ORCID Profile
0000-0002-1401-7861
Current Organisations
University of California, San Diego
,
The University of Auckland
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 02-2018
Publisher: American Society for Microbiology
Date: 29-10-2010
Abstract: The initiation of hyperinvasive disease in group A Streptococcus (GAS) serotype M1T1 occurs by mutation within the covRS two-component regulon (named covRS for c ontrol o f v irulence r egulatory s ensor kinase), which promotes resistance to neutrophil-mediated killing through the upregulation of bacteriophage-encoded Sda1 DNase. To determine whether other virulence factors contribute to this phase-switching phenomenon, we studied a panel of 10 isogenic GAS serotype M1T1 virulence gene knockout mutants. While loss of several in idual virulence factors did not prevent GAS covRS switching in vivo , we found that M1 protein and hyaluronic acid capsule are indispensable for the switching phenotype, a phenomenon previously attributed uniquely to the Sda1 DNase. We demonstrate that like M1 protein and Sda1, capsule expression enhances survival of GAS serotype M1T1 within neutrophil extracellular traps. Furthermore, capsule shares with M1 protein a role in GAS resistance to human cathelicidin antimicrobial peptide LL-37. We conclude that a quorum of GAS serotype M1T1 virulence genes with cooperative roles in resistance to neutrophil extracellular killing is essential for the switch to a hyperinvasive phenotype in vivo . IMPORTANCE The pathogen group A Streptococcus (GAS) causes a wide range of human infections ranging from the superficial “strep throat” to potentially life-threatening conditions, such as necrotizing fasciitis, also known as “flesh-eating disease.” A marked increase in the number of cases of severe invasive GAS infection during the last 30 years has been traced to the emergence and spread of a single clone of the M1T1 serotype. Recent studies have shown that GAS serotype M1T1 bacteria undergo a genetic “switch” in vivo to a hypervirulent state that allows dissemination into the bloodstream. The present study was undertaken to identify specific GAS serotype M1T1 virulence factors required for this switch to hypervirulence. The surface-anchored GAS M1 protein and hyaluronic acid capsule are found to be essential for the switching phenotype, and a novel role for capsule in GAS resistance to host defense peptides and neutrophil extracellular killing is revealed.
Publisher: Ubiquity Press, Ltd.
Date: 29-09-2016
DOI: 10.5334/UJIEL.321
Publisher: Elsevier BV
Date: 2010
DOI: 10.1016/J.AHJ.2009.10.034
Abstract: Major bleeding significantly impacts outcomes in patients undergoing percutaneous coronary intervention (PCI). No uniform definitions exist for major and minor bleeding. Hematomas > or =5 cm at the femoral puncture site are considered major bleeding events in some trials and minor in others. Limited information is available on the incidence and clinical relevance of hematomas > or =5 cm in PCI patients. Data from the STEEPLE trial in patients undergoing elective PCI were used to assess the impact of hematomas > or =5 cm on ischemic outcomes (mortality, nonfatal myocardial infarction, or urgent target vessel revascularization) up to day 30 and all-cause 1-year mortality. Hematoma data were available for 3,342 of 3,528 patients in STEEPLE. Patients with (n = 103) and without (n = 3,239) hematomas > or =5 cm were evenly distributed across treatment groups. No differences were observed in 30-day ischemic outcomes between patients with and without hematomas (5.8% vs 5.9%, respectively P = .96). No transfusions were observed in patients with hematomas as compared with patients without hematomas (0% and 0.4%, respectively P = .52). A greater reduction in hemoglobin was observed (pre- vs post-PCI) in patients with hematomas as compared with patients without hematomas (-0.84 vs -0.35 g/L, P or =5 cm had no effect on 30-day ischemic events or 1-year mortality. Although there is no agreed classification for large hematomas, the lack of a relationship between hematomas > or =5 cm and clinical outcome after PCI justifies the classification of these hematomas as minor bleeds in STEEPLE.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.IJCARD.2008.10.008
Abstract: Obese patients are at increased risk of acute coronary syndromes (ACS). We evaluated the prevalence of obesity in a large ACS population, as well as the relationship between body mass index (BMI) and the use of cardiac medications and procedures, clinical outcomes, and treatment effects between enoxaparin and unfractionated heparin (UFH). Using the database of the SYNERGY trial, we identified 9978 patients in 12 countries who were randomly assigned to receive enoxaparin or UFH. Patient weight at baseline and 30-day follow-up was recorded. BMI information was available on 9837 patients. BMI was analyzed in clinically meaningful categories ( or =35 kg/m(2)) and as a continuous variable. Thirty-two percent of patients were obese (BMI> or =30), with a greater proportion of patients with obesity from North America (36%) compared with other regions. Enoxaparin was dosed as 1 mg/kg regardless of body weight without maximum. The first dose of enoxaparin was underdosed in 15% of patients assigned enoxaparin, and obese patients were more likely to be underdosed than non-obese patients. Obese patients were younger, less often white, had more diabetes, hypertension, hyperlipidemia, family history of coronary artery disease, and congestive heart failure but fewer strokes, less peripheral vascular disease, and less often smoked. After adjustment, increased BMI was not an independent predictor of bleeding outcomes or 30-day death/myocardial infarction (MI), but increased BMI was predictive of lower 1-year mortality in the subgroup of patients with BMI at baseline below approximately 30 kg/m(2). No statistical interaction term was observed between obesity and randomized therapy for the outcomes of death/MI at 30 days and 6 months death at 30 days, 6 months, and 1 year and GUSTO or TIMI bleeding. Nearly one third of patients in SYNERGY were obese. Despite multiple comorbidities, obese patients had better unadjusted short- and long-term outcomes. After adjustment, higher BMI was not an independent predictor of in-hospital bleeding events or 30-day death/MI, but increased BMI was an independent predictor of 1-year mortality in patients with lower BMI but not in heavier patients. No interaction between the randomized treatment and obesity for efficacy and safety outcomes was observed across the range of BMI in this dataset. Standard dosing of enoxaparin should be used in patients without extreme obesity due to limited outcome data in these patients.
Publisher: American Association for Cancer Research (AACR)
Date: 15-12-2012
DOI: 10.1158/0008-5472.CAN-12-2359
Abstract: Cathelicidins are a family of bacteriocidal polypeptides secreted by macrophages and polymorphonuclear leukocytes (PMN). LL-37, the only human cathelicidin, has been implicated in tumorigenesis, but there has been limited investigation of its expression and function in cancer. Here, we report that LL-37 activates a p53-mediated, caspase-independent apoptotic cascade that contributes to suppression of colon cancer. LL-37 was expressed strongly in normal colon mucosa but downregulated in colon cancer tissues, where in both settings its expression correlated with terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling-positive apoptotic cells. Exposure of colon cancer cells to LL-37 induced phosphatidylserine externalization and DNA fragmentation in a manner independent of caspase activation. Apoptogenic function was mediated by nuclear translocation of the proapoptotic factors, apoptosis-inducing factor (AIF) and endonuclease G (EndoG), through p53-dependent upregulation of Bax and Bak and downregulation of Bcl-2 via a pertussis toxin–sensitive G-protein–coupled receptor (GPCR) pathway. Correspondingly, colonic mucosa of cathelicidin-deficient mice exhibited reduced expression of p53, Bax, and Bak and increased expression of Bcl-2 together with a lower basal level of apoptosis. Cathelicidin-deficient mice exhibited an increased susceptibility to azoxymethane-induced colon tumorigenesis, establishing pathophysiologic relevance in colon cancer. Collectively, our findings show that LL-37 activates a GPCR-p53-Bax/Bak/Bcl-2 signaling cascade that triggers AIF/EndoG–mediated apoptosis in colon cancer cells. Cancer Res 72(24) 6512–23. ©2012 AACR.
Publisher: Springer Science and Business Media LLC
Date: 30-03-2022
Publisher: eLife Sciences Publications, Ltd
Date: 19-10-2021
DOI: 10.7554/ELIFE.66793
Abstract: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important emerging zoonotic pathogen that causes severe skin infections. To combat infections from drug-resistant bacteria, the transplantation of commensal antimicrobial bacteria as a therapeutic has shown clinical promise. We screened a collection of erse staphylococcus species from domestic dogs and cats for antimicrobial activity against MRSP. A unique strain ( S. felis C4) was isolated from feline skin that inhibited MRSP and multiple gram-positive pathogens. Whole genome sequencing and mass spectrometry revealed several secreted antimicrobials including a thiopeptide bacteriocin micrococcin P1 and phenol-soluble modulin beta (PSMβ) peptides that exhibited antimicrobial and anti-inflammatory activity. Fluorescence and electron microscopy revealed that S. felis antimicrobials inhibited translation and disrupted bacterial but not eukaryotic cell membranes. Competition experiments in mice showed that S. felis significantly reduced MRSP skin colonization and an antimicrobial extract from S. felis significantly reduced necrotic skin injury from MRSP infection. These findings indicate a feline commensal bacterium that could be utilized in bacteriotherapy against difficult-to-treat animal and human skin infections.
Publisher: Elsevier BV
Date: 11-2009
DOI: 10.1016/J.JCIN.2009.08.016
Abstract: Our purpose was to evaluate long-term mortality and identify factors associated with 1-year mortality in patients who underwent elective percutaneous coronary intervention (PCI). While long-term outcomes in PCI patients have been reported previously, limited data are currently available regarding the comparative long-term outcomes in PCI patients who receive enoxaparin versus intravenous unfractionated heparin (UFH). We conducted a follow-up analysis of clinical outcomes at 1 year in patients enrolled in the STEEPLE (SafeTy and Efficacy of Enoxaparin in Percutaneous coronary intervention patients, an internationaL randomized Evaluation) trial of 3,528 patients undergoing elective PCI. Patients were randomized to receive either intravenous 0.50-mg/kg or 0.75-mg/kg enoxaparin or intravenous UFH during elective PCI procedures. All-cause mortality at 1 year after index PCI was the main outcome measure. Mortality rates were 1.4%, 2.0%, and 1.5% from 1 month to 1 year, and 2.3%, 2.2%, and 1.9% from randomization to 1 year, after index PCI in patients receiving 0.50 mg/kg enoxaparin, 0.75 mg/kg enoxaparin, and UFH, respectively. Multivariate analysis identified nonfatal myocardial infarction and/or urgent target vessel revascularization up to 30 days after index PCI (hazard ratio: 3.5, 95% confidence interval: 1.7 to 7.3 p < 0.001), and major bleeding within 48 h (hazard ratio: 3.0, 95% confidence interval: 1.1 to 8.5 p = 0.04) as the strongest independent risk factors for 1-year mortality. The 1-year mortality rates were low and comparable between patients receiving enoxaparin and UFH during elective PCI. Periprocedural ischemic or bleeding events were the strongest independent predictors of 1-year mortality. (The STEEPLE Trial NCT00077844).
Publisher: eLife Sciences Publications, Ltd
Date: 20-09-2021
Publisher: Wiley
Date: 27-02-2022
DOI: 10.1111/JELS.12310
Abstract: Copyright termination laws in the United States allow creators to end their copyright assignments and licences after various time periods and regain their rights. These laws are designed to protect authors and their heirs by giving them a second opportunity to profit from their works, where they might have assigned them initially for relatively little. Similar laws are in force and being recommended for implementation around the world. However, there is little data on how these laws are being used. Such data is vital because it provides insights into the pros and cons of different systems. We fill this gap by providing the first large‐scale study of copyright termination notice records from the U.S. Copyright Office. Utilising data scraping and manipulation techniques in the Python programming language, we have created two brand new datasets for scholars, copyright experts, creators, publishers, and other industry stakeholders to examine. In our accompanying paper, we document some preliminary trends from the data and how it might be used for further analysis.
Publisher: Edward Elgar Publishing
Date: 15-06-2023
Publisher: Informa UK Limited
Date: 06-2007
DOI: 10.1128/MCB.00379-07
Publisher: Springer Science and Business Media LLC
Date: 20-12-2012
DOI: 10.1038/GT.2012.92
Abstract: Cathelicidin, an antimicrobial peptide of the innate immune system, has been shown to modulate microbial growth, wound healing and inflammation. However, whether cathelicidin controls Helicobacter pylori infection in vivo remains unexplored. This study sought to elucidate the role of endogenous and exogenous mouse cathelicidin (CRAMP) in the protection against H. pylori infection and the associated gastritis in mice. Results showed that genetic ablation of CRAMP in mice significantly increased the susceptibility of H. pylori colonization and the associated gastritis as compared with the wild-type control. Furthermore, replenishment with exogenous CRAMP, delivered via a bioengineered CRAMP-secreting strain of Lactococcus lactis, reduced H. pylori density in the stomach as well as the associated inflammatory cell infiltration and cytokine production. Collectively, these findings indicate that cathelicidin protects against H. pylori infection and its associated gastritis in vivo. Our study also demonstrates the feasibility of using the transformed food-grade bacteria to deliver cathelicidin, which may have potential clinical applications in the treatment of H. pylori infection in humans.
Publisher: The American Association of Immunologists
Date: 15-02-2016
Abstract: The antimicrobial peptide cathelicidin is critical for protection against different kinds of microbial infection. This study sought to elucidate the protective action of cathelicidin against Helicobacter pylori infection and its associated gastritis. Exogenous cathelicidin was found to inhibit H. pylori growth, destroy the bacteria biofilm, and induce morphological alterations in H. pylori membrane. Additionally, knockdown of endogenous cathelicidin in human gastric epithelial HFE-145 cells markedly increased the intracellular survival of H. pylori. Consistently, cathelicidin knockout mice exhibited stronger H. pylori colonization, higher expression of proinflammatory cytokines IL-6, IL-1β, and ICAM1, and lower expression of the anti-inflammatory cytokine IL-10 in the gastric mucosa upon H. pylori infection. In wild-type mice, H. pylori infection also stimulated gastric epithelium-derived cathelicidin production. Importantly, pretreatment with bioengineered Lactococcus lactis that actively secretes cathelicidin significantly increased mucosal cathelicidin levels and reduced H. pylori infection and the associated inflammation. Moreover, cathelicidin strengthened the barrier function of gastric mucosa by stimulating mucus synthesis. Collectively, these findings indicate that cathelicidin plays a significant role as a potential natural antibiotic for H. pylori clearance and a therapeutic agent for chronic gastritis.
Publisher: Elsevier BV
Date: 11-2012
Publisher: Springer Science and Business Media LLC
Date: 03-2012
DOI: 10.1038/GT.2012.22
Abstract: Cathelicidin is a pleiotropic host defense peptide secreted by epithelial and immune cells. Whether endogenous cathelicidin is protective against ulcerative colitis, however, is unclear. Here we sought to delineate the role of endogenous murine cathelicidin (mCRAMP) and the therapeutic efficacy of intrarectal administration of mCRAMP-encoding plasmid in ulcerative colitis using dextran sulfate sodium (DSS)-challenged cathelicidin-knockout (Cnlp(-/-)) mice as a model. Cnlp(-/-) mice had more severe symptoms and mucosal disruption than the wild-type mice in response to DSS challenge. The tissue levels of interleukin-1β and tumor necrosis factor-α, myeloperoxidase activity and the number of apoptotic cells were increased in the colon of DSS-challenged Cnlp(-/-) mice. Moreover, mucus secretion and mucin gene expression were impaired in Cnlp(-/-) mice. All these abnormalities were reversed by the intrarectal administration of mCRAMP or mCRAMP-encoding plasmid. Taken together, endogenous cathelicidin may protect against ulcerative colitis through modulation of inflammation and mucus secretion.
Publisher: Oxford University Press (OUP)
Date: 02-06-2023
Location: United States of America
No related grants have been discovered for Richard Gallo.