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The Astronomical Journal 2019A relatively massive and moderately eccentric disk of trans-Neptunian objects (TNOs) can effectively counteract apse precession induced by the outer planets, and in the...
A relatively massive and moderately eccentric disk of trans-Neptunian objects (TNOs) can effectively counteract apse precession induced by the outer planets, and in the process shepherd highly eccentric members of its population into nearly stationary configurations that are antialigned with the disk itself. We were sufficiently intrigued by this remarkable feature to embark on an extensive exploration of the full spatial dynamics sustained by the combined action of giant planets and a massive trans-Neptunian debris disk. In the process, we identified ranges of disk mass, eccentricity, and precession rate that allow apse-clustered populations that faithfully reproduce key orbital properties of the much-discussed TNO population. The shepherding disk hypothesis is, to be sure, complementary to any potential ninth member of the solar system pantheon, and could obviate the need for it altogether. We discuss its essential ingredients in the context of solar system formation and evolution, and argue for their naturalness in view of the growing body of observational and theoretical knowledge about self-gravitating disks around massive bodies, extra-solar debris disks included.
PubMed: 33551453
DOI: 10.3847/1538-3881/aaf0fc -
Journal of AAPOS : the Official... Oct 2018To compare the optic disk features of preterm and term infants.
PURPOSE
To compare the optic disk features of preterm and term infants.
METHODS
Digital fundus images of preterm infants were compared with those of infants born at term, imaged within 1 week of birth. The optic disk horizontal diameter to vertical diameter ratio, the disk-macula to disk-diameter ratio, and the presence or absence of double ring sign was noted.
RESULTS
Images of 649 infants (324 preterm and 325 term) were analyzed. Of the preterm infants, 129 (40%) had a double ring sign, compared to 4% in term infants. The double ring was seen more frequently in infants of European descent and was more common with younger gestational age. The mean horizontal to vertical disk diameter in preterm infants on first examination was 0.75 ± 0.063, increasing to 0.80 ± 0.069 at final examination. Term infants had a horizontal to vertical disk diameter ratio of 0.79 ± 0.064. At final examination, the ratio of disk-to-macula distance to the horizontal disk diameter was 3.9 in preterm infants and 3.7 for term infants.
CONCLUSIONS
In our study population preterm infants often had a double ring sign around the optic disk in the absence of optic nerve hypoplasia. Preterm disks tend to be more vertically oval, which becomes less oval closer to term. The mean disk-to-macula to disk-diameter ratio among normal preterm infants was higher than previously reported.
Topics: Birth Weight; Female; Fundus Oculi; Gestational Age; Humans; Infant; Infant, Newborn; Infant, Premature; Macula Lutea; Male; Optic Disk; Retrospective Studies
PubMed: 30048679
DOI: 10.1016/j.jaapos.2018.04.008 -
Microbiology Spectrum Feb 2022The objective of this research was to evaluate the correlation between inhibitory zones and MIC when testing ceftazidime-avibactam using disk diffusion, Etest, and broth... (Comparative Study)
Comparative Study
The objective of this research was to evaluate the correlation between inhibitory zones and MIC when testing ceftazidime-avibactam using disk diffusion, Etest, and broth microdilution method established by the Clinical and Laboratory Standards Institute (CLSI). Four-hundred and 58 isolates of isolated from 54 medical centers from the China Antimicrobial Surveillance Network (CHINET) in 2016 to 2020 were collected. Antimicrobial susceptibility testing using broth microdilution, Etest, and disk diffusion were performed according to the CLSI. Of the 458 , 17.2% (79/458) and 82.8%(379/458) were resistant or susceptible to ceftazidime-avibactam by broth microdilution, respectively. Compared with the broth microdilution method, the categorical agreement (CA) and essential agreement (EA) of the Etest were 99.6% (456/458) and 94.8% (434/458), respectively; the major error (ME) and very major error (VME) were both 0.2% (1/458). For disk diffusion, the CA and VME were 99.8% (457/458) and 0.2% (1/458), respectively. For Escherichia coli, the CA and EA of the Etest were 100% and 97.1% (135/139), respectively. The CA of the disk diffusion was 100%. For Klebsiella pneumoniae, the CA and EA of the Etest were 99.3% (288/290) and 93.4% (271/290), respectively, the ME and VME were both 0.3% (1/290). The CA and VME of disk diffusion were 99.7% (289/290) and 0.3% (1/290), respectively. For other , the CA and EA of the Etest were 100% and 96.6% (28/29), respectively. The CA of the disk diffusion was 100%. Ceftazidime-avibactam disk diffusion (30/20-μg disks) and Etest demonstrated good performance for ceftazidime-avibactam susceptibility testing against clinical isolates. Multidrug-resistant Gram-negative bacteria, especially for extended-spectrum β-lactamases-producing and carbapenemase-producing , are disseminating rapidly around the world. Treatment options for these infections are limited, which prompt the development of novel or combinational therapies to combat the infections caused by multidrug-resistant pathogens. The newly available β-lactam combination agent ceftazidime-avibactam has been demonstrated good and activity against ESBL, AmpC, KPC-2, or OXA-48-like-producing isolates and has shown promise in treating carbapenem-resistant infections. Concerningly, there are few available automated systems for ceftazidime-avibactam susceptibility testing, and the broth microdilution method is hard to perform in most routine laboratories. Therefore, we urgently need an economical and practical method for the accurate detection of ceftazidime-avibactam activity against Gram-negative bacilli. Here, we evaluate the performance of the disk diffusion and Etest compared with the reference broth microdilution method against clinical strains.
Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Ceftazidime; Disk Diffusion Antimicrobial Tests; Drug Combinations; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Enterobacteriaceae Infections; Humans
PubMed: 35019685
DOI: 10.1128/spectrum.01092-21 -
Journal of Clinical Microbiology Jun 2017This study was conducted to determine the effect of testing parameters on the activity of gepotidacin, a new triazaacenaphthylene antibacterial agent for the treatment... (Comparative Study)
Comparative Study
This study was conducted to determine the effect of testing parameters on the activity of gepotidacin, a new triazaacenaphthylene antibacterial agent for the treatment of conventional and biothreat pathogens. CLSI methods, and variations of those methods, were used to test 10 , 10 , 10 , and 5 isolates by MIC and 30 , 15 , and 15 isolates by disk diffusion (DD) methods. Levofloxacin and linezolid were tested as comparator agents for MIC and DD methods, respectively. Broth microdilution (BMD), macrodilution (MD), and agar dilution (AD) methods were compared. Variations in media, temperature, incubation time, CO level, and inoculum concentration were tested by all methods, and variations in pH, calcium, magnesium, zinc, potassium, thymidine, and polysorbate 80 levels were tested by BMD and DD. The addition of albumin, serum, and lung surfactant was studied by BMD. The variables that impacted the results the most were high inoculum and pH 5.5 (no growth of and by BMD). Gepotidacin AD MIC levels were increased and disk zone diameters were decreased for all species in 10% CO incubation. The following variables had a minimal effect on gepotidacin results: pH, agar method, atmospheric condition, temperature, and addition of serum and albumin for broth methods. There were also some slight differences in gepotidacin disk results between disk manufacturers and some agar types and also with potassium and thymidine for For all other variations, gepotidacin MIC and disk results were considered comparable to reference results.
Topics: Acenaphthenes; Anti-Bacterial Agents; Bacteria; Heterocyclic Compounds, 3-Ring; Microbial Sensitivity Tests
PubMed: 28330893
DOI: 10.1128/JCM.02366-16 -
Journal of AAPOS : the Official... Feb 2020To compare the optic disks of children and adults with megalopapilla using optical coherence tomography (OCT). (Comparative Study)
Comparative Study
PURPOSE
To compare the optic disks of children and adults with megalopapilla using optical coherence tomography (OCT).
SUBJECTS AND METHODS
We conducted a case-control study of subjects with megalopapilla and normal sized disks seen between February 2013 and July 2015 at the Hospital da Luz, Lisbon. All subjects and controls were imaged with spectral domain OCT, and optic nerve head (ONH) parameters were evaluated. The main outcome measures were rim area, cup:disk ratio, and cup volume.
RESULTS
A total of 168 eyes of 168 subjects were included: 78 with megalopapilla (39 children/39 adults) and 90 (45/45) with normal sized disks. For the same ONH area, children had a higher rim area (P = 0.000), a smaller cup:disk ratio (P = 0.001), and a smaller cup volume (P = 0.001) than adults. For the same age group, megalopapilla had a larger cup:disk ratio (P = 0.000) and a larger cup volume (P = 0.000) than normal-sized disks.
CONCLUSIONS
In this study cohort, compared to adults with the same disk size, children (with megalopapilla or normal-sized disks) had a larger rim area and smaller cup. These findings suggest that enlargement of the cup of the optic disk and reduction of the rim area can occur through life.
Topics: Adolescent; Adult; Aging; Child; Female; Humans; Intraocular Pressure; Male; Middle Aged; Optic Disk; Optic Nerve Diseases; Retinal Ganglion Cells; Retrospective Studies; Tomography, Optical Coherence; Visual Fields; Young Adult
PubMed: 31926369
DOI: 10.1016/j.jaapos.2019.09.019 -
Clinical Spine Surgery May 2022This study was a post hoc analysis of data collected from 2 Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trials.
STUDY DESIGN
This study was a post hoc analysis of data collected from 2 Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trials.
OBJECTIVE
The purposes of this study were to: (1) measure disk space heights adjacent to the level to be treated with a total disk replacement (TDR); (2) analyze cervical disk space heights to be replaced with TDR; and (3) investigate the frequency of use of a smaller height TDR when available.
SUMMARY OF BACKGROUND DATA
Cervical TDR produces outcomes noninferior or superior to anterior cervical discectomy and fusion. While the restoration of the height of a collapsed, degenerated disk is a surgical goal, there are potential problems with overdistracting the segment with an implant.
METHODS
Disk heights were measured using radiographs from the 1-level Simplify Cervical Artificial Disk IDE trial, producing values for 259 levels adjacent to the treated level and 162 treated levels. The device is available in 4, 5, and 6 mm heights. The 4 mm height became available only after treatment was 13% complete in the single-level trial and was available for all of the 2-level trial.
RESULTS
Measurements of 259 adjacent levels found that 55.2% of disk spaces had a height of <4 mm. Among operated levels, 82.7% were <4 mm. When a 4 mm TDR was available, it was used in 38.4% of operated levels in the 1-level trial and 54.3% of levels in the 2-level trial.
CONCLUSIONS
Among nonoperated levels, 55.2% were of height <4 mm, suggesting that TDRs of greater heights may potentially overdistract the disk space. The 4 mm TDR was selected by surgeons in 49.4% of all implanted levels, suggesting a preference for smaller TDR height. Further investigation is warranted to determine if the lower height implants are related to clinical and/or radiographic outcomes.
LEVEL OF EVIDENCE
Level III.
Topics: Cervical Vertebrae; Diskectomy; Follow-Up Studies; Humans; Intervertebral Disc Degeneration; Prospective Studies; Range of Motion, Articular; Spinal Fusion; Total Disc Replacement; Treatment Outcome
PubMed: 35344516
DOI: 10.1097/BSD.0000000000001314 -
Journal of Clinical Microbiology Aug 2018Expedited pathways to antimicrobial agent approval by the U.S. Food and Drug Administration (FDA) have led to increased delays between drug approval and the availability... (Review)
Review
The Continued Value of Disk Diffusion for Assessing Antimicrobial Susceptibility in Clinical Laboratories: Report from the Clinical and Laboratory Standards Institute Methods Development and Standardization Working Group.
Expedited pathways to antimicrobial agent approval by the U.S. Food and Drug Administration (FDA) have led to increased delays between drug approval and the availability of FDA-cleared antimicrobial susceptibility testing (AST) devices. Antimicrobial disks for use with disk diffusion testing are among the first AST devices available to clinical laboratories. However, many laboratories are reluctant to implement disk diffusion testing for a variety of reasons, including dwindling proficiency with this method, interruptions of the laboratory workflow, uncertainty surrounding the quality and reliability of disk diffusion tests, and a perceived need to report MIC values to clinicians. This minireview provides a report from the Clinical and Laboratory Standards Institute Methods Development and Standardization Working Group on the current standards and clinical utility of disk diffusion testing.
Topics: Clinical Laboratory Techniques; Disk Diffusion Antimicrobial Tests; Humans; Reference Standards; Reproducibility of Results
PubMed: 29743302
DOI: 10.1128/JCM.00437-18 -
Current Microbiology May 2024Antimicrobial susceptibility testing (AST) by disk diffusion provides an accurate image of bacterial growth, enabling the detection of culture purity, heterogeneous...
Antimicrobial susceptibility testing (AST) by disk diffusion provides an accurate image of bacterial growth, enabling the detection of culture purity, heterogeneous growth, and antibiotic interactions. However, this manual method is time-consuming and visual interpretation is prone to errors. To overcome these disadvantages, the Radian® In-Line Carousel (Copan, Brescia, Italy) was launched, which is a WASPLab® module dedicated to full automation of (pre)-analytical steps as well as interpretation of disk diffusion AST. However, until now, no evaluation of Radian® against manual disk diffusion has been performed. We assessed the categorical agreement (CA) between standardized disk diffusion (reference method) and Radian® using EUCAST 2021 breakpoints. We tested 135 non-duplicate strains, selected from the National EUCAST challenge panel, clinical strains, and external quality controls. The strains included Enterobacterales (n = 63), Enterococcus faecalis (n = 3), Enterococcus faecium (n = 10), Pseudomonas aeruginosa (n = 16), Staphylococcus aureus (n = 19), coagulase-negative staphylococci (n = 4), and Streptococcus spp. (n = 20). Furthermore, we explored antibiotic disk thermolability in the WASP Radian® carousel by testing 10 ATCC® strains up to 7 days. The observed CA was 95.3%, 96.3%, 93.8%, 97.3% and 98.0% for Enterobacterales, Enterococcus spp., P. aeruginosa, Staphylococcus spp. and Streptococcus spp., respectively, resulting in an acceptable overall CA for all groups. (Very) major error rates were ≤ 5% for all antibiotics. Antibiotic disk thermostability was confirmed up to 4 days in the WASP Radian® In-Line Carousel. The Radian® In-Line Carousel provides a fully automated solution for accurate disk diffusion AST, reducing workload and improving standardization and traceability. In addition, our study demonstrated the thermostability of antibiotic disks up to 4 days in the WASP Radian® In-Line Carousel.
Topics: Anti-Bacterial Agents; Disk Diffusion Antimicrobial Tests; Bacteria; Humans; Microbial Sensitivity Tests; Automation, Laboratory
PubMed: 38816509
DOI: 10.1007/s00284-024-03710-z -
Spine Surgery and Related Research 2021Despite being originally developed for the evaluation of lumbar disk degeneration, the Pfirrmann classification has emerged as the most popular classification system for...
INTRODUCTION
Despite being originally developed for the evaluation of lumbar disk degeneration, the Pfirrmann classification has emerged as the most popular classification system for cervical disk degeneration. However, with the Suzuki classification, a new classification system that is specifically tailored for the evaluation of cervical disk disease was introduced. In this study, we aim to evaluate differences in inter- and intraobserver reliability of both classifications in a head-to-head comparison.
METHODS
In total, we have evaluated 120 cervical disks within 40 patients via magnetic resonance imaging according to the Pfirrmann and Suzuki classification. The degree of disk degeneration was evaluated by two independent musculoskeletal radiologists. After 6 months, the classification was reassessed to evaluate the intraobserver reliability. The inter- and intraobserver reliabilities were then calculated using Cohen's kappa.
RESULTS
The inter- and intraobserver reliability provided a significant agreement between all ratings in Pfirrmann as well as the Suzuki classification (p>0.001). The interobserver reliability was determined to be fair in both the Suzuki classification (κ=0.290) and the Pfirrmann classification (κ=0.265). The intraobserver reliability was substantial in the Suzuki classification (κ=0.798), while it was almost perfect in the Pfirrmann classification (κ=0.858).
CONCLUSIONS
Although not designed for the evaluation of cervical disk degeneration, the Pfirrmann classification yielded equal inter- and higher intraobserver reliability. Both classification systems are viable options for the grading of cervical disk degeneration. While the Pfirrmann classification has the advantage of being better established, the Suzuki classification may be clinically superior due to a better representation of cervical disk degeneration and the consideration of disk bulging for the classification of cervical disk degeneration.
PubMed: 34966859
DOI: 10.22603/ssrr.2021-0048 -
Journal of Spine Research and Surgery 2023Intervertebral disk degeneration (IDD) is an intricate pathological process contributing to one of the major causes of low back pain. The degradation of the...
Intervertebral disk degeneration (IDD) is an intricate pathological process contributing to one of the major causes of low back pain. The degradation of the extracellular matrix (ECM), inflammation, and apoptosis have all been investigated as critical factors involved in the pathology of degenerative disk disease. Additionally, the presence of aberrant microRNAs (miRNAs), conserved molecules that regulate the amount protein post-transcriptionally, may play a crucial role in the pathogenesis of IDD. Research regarding the dysfunction of miRNAs in IDD has been well researched over the past five years. Here, we provide a critical overview of the current knowledge of miRNAs, emphasizing the processes involved in the degenerative disk pathology.
PubMed: 36777190
DOI: 10.26502/fjsrs0051