56 research outputs found
Focal Laser Photocoagulation for Diabetic Macular Edema Done by Resident Physicians: Predictors of Effective Treatment
Purpose: To evaluate the effectiveness of focal laser for the treatment of diabetic macular edema (DME) performed by ophthalmology residents.
Methods: This retrospective chart review studies DME patients treated in a resident clinic with focal laser. Visual acuity (VA), OCT central subfield thickness (CST), and maximum subfield thickness (MST) at initial, 1-month, and 6-month visits were recorded.
Results: For 32 reviewed patients, the average VA was 20/58 initially and 20/39 at 6 months (p=0.18). Mean CST was 311 µm initially and 305 µm at 6 months (p=0.09). Mean MST was 413 µm initially and 382 µm at 6 months (p=0.007). Factors favoring success are initial CST \u3c400 µm, treatment of localized microaneurysms, and prior focal laser treatments.
Conclusion: Focal laser performed by residents was effective in decreasing MST and maintained visual acuity. Initial CST, localized microaneurysms, and repeat focal treatment predicted improved outcomes
Increasing physical activity and decreasing sedentary activity in adolescent girls – The Incorporating More Physical Activity and Calcium in Teens (IMPACT) study
<p>Abstract</p> <p>Background</p> <p>Lack of regular physical activity and consequent sub-optimal bone mass acquisition in youth has been implicated as a primary cause of adult-onset osteoporosis. IMPACT was a behavioral theory-based 1 1/2 year randomized controlled field study aimed at increasing bone accretion in middle school girls. The objective of this study was to determine the intervention effects of the IMPACT program upon key physical and sedentary activity endpoints among schools that participated in the IMPACT study. Endpoints examined included weight bearing physical activity (WBPA); moderate to vigorous physical activity (MVPA); vigorous physical activity (VPA); MET (metabolic equivalent) – weighted WBPA and MVPA; sedentary activity; before/after-school physical activity; and weekend physical activity.</p> <p>Methods</p> <p>Primary data analysis using a pretest-posttest control group design was conducted utilizing mixed model analysis of covariance. Data gathered from the IMPACT cohort from 2000–2002 were analyzed to determine baseline versus follow-up differences in activity endpoints. Confounders investigated included ethnicity, body mass index, menarcheal status, participation in 7<sup>th </sup>grade PE/athletics, friend/familial support and neighborhood safety.</p> <p>Results</p> <p>Follow-up means were higher for participating intervention schools relative to control schools for all physical activity variables but were statistically significant only for the following variables: daily minutes of vigorous physical activity (mean difference between Intervention (I) and Control (C) = 6.00↑ minutes, 95% CI = 5.82–6.18, p = 0.05), daily after school activity minutes (mean difference between I and C = 8.95↑ minutes, 95% CI = 8.69–9.21, p = 0.04), and daily weekend activity minutes (mean difference between I and C = 19.00↑ minutes, 95% CI = 18.40–19.60, p = 0.05). The intervention significantly reduced duration of student daily TV/Video watching (mean difference between I and C = 12.11↓ minutes, 95% CI = 11.74–12.48, p = 0.05) and total daily sedentary activity minutes (mean difference between I and C = 16.99↓ minutes, 95% CI = 16.49–17.50, p = 0.04).</p> <p>Conclusion</p> <p>A well designed and implemented school based health and physical activity intervention can result in a positive influence upon increasing physical activity levels and decreasing sedentary activity. Future interventions should consider a more structured intervention component to obtain significant changes in WBPA.</p
Functional traits influence patterns in vegetative and reproductive plant phenology – a multi-botanical garden study
1. Phenology has emerged as key indicator of the biological impacts of climate change, yet the role of functional traits constraining variation in herbaceous species’ phenology has received little attention. Botanical gardens are ideal places in which to investigate large numbers of species growing under common climate conditions. We ask whether interspecific variation in plant phenology is influenced by differences in functional traits.
2. We recorded onset, end, duration and intensity of initial growth, leafing out, leaf senescence, flowering and fruiting for 212 species across five botanical gardens in Germany. We measured functional traits, including plant height, absolute and specific leaf area, leaf dry matter content, leaf carbon and nitrogen content and seed mass and accounted for species’ relatedness.
3. Closely related species showed greater similarities in timing of phenological events than expected by chance, but species' traits had a high degree of explanatory power, pointing to paramount importance of species’ life-history strategies. Taller plants showed later timing of initial growth, and flowered, fruited and underwent leaf senescence later. Large-leaved species had shorter flowering and fruiting durations.
