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1.
Cell ; 167(2): 301, 2016 Oct 06.
Article in English | MEDLINE | ID: mdl-27716499

ABSTRACT

Avycaz combines an older cephalosporin antibiotic, ceftazidime, and the ß-lactamase inhibitor avibactam. Ceftazidime targets penicillin-binding proteins (PBPs) in the bacterial periplasm that are required for cell wall synthesis. Avibactam blocks ß-lactamases (ß-L) in the periplasm, which would otherwise inactivate the antibiotics resulting in drug resistance.


Subject(s)
Anti-Bacterial Agents , Azabicyclo Compounds , Bacteria/drug effects , Ceftazidime , Penicillin-Binding Proteins/antagonists & inhibitors , beta-Lactamase Inhibitors , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Azabicyclo Compounds/chemistry , Azabicyclo Compounds/pharmacology , Azabicyclo Compounds/therapeutic use , Ceftazidime/chemistry , Ceftazidime/pharmacology , Ceftazidime/therapeutic use , Cell Wall/drug effects , Drug Combinations , Drug Resistance, Bacterial , Humans , Urinary Tract Infections/drug therapy , beta-Lactamase Inhibitors/chemistry , beta-Lactamase Inhibitors/pharmacology , beta-Lactamase Inhibitors/therapeutic use
2.
Mol Cell ; 82(17): 3151-3165.e9, 2022 09 01.
Article in English | MEDLINE | ID: mdl-35907401

ABSTRACT

Rifamycin antibiotics such as rifampin are potent inhibitors of prokaryotic RNA polymerase (RNAP) used to treat tuberculosis and other bacterial infections. Although resistance arises in the clinic principally through mutations in RNAP, many bacteria possess highly specific enzyme-mediated resistance mechanisms that modify and inactivate rifamycins. The expression of these enzymes is controlled by a 19-bp cis-acting rifamycin-associated element (RAE). Guided by the presence of RAE sequences, we identify a helicase-like protein, HelR, in Streptomyces venezuelae that confers broad-spectrum rifamycin resistance. We show that HelR also promotes tolerance to rifamycins, enabling bacterial evasion of the toxic properties of these antibiotics. HelR forms a complex with RNAP and rescues transcription inhibition by displacing rifamycins from RNAP, thereby providing resistance by target protection . Furthermore, HelRs are broadly distributed in Actinobacteria, including several opportunistic Mycobacterial pathogens, offering yet another challenge for developing new rifamycin antibiotics.


Subject(s)
Rifamycins , Tuberculosis , Anti-Bacterial Agents/pharmacology , DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Humans , Rifampin/metabolism , Rifampin/pharmacology , Rifamycins/pharmacology , Streptomyces/enzymology
3.
Nat Chem Biol ; 20(2): 234-242, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37973888

ABSTRACT

The efficacy of aminoglycoside antibiotics is waning due to the acquisition of diverse resistance mechanisms by bacteria. Among the most prevalent are aminoglycoside acetyltransferases (AACs) that inactivate the antibiotics through acetyl coenzyme A-mediated modification. Most AACs are members of the GCN5 superfamily of acyltransferases which lack conserved active site residues that participate in catalysis. ApmA is the first reported AAC belonging to the left-handed ß-helix superfamily. These enzymes are characterized by an essential active site histidine that acts as an active site base. Here we show that ApmA confers broad-spectrum aminoglycoside resistance with a molecular mechanism that diverges from other detoxifying left-handed ß-helix superfamily enzymes and canonical GCN5 AACs. We find that the active site histidine plays different functions depending on the acetyl-accepting aminoglycoside substrate. This flexibility in the mechanism of a single enzyme underscores the plasticity of antibiotic resistance elements to co-opt protein catalysts in the evolution of drug detoxification.


