D] concentration was ≥30 ng/mL. Dynamic changes in clinical parameters were observed for seven time periods within 28 days after admission.ResultsSerum 25(OH)D concentrations were significantly negatively correlated with age in the included cases (r = −0.6; P ConclusionsChildren with vitamin D insufficiency might have poorer clinical outcomes in Omicron subvariant BA.2 infection, especially in older pediatric patients. Further studies are needed to assess effectiveness of supplements in reducing the same.</p

Table_2_Vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children: A longitudinal cohort study.DOCX

ObjectiveTo investigate the picture between vitamin D levels and clinical outcomes of SARS-CoV-2 Omicron subvariant BA.2 in children.MethodsA retrospective, longitudinal cohort study was performed. All included hospitalized cases were divided into the sufficient (sVD) and insufficient vitamin D (iVD) groups according to whether their serum 25-hydroxyvitamin D [25(OH)D] concentration was ≥30 ng/mL. Dynamic changes in clinical parameters were observed for seven time periods within 28 days after admission.ResultsSerum 25(OH)D concentrations were significantly negatively correlated with age in the included cases (r = −0.6; P ConclusionsChildren with vitamin D insufficiency might have poorer clinical outcomes in Omicron subvariant BA.2 infection, especially in older pediatric patients. Further studies are needed to assess effectiveness of supplements in reducing the same.</p

Image_1_The Relationship Between Hepcidin-Mediated Iron Dysmetabolism and COVID-19 Severity: A Meta-Analysis.JPEG

BackgroundsHepcidin has been identified as a systemic iron-regulatory hormone. Recent studies have suggested that iron metabolism disorders may be involved in the pathogenesis of acute respiratory distress syndrome and multiple organ dysfunction in coronavirus disease 2019 (COVID-19).ObjectivesTo re-evaluate the hepcidin-related iron metabolism parameters and explore the relationship between hepcidin-mediated iron dysmetabolism and COVID-19 severity.MethodsCOVID-19 is classified as mild and moderate as non-severe, severe and critical as severe. A meta-analysis was conducted. Four bibliographic databases were comprehensively searched up to December 31st 2021.ResultsSix unique studies with data from 477 COVID-19 patients were included. Compared to non-severe cases, severe cases had higher hepcidin (standardized mean difference (SMD), −0.39; 95% Confidence Interval (CI) [−0.76, −0.03]; P = 0.03) and ferritin (SMD, −0.84; 95% CI [−1.30, −0.38]; P = 0.0004). In five out of six studies, a total of 427 patients were tested for serum iron, and there were significant differences in their levels between severe and non-severe cases (SMD, 0.22; 95% CI [0.02, 0.41]; P = 0.03). A total of 320 patients from four out of six studies were tested for transferrin saturation, and the statistical difference was not significant (SMD, 0.06; 95% CI [−0.17, 0.28]; P = 0.64).ConclusionSevere COVID-19 cases had higher serum levels of hepcidin and ferritin, and lower serum iron, without significant differences in transferrin saturation. Further studies are needed to verify whether targeting the hepcidin-mediated iron metabolism axis may influence the outcome and treatment of COVID-19.</p

Transition of <i>bla</i>_OXA-58-like to <i>bla</i>_OXA-23-like in <i>Acinetobacter baumannii</i> Clinical Isolates in Southern China: An 8-Year Study

<div><p>Background</p><p>The prevalence of carbapenem-resistant <i>Acinetobacter baumannii</i> in hospitals has been increasing worldwide. This study aims to investigate the carbapenemase genes and the clonal relatedness among <i>A</i>. <i>baumannii</i> clinical isolates in a Chinese hospital.</p><p>Methods</p><p>Carbapenemase genes and the upstream locations of insertion sequences were detected by polymerase chain reaction (PCR), and the clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing.</p><p>Results</p><p>A total of 231 nonduplicate carbapenemase gene-harboring <i>A</i>. <i>baumannii</i> clinical isolates recovered from Shenzhen People’s Hospital, were investigated between 2002 and 2009. <i>bla</i>_OXA-23-like, <i>bla</i>_OXA-58-like, <i>bla</i>_OXA-40-like, and IS<i>Aba1</i>-<i>bla</i>_OXA-51-like were identified in 119, 107, 1, and 4 isolates, respectively. IS<i>1008</i>-ΔIS<i>Aba3</i>, IS<i>Aba3</i>, and IS<i>Aba1</i> were detected upstream of the <i>bla</i>_OXA-58-like gene in 69, 35, and 3 isolates, respectively. All <i>bla</i>_OXA-23-like genes but one had an upstream insertion of IS<i>Aba1</i>. <i>bla</i>_OXA-58-like was the most common carbapenemase gene in <i>A</i>.<i>baumannii</i> before 2008, thereafter <i>bla</i>_OXA-23-like became rapidly prevalent and replaced <i>bla</i>_OXA-58-like in 2009. The majority of <i>bla</i>_OXA-58-like-carrying isolates showed lower level of resistance to imipenem and meropenem (minimum inhibitory concentrations (MICs), 1 μg/ml to 16 μg/ml), compared with the majority of <i>bla</i>_OXA-23-like-carrying isolates (MICs, 16 μg/ml to 64 μg/ml for both imipenem and meropenem). All 231 <i>bla</i>_OXA carbapenemase gene-harboring isolates belonged to 14 PFGE types (A–N), and three dominant clones A, J, and H accounted for 43.3%, 42.0%, and 8.2% of the tested isolates, respectively. Clone A (sequence type ST92/ST208) with <i>bla</i>_OXA-58-like was the most prevalent before 2008. Clone H (ST229) with <i>bla</i>_OXA-23-like became striking between 2007 and 2008. Clone J (ST381) with <i>bla</i>_OXA-23-like rapidly spread and replaced clones A and H in 2009.</p><p>Conclusion</p><p>This study is the first to reveal that the distinct <i>bla</i>_OXA-23-like-carrying <i>A</i>. <i>baumannii</i> ST381 displaced the previously prevalent <i>bla</i>_OXA-58-like-carrying <i>A</i>. <i>baumannii</i> ST92/ST208, resulting in the rapidly increasing resistance to carbapenems in <i>A</i>. <i>baumannii</i> in Shenzhen People’s Hospital in 2009.</p></div

PFGE dendrogram of 10 representative isolates from the three dominant clones.

<p>Allelic profile: seven loci in the order <i>gltA</i>, <i>gyrB</i>, <i>gdhB</i>, <i>recA</i>, <i>cpn60</i>, <i>gpi</i>, and <i>rpoD</i>; MIC μg/ml; IPM, imipenem; MEM, meropenem.</p

<i>A</i>. <i>baumannii</i> (Ab) isolates with imipenem and/or meropenem MICs ≥ 0.25 μg/ml from 2002 to 2009.

<p>^<i>a</i> Parentheses refer to the number of patients</p><p><i>A</i>. <i>baumannii</i> (Ab) isolates with imipenem and/or meropenem MICs ≥ 0.25 μg/ml from 2002 to 2009.</p

Antibiotic resistance profiles of the three main carbapenemase gene-harboring <i>A</i>. <i>baumannii</i> clones (MIC μg/ml).

<p>IPM, imipenem; MEM, meropenem; CSL, cefoperazone-sulbactam; SAM, ampicillin-sulbactam; FEP, cefepime; TZP, piperacillin-tazobactam; CAZ, ceftazidime; CRO, ceftriaxone; AMK, amikacin; CIP, ciprofloxacin; LEV, levofloxacin; SXT, trimethoprim-sulfamethoxazole; POL, polymixin B; MNO, minocycline; TGC, tigecycline</p><p>R, resistant; S, susceptible</p><p>^<i>a</i> CLSI (2007) breakpoint for cefoperazone was used for cefoperazone-sulbactam in this study.</p><p>^<i>b</i> U.S. FDA criteria for tigecycline were used in this study (susceptibility is defined as ≤ 2μg/ml; resistance as ≥ 8 μg/ml).</p><p>Antibiotic resistance profiles of the three main carbapenemase gene-harboring <i>A</i>. <i>baumannii</i> clones (MIC μg/ml).</p