4. Taller, large-leaved species differ in their phenology and are more competitive than smaller, small-leaved species. We assume climate warming will change plant communities’ competitive hierarchies with consequences for biodiversity
The PhenObs initiative: A standardised protocol for monitoring phenological responses to climate change using herbaceous plant species in botanical gardens
Changes in phenology induced by climate change occur across the globe with important implications for ecosystem functioning and services, species performance and trophic interactions. Much of the work on phenology, especially leaf out and flowering, has been conducted on woody plant species. Less is known about the responses in phenology of herbaceous species induced by global change even though they represent a large and important part of biodiversity worldwide. A globally coordinated research effort is needed to understand the drivers and implications of such changes and to predict effects of global change on plant species phenology and related ecosystem processes.
Here, we present the rationale of the PhenObs initiative-botanical gardens as a global phenological observation network. The initiative aims to collect data on plant phenology in botanical gardens which will be used alongside information on plant traits and site conditions to answer questions related to the consequences of global change:
What is the variation in plant phenology in herbaceous species across the growing season and in response to changes in climate?
How can plant phenology be predicted from species' trait composition, provenance, position and extent of the distribution range and species' phylogeny?
What are the implications of this variation with respect to species performance and assembly, biotic interactions (e.g. plant-pollinator interactions) as well as ecosystem processes and services under changing land use and climate?
Here, we lay out the development of a straightforward protocol that is appropriate for monitoring phenology across a vast diversity of growth forms of herbaceous species from various habitats and geographical regions.
To focus on a key number of stages necessary to capture all aspects of plant species phenology, we analysed associations between 14 phenological stages. These data were derived from a 2-year study on 199 species in four German botanical gardens.
Based on the relationships of the phenological stages, we propose to monitor three vegetative stages ('initial growth', 'leaves unfolding' and 'senescence') and two reproductive stages ('flowers open' and 'ripe fruits') to fully capture herbaceous species phenology.
A free Plain Language Summary can be found within the Supporting Information of this article
Seasonal-to-interannual prediction of North American coastal marine ecosystems: forecast methods, mechanisms of predictability, and priority developments
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Jacox, M. G., Alexander, M. A., Siedlecki, S., Chen, K., Kwon, Y., Brodie, S., Ortiz, I., Tommasi, D., Widlansky, M. J., Barrie, D., Capotondi, A., Cheng, W., Di Lorenzo, E., Edwards, C., Fiechter, J., Fratantoni, P., Hazen, E. L., Hermann, A. J., Kumar, A., Miller, A. J., Pirhalla, D., Buil, M. P., Ray, S., Sheridan, S. C., Subramanian, A., Thompson, P., Thorne, L., Annamalai, H., Aydin, K., Bograd, S. J., Griffis, R. B., Kearney, K., Kim, H., Mariotti, A., Merrifield, M., & Rykaczewski, R. Seasonal-to-interannual prediction of North American coastal marine ecosystems: forecast methods, mechanisms of predictability, and priority developments. Progress in Oceanography, 183, (2020): 102307, doi:10.1016/j.pocean.2020.102307.Marine ecosystem forecasting is an area of active research and rapid development. Promise has been shown for skillful prediction of physical, biogeochemical, and ecological variables on a range of timescales, suggesting potential for forecasts to aid in the management of living marine resources and coastal communities. However, the mechanisms underlying forecast skill in marine ecosystems are often poorly understood, and many forecasts, especially for biological variables, rely on empirical statistical relationships developed from historical observations. Here, we review statistical and dynamical marine ecosystem forecasting methods and highlight examples of their application along U.S. coastlines for seasonal-to-interannual (1–24 month) prediction of properties ranging from coastal sea level to marine top predator distributions. We then describe known mechanisms governing marine ecosystem predictability and how they have been used in forecasts to date. These mechanisms include physical atmospheric and oceanic processes, biogeochemical and ecological responses to physical forcing, and intrinsic characteristics of species themselves. In reviewing the state of the knowledge on forecasting techniques and mechanisms underlying marine ecosystem predictability, we aim to facilitate forecast development and uptake by (i) identifying methods and processes that can be exploited for development of skillful regional forecasts, (ii) informing priorities for forecast development and verification, and (iii) improving understanding of conditional forecast skill (i.e., a priori knowledge of whether a forecast is likely to be skillful). While we focus primarily on coastal marine ecosystems surrounding North America (and the U.S. in particular), we detail forecast methods, physical and biological mechanisms, and priority developments that are globally relevant.This study was supported by the NOAA Climate Program Office’s Modeling, Analysis, Predictions, and Projections (MAPP) program through grants NA17OAR4310108, NA17OAR4310112, NA17OAR4310111, NA17OAR4310110, NA17OAR4310109, NA17OAR4310104, NA17OAR4310106, and NA17