Subject(s)
Aminoglycosides , Histidine , Aminoglycosides/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Acetyltransferases/genetics , Acetyltransferases/metabolism , Bacteria/metabolism
4.
Nature ; 578(7796): 582-587, 2020 02.
Article in English | MEDLINE | ID: mdl-32051588

ABSTRACT

Addressing the ongoing antibiotic crisis requires the discovery of compounds with novel mechanisms of action that are capable of treating drug-resistant infections1. Many antibiotics are sourced from specialized metabolites produced by bacteria, particularly those of the Actinomycetes family2. Although actinomycete extracts have traditionally been screened using activity-based platforms, this approach has become unfavourable owing to the frequent rediscovery of known compounds. Genome sequencing of actinomycetes reveals an untapped reservoir of biosynthetic gene clusters, but prioritization is required to predict which gene clusters may yield promising new chemical matter2. Here we make use of the phylogeny of biosynthetic genes along with the lack of known resistance determinants to predict divergent members of the glycopeptide family of antibiotics that are likely to possess new biological activities. Using these predictions, we uncovered two members of a new functional class of glycopeptide antibiotics-the known glycopeptide antibiotic complestatin and a newly discovered compound we call corbomycin-that have a novel mode of action. We show that by binding to peptidoglycan, complestatin and corbomycin block the action of autolysins-essential peptidoglycan hydrolases that are required for remodelling of the cell wall during growth. Corbomycin and complestatin have low levels of resistance development and are effective in reducing bacterial burden in a mouse model of skin MRSA infection.


Subject(s)
Anti-Bacterial Agents , Drug Discovery , Peptides, Cyclic , Peptidoglycan/drug effects , Peptidoglycan/metabolism , Actinobacteria/chemistry , Actinobacteria/genetics , Actinobacteria/metabolism , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Biosynthetic Pathways/genetics , Cell Wall/metabolism , Chlorophenols/chemistry , Chlorophenols/metabolism , Chlorophenols/pharmacology , Disease Models, Animal , Drug Resistance, Microbial/drug effects , Drug Resistance, Microbial/genetics , Female , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice , Microbial Sensitivity Tests , Multigene Family , N-Acetylmuramoyl-L-alanine Amidase/antagonists & inhibitors , Peptides, Cyclic/chemistry , Peptides, Cyclic/metabolism , Peptides, Cyclic/pharmacology , Phylogeny , Skin/microbiology , Staphylococcal Infections/microbiology
5.
Proc Natl Acad Sci U S A ; 120(16): e2221253120, 2023 04 18.
Article in English | MEDLINE | ID: mdl-37043535

ABSTRACT

The outer membrane of gram-negative bacteria prevents many antibiotics from reaching intracellular targets. However, some antimicrobials can take advantage of iron import transporters to cross this barrier. We showed previously that the thiopeptide antibiotic thiocillin exploits the nocardamine xenosiderophore transporter, FoxA, of the opportunistic pathogen Pseudomonas aeruginosa for uptake. Here, we show that FoxA also transports the xenosiderophore bisucaberin and describe at 2.5 Å resolution the crystal structure of bisucaberin bound to FoxA. Bisucaberin is distinct from other siderophores because it forms a 3:2 rather than 1:1 siderophore-iron complex. Mutations in a single extracellular loop of FoxA differentially affected nocardamine, thiocillin, and bisucaberin binding, uptake, and signal transduction. These results show that in addition to modulating ligand binding, the extracellular loops of siderophore transporters are of fundamental importance for controlling ligand uptake and its regulatory consequences, which have implications for the development of siderophore-antibiotic conjugates to treat difficult infections.


Subject(s)
Anti-Bacterial Agents , Siderophores , Siderophores/metabolism , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/metabolism , Ligands , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , Iron/metabolism , Signal Transduction , Pseudomonas aeruginosa/genetics , Bacterial Outer Membrane Proteins/metabolism , Bacterial Proteins/metabolism
6.
Genome Res ; 32(4): 778-790, 2022 04.
Article in English | MEDLINE | ID: mdl-35210353

ABSTRACT

More than 90% of genetic variants are rare in most modern sequencing studies, such as the Alzheimer's Disease Sequencing Project (ADSP) whole-exome sequencing (WES) data. Furthermore, 54% of the rare variants in ADSP WES are singletons. However, both single variant and unit-based tests are limited in their statistical power to detect an association between rare variants and phenotypes. To best use missense rare variants and investigate their biological effect, we examine their association with phenotypes in the context of protein structures. We developed a protein structure-based approach, protein optimized kernel evaluation of missense nucleotides (POKEMON), which evaluates rare missense variants based on their spatial distribution within a protein rather than their allele frequency. The hypothesis behind this test is that the three-dimensional spatial distribution of variants within a protein structure provides functional context to power an association test. POKEMON identified three candidate genes (TREM2, SORL1, and EXOC3L4) and another suggestive gene from the ADSP WES data. For TREM2 and SORL1, two known Alzheimer's disease (AD) genes, the signal from the spatial cluster is stable even if we exclude known AD risk variants, indicating the presence of additional low-frequency risk variants within these genes. EXOC3L4 is a novel AD risk gene that has a cluster of variants primarily shared by case subjects around the Sec6 domain. This cluster is also validated in an independent replication data set and a validation data set with a larger sample size.


Subject(s)
Alzheimer Disease , Alzheimer Disease/genetics , Gene Frequency , Genetic Predisposition to Disease , Humans , LDL-Receptor Related Proteins/genetics , LDL-Receptor Related Proteins/metabolism , Membrane Transport Proteins/genetics , Mutation, Missense , Phenotype , Exome Sequencing
7.
Ann Neurol ; 95(4): 625-634, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38180638

ABSTRACT

Alzheimer's disease (AD) is the most common neurodegenerative disorder and one of the leading causes of disability worldwide. The apolipoprotein E4 gene (APOE4) is the strongest genetic risk factor for AD. In 2023, the APOE4 National Institute on Aging/Alzheimer's Disease Sequencing Project working group came together to gather data and discuss the question of whether to reduce or increase APOE4 as a therapeutic intervention for AD. It was the unanimous consensus that cumulative data from multiple studies in humans and animal models support that lowering APOE4 should be a target for therapeutic approaches for APOE4 carriers. ANN NEUROL 2024;95:625-634.


Subject(s)
Alzheimer Disease , Animals , United States , Humans , Alzheimer Disease/therapy , Alzheimer Disease/drug therapy , Apolipoprotein E4/genetics , Goals , National Institute on Aging (U.S.)
8.
PLoS Genet ; 18(7): e1009977, 2022 07.
Article in English | MEDLINE | ID: mdl-35788729

ABSTRACT

African descent populations have a lower Alzheimer disease risk from ApoE ε4 compared to other populations. Ancestry analysis showed that the difference in risk between African and European populations lies in the ancestral genomic background surrounding the ApoE locus (local ancestry). Identifying the mechanism(s) of this protection could lead to greater insight into the etiology of Alzheimer disease and more personalized therapeutic intervention. Our objective is to follow up the local ancestry finding and identify the genetic variants that drive this risk difference and result in a lower risk for developing Alzheimer disease in African ancestry populations. We performed association analyses using a logistic regression model with the ApoE ε4 allele as an interaction term and adjusted for genome-wide ancestry, age, and sex. Discovery analysis included imputed SNP data of 1,850 Alzheimer disease and 4,331 cognitively intact African American individuals. We performed replication analyses on 63 whole genome sequenced Alzheimer disease and 648 cognitively intact Ibadan individuals. Additionally, we reproduced results using whole-genome sequencing of 273 Alzheimer disease and 275 cognitively intact admixed Puerto Rican individuals. A further comparison was done with SNP imputation from an additional 8,463 Alzheimer disease and 11,365 cognitively intact non-Hispanic White individuals. We identified a significant interaction between the ApoE ε4 allele and the SNP rs10423769_A allele, (ß = -0.54,SE = 0.12,p-value = 7.50x10-6) in the discovery data set, and replicated this finding in Ibadan (ß = -1.32,SE = 0.52,p-value = 1.15x10-2) and Puerto Rican (ß = -1.27,SE = 0.64,p-value = 4.91x10-2) individuals. The non-Hispanic Whites analyses showed an interaction trending in the "protective" direction but failing to pass a 0.05 significance threshold (ß = -1.51,SE = 0.84,p-value = 7.26x10-2). The presence of the rs10423769_A allele reduces the odds ratio for Alzheimer disease risk from 7.2 for ApoE ε4/ε4 carriers lacking the A allele to 2.1 for ApoE ε4/ε4 carriers with at least one A allele. This locus is located approximately 2 mB upstream of the ApoE locus, in a large cluster of pregnancy specific beta-1 glycoproteins on chromosome 19 and lies within a long noncoding RNA, ENSG00000282943. This study identified a new African-ancestry specific locus that reduces the risk effect of ApoE ε4 for developing Alzheimer disease. The mechanism of the interaction with ApoEε4 is not known but suggests a novel mechanism for reducing the risk for ε4 carriers opening the possibility for potential ancestry-specific therapeutic intervention.


Subject(s)
Alzheimer Disease , Alleles , Alzheimer Disease/genetics , Apolipoprotein E4/genetics , Apolipoproteins E/genetics , Genotype , Humans , Nigeria , Risk Factors
9.
J Infect Dis ; 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38298144

ABSTRACT

BACKGROUND: Macrolide antibiotics, including azithromycin, can reduce under-five mortality rates and treat various infections in children in sub-Saharan Africa. These exposures, however, can select for antibiotic-resistant bacteria in the gut microbiota. METHODS: Our previous randomized controlled trial (RCT) of a rapid-test-and-treat strategy for severe acute diarrhoeal disease in children in Botswana included an intervention (three-day azithromycin dose) group and a control group that received supportive treatment. In this prospective matched cohort study using stools collected at baseline and 60 days after treatment from RCT participants, the collection of antibiotic resistance genes or resistome was compared between groups. RESULTS: Certain macrolide resistance genes increased in prevalence by 13% to 55% at 60 days, without differences in gene presence between the intervention and control groups. These genes were linked to tetracycline resistance genes and mobile genetic elements. CONCLUSIONS: Azithromycin treatment for bacterial diarrhoea for young children in Botswana resulted in similar effects on the gut resistome as the supportive treatment and did not provide additional selective pressure for macrolide resistance gene maintenance. The gut microbiota of these children contains diverse macrolide resistance genes that may be transferred within the gut upon repeated exposures to azithromycin or co-selected by other antibiotics.

10.
Acta Neuropathol ; 147(1): 55, 2024 03 12.
Article in English | MEDLINE | ID: mdl-38472475

ABSTRACT

Inclusions comprised of microtubule-associated protein tau (tau) are implicated in a group of neurodegenerative diseases, collectively known as tauopathies, that include Alzheimer's disease (AD). The spreading of misfolded tau "seeds" along neuronal networks is thought to play a crucial role in the progression of tau pathology. Consequently, restricting the release or uptake of tau seeds may inhibit the spread of tau pathology and potentially halt the advancement of the disease. Previous studies have demonstrated that the Mammalian Suppressor of Tauopathy 2 (MSUT2), an RNA binding protein, modulates tau pathogenesis in a transgenic mouse model. In this study, we investigated the impact of MSUT2 on tau pathogenesis using tau seeding models. Our findings indicate that the loss of MSUT2 mitigates human tau seed-induced pathology in neuron cultures and mouse models. In addition, MSUT2 regulates many gene transcripts, including the Adenosine Receptor 1 (A1AR), and we show that down regulation or inhibition of A1AR modulates the activity of the "ArfGAP with SH3 Domain, Ankyrin Repeat, and PH Domain 1 protein" (ASAP1), thereby influencing the internalization of pathogenic tau seeds into neurons resulting in reduction of tau pathology.


Subject(s)
Alzheimer Disease , Tauopathies , Mice , Humans , Animals , Brain/pathology , tau Proteins/metabolism , Tauopathies/pathology , Alzheimer Disease/pathology , Neurons/pathology , Mice, Transgenic , Mammals/metabolism , Adaptor Proteins, Signal Transducing/metabolism
11.
Pediatr Blood Cancer ; : e31143, 2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38924670

ABSTRACT

ChatGPT and other artificial intelligence (AI) systems have captivated the attention of healthcare providers and researchers for their potential to improve care processes and outcomes. While these technologies hold promise to automate processes, increase efficiency, and reduce cognitive burden, their use also carries risks. In this commentary, we review basic concepts of AI, outline some of the capabilities and limitations of currently available tools, discuss current and future applications in pediatric hematology/oncology, and provide an evaluation and implementation framework that can be used by pediatric hematologist/oncologists considering the use of AI in clinical practice.

12.
Nanotechnology ; 35(36)2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38537254

ABSTRACT

We investigate the photon statistics of the light emitted by single self-assembled hybrid gold-CdSe/CdS/CdZnS colloidal nanocrystal supraparticles through the detailed analysis of the intensity autocorrelation functiong(2)(τ). We first reveal that, despite the large number of nanocrystals involved in the supraparticle emission, antibunching can be observed. We then present a model based on non-coherent Förster energy transfer and Auger recombination that well captures photon antibunching. Finally, we demonstrate that some supraparticles exhibit a bunching effect at short time scales corresponding to coherent collective emission.

13.
Proc Natl Acad Sci U S A ; 118(44)2021 11 02.
Article in English | MEDLINE | ID: mdl-34716264

ABSTRACT

Bacterial cell wall peptidoglycan is essential, maintaining both cellular integrity and morphology, in the face of internal turgor pressure. Peptidoglycan synthesis is important, as it is targeted by cell wall antibiotics, including methicillin and vancomycin. Here, we have used the major human pathogen Staphylococcus aureus to elucidate both the cell wall dynamic processes essential for growth (life) and the bactericidal effects of cell wall antibiotics (death) based on the principle of coordinated peptidoglycan synthesis and hydrolysis. The death of S. aureus due to depletion of the essential, two-component and positive regulatory system for peptidoglycan hydrolase activity (WalKR) is prevented by addition of otherwise bactericidal cell wall antibiotics, resulting in stasis. In contrast, cell wall antibiotics kill via the activity of peptidoglycan hydrolases in the absence of concomitant synthesis. Both methicillin and vancomycin treatment lead to the appearance of perforating holes throughout the cell wall due to peptidoglycan hydrolases. Methicillin alone also results in plasmolysis and misshapen septa with the involvement of the major peptidoglycan hydrolase Atl, a process that is inhibited by vancomycin. The bactericidal effect of vancomycin involves the peptidoglycan hydrolase SagB. In the presence of cell wall antibiotics, the inhibition of peptidoglycan hydrolase activity using the inhibitor complestatin results in reduced killing, while, conversely, the deregulation of hydrolase activity via loss of wall teichoic acids increases the death rate. For S. aureus, the independent regulation of cell wall synthesis and hydrolysis can lead to cell growth, death, or stasis, with implications for the development of new control regimes for this important pathogen.


Subject(s)
Cell Wall/physiology , Peptidoglycan/metabolism , Staphylococcus aureus/growth & development , Anti-Bacterial Agents/pharmacology , Anti-Infective Agents/metabolism , Anti-Infective Agents/pharmacology , Bacterial Proteins/metabolism , Cell Wall/metabolism , Homeostasis , Methicillin/pharmacology , N-Acetylmuramoyl-L-alanine Amidase/metabolism , Staphylococcal Infections/microbiology , Staphylococcus aureus/metabolism , Teichoic Acids/metabolism , Vancomycin/pharmacology
14.
Alzheimers Dement ; 20(1): 253-265, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37578203

ABSTRACT

INTRODUCTION: Multiple infectious agents, including viruses, bacteria, fungi, and protozoa, have been linked to Alzheimer's disease (AD) risk by independent lines of evidence. We explored this association by comparing the frequencies of viral species identified in a large sample of AD cases and controls. METHODS: DNA sequence reads that did not align to the human genome in sequences were mapped to viral reference sequences, quantified, and then were tested for association with AD in whole exome sequences (WES) and whole genome sequences (WGS) datasets. RESULTS: Several viruses were significant predictors of AD according to the machine learning classifiers. Subsequent regression analyses showed that herpes simplex type 1 (HSV-1) (odds ratio [OR] = 3.71, p = 8.03 × 10-4) and human papillomavirus 71 (HPV-71; OR = 3.56, p = 0.02), were significantly associated with AD after Bonferroni correction. The phylogenetic-related cluster of Herpesviridae was significantly associated with AD in several strata of the data (p < 0.01). DISCUSSION: Our results support the hypothesis that viral infection, especially HSV-1, is associated with AD risk.


Subject(s)
Alzheimer Disease , Herpes Simplex , Herpesvirus 1, Human , Humans , Alzheimer Disease/complications , Phylogeny , Herpesvirus 1, Human/genetics , DNA
15.
Alzheimers Dement ; 20(2): 1250-1267, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37984853

ABSTRACT

BACKGROUND: Women demonstrate a memory advantage when cognitively healthy yet lose this advantage to men in Alzheimer's disease. However, the genetic underpinnings of this sex difference in memory performance remain unclear. METHODS: We conducted the largest sex-aware genetic study on late-life memory to date (Nmales  = 11,942; Nfemales  = 15,641). Leveraging harmonized memory composite scores from four cohorts of cognitive aging and AD, we performed sex-stratified and sex-interaction genome-wide association studies in 24,216 non-Hispanic White and 3367 non-Hispanic Black participants. RESULTS: We identified three sex-specific loci (rs67099044-CBLN2, rs719070-SCHIP1/IQCJ-SCHIP), including an X-chromosome locus (rs5935633-EGL6/TCEANC/OFD1), that associated with memory. Additionally, we identified heparan sulfate signaling as a sex-specific pathway and found sex-specific genetic correlations between memory and cardiovascular, immune, and education traits. DISCUSSION: This study showed memory is highly and comparably heritable across sexes, as well as highlighted novel sex-specific genes, pathways, and genetic correlations that related to late-life memory. HIGHLIGHTS: Demonstrated the heritable component of late-life memory is similar across sexes. Identified two genetic loci with a sex-interaction with baseline memory. Identified an X-chromosome locus associated with memory decline in females. Highlighted sex-specific candidate genes and pathways associated with memory. Revealed sex-specific shared genetic architecture between memory and complex traits.


Subject(s)
Alzheimer Disease , Cognitive Aging , Humans , Male , Female , Genome-Wide Association Study , Alzheimer Disease/genetics , Cognition , Sex Characteristics
16.
Alzheimers Dement ; 20(2): 1268-1283, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37985223

ABSTRACT

INTRODUCTION: Although large-scale genome-wide association studies (GWAS) have been conducted on AD, few have been conducted on continuous measures of memory performance and memory decline. METHODS: We conducted a cross-ancestry GWAS on memory performance (in 27,633 participants) and memory decline (in 22,365 participants; 129,201 observations) by leveraging harmonized cognitive data from four aging cohorts. RESULTS: We found high heritability for two ancestry backgrounds. Further, we found a novel ancestry locus for memory decline on chromosome 4 (rs6848524) and three loci in the non-Hispanic Black ancestry group for memory performance on chromosomes 2 (rs111471504), 7 (rs4142249), and 15 (rs74381744). In our gene-level analysis, we found novel genes for memory decline on chromosomes 1 (SLC25A44), 11 (BSX), and 15 (DPP8). Memory performance and memory decline shared genetic architecture with AD-related traits, neuropsychiatric traits, and autoimmune traits. DISCUSSION: We discovered several novel loci, genes, and genetic correlations associated with late-life memory performance and decline. HIGHLIGHTS: Late-life memory has high heritability that is similar across ancestries. We discovered four novel variants associated with late-life memory. We identified four novel genes associated with late-life memory. Late-life memory shares genetic architecture with psychiatric/autoimmune traits.


Subject(s)
Alzheimer Disease , Humans , Alzheimer Disease/genetics , Genome-Wide Association Study , Endophenotypes , Genetic Predisposition to Disease/genetics , Cognition , Memory Disorders/genetics , Polymorphism, Single Nucleotide/genetics
17.
Alzheimers Dement ; 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38958117

ABSTRACT

INTRODUCTION: Despite a two-fold risk, individuals of African ancestry have been underrepresented in Alzheimer's disease (AD) genomics efforts. METHODS: Genome-wide association studies (GWAS) of 2,903 AD cases and 6,265 controls of African ancestry. Within-dataset results were meta-analyzed, followed by functional genomics analyses. RESULTS: A novel AD-risk locus was identified in MPDZ on chromosome (chr) 9p23 (rs141610415, MAF = 0.002, P = 3.68×10-9). Two additional novel common and nine rare loci were identified with suggestive associations (P < 9×10-7). Comparison of association and linkage disequilibrium (LD) patterns between datasets with higher and lower degrees of African ancestry showed differential association patterns at chr12q23.2 (ASCL1), suggesting that this association is modulated by regional origin of local African ancestry. DISCUSSION: These analyses identified novel AD-associated loci in individuals of African ancestry and suggest that degree of African ancestry modulates some associations. Increased sample sets covering as much African genetic diversity as possible will be critical to identify additional loci and deconvolute local genetic ancestry effects. HIGHLIGHTS: Genetic ancestry significantly impacts risk of Alzheimer's Disease (AD). Although individuals of African ancestry are twice as likely to develop AD, they are vastly underrepresented in AD genomics studies. The Alzheimer's Disease Genetics Consortium has previously identified 16 common and rare genetic loci associated with AD in African American individuals. The current analyses significantly expand this effort by increasing the sample size and extending ancestral diversity by including populations from continental Africa. Single variant meta-analysis identified a novel genome-wide significant AD-risk locus in individuals of African ancestry at the MPDZ gene, and 11 additional novel loci with suggestive genome-wide significance at P < 9×10-7. Comparison of African American datasets with samples of higher degree of African ancestry demonstrated differing patterns of association and linkage disequilibrium at one of these loci, suggesting that degree and/or geographic origin of African ancestry modulates the effect at this locus. These findings illustrate the importance of increasing number and ancestral diversity of African ancestry samples in AD genomics studies to fully disentangle the genetic architecture underlying AD, and yield more effective ancestry-informed genetic screening tools and therapeutic interventions.

18.
Opt Express ; 31(3): 4454-4464, 2023 Jan 30.
Article in English | MEDLINE | ID: mdl-36785413

ABSTRACT

We report on the synthesis of hybrid light emitting particles with a diameter ranging between 100 and 500 nm, consisting in a compact semiconductor CdSe/CdS/CdZnS nanocrystal aggregate encapsulated by a controlled nanometric size silica and gold layers. We first characterize the Purcell decay rate enhancement corresponding to the addition of the gold nanoshell as a function of the particle size and find a good agreement with the predictions of numerical simulations. Then, we show that the contribution corresponding to Förster resonance energy transfer is inhibited.

19.
J Sex Med ; 20(7): 1025-1031, 2023 06 28.
Article in English | MEDLINE | ID: mdl-37158448

ABSTRACT

BACKGROUND: The organisms causing penile implant infections are changing from predominantly indolent gram-positive infections to more aggressive gram-negative and fungal infections because of antibiotic selection pressures based on novel next-generation sequencing DNA data. AIM: To evaluate the effectiveness of Irrisept solution (0.05% chlorhexidine gluconate) in decreasing isolate colony counts from a Titan implant by using a novel kill time washout methodology to mirror real-world usage. METHODS: Sterilized Titan discs were dipped in Irrisept or saline. An inoculum of 109 organisms of a single bacterial or fungal species was placed on the discs. Bacterial and fungal strains were tested: Bacteroides fragilis, Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. The discs were then irrigated 3 times with Irrisept or saline. Microorganisms were sonicated off the discs and placed on appropriate agar and conditions for each species. The plates were incubated for 48 to 72 hours at the temperature and under the conditions appropriate for each species. Colonies on the plates were hand counted. OUTCOMES: Irrisept effectively decreased microbial colony counts in all the species tested. RESULTS: Irrisept was shown to effectively decrease microbial colony counts from 3 to 6 log10 in all species tested. A 3-log10 reduction is considered the target level of performance that would indicate that a compound or product has effective killing activity against an organism of interest. The saline control with bulb syringe irrigation did not demonstrate reduction of microbial colony counts in any of the species tested. CLINICAL IMPLICATIONS: Irrisept is effective against all of the organisms causing modern-day infections with penile implant surgery and may decrease clinical infection rates to lower levels. STRENGTHS AND LIMITATIONS: The strength of this study is that we used quantitative microbial reduction counting and the largest array of bacterial and fungal species causing modern-day penile implant infections. The limitation is that this is an in vitro study and the clinical implications of our findings are not yet known. CONCLUSION: Quantitative microbial reduction counting shows that Irrisept is effective against the most commonly known modern-day organisms causing penile implant infections.


Subject(s)
Chlorhexidine , Penile Prosthesis , Humans , Anaerobiosis , Anti-Bacterial Agents/therapeutic use
20.
J Surg Oncol ; 127(4): 699-705, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36394434

ABSTRACT

BACKGROUND AND OBJECTIVES: We aim to assess the quality and readability of online information available to patients considering cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). METHODS: The top three search engines (Google, Bing, and Yahoo) were searched in March 2022. Websites were classified as academic, hospital-affiliated, foundation/advocacy, commercial, or unspecified. Quality of information was assessed using the JAMA benchmark criteria (0-4) and DISCERN tool (16-80), and the presence of a Health On the Net code (HONcode) seal. Readability was evaluated using the Flesch Reading Ease score. RESULTS: Fifty unique websites were included. The average JAMA and DISCERN scores of all websites were 0.72 ± 1.14 and 39.58 ± 13.71, respectively. Foundation/advocacy websites had significantly higher JAMA mean score than commercial (p = 0.044), academic (p < 0.001), and hospital-affiliated websites (p = 0.001). Foundation/advocacy sites had a significantly higher DISCERN mean score than hospital-affiliated (p = 0.035) and academic websites (p = 0.030). The HONcode seal was present in 4 (8%) websites analyzed. Readability was difficult and at the level of college students. CONCLUSIONS: The overall quality of patient-oriented online information on CRS-HIPEC is poor and available resources may not be comprehensible to the general public. Patients seeking information on CRS-HIPEC should be directed to sites affiliated with foundation/advocacy organizations.


Subject(s)
Comprehension , Hyperthermic Intraperitoneal Chemotherapy , Humans , Cytoreduction Surgical Procedures , Search Engine , Internet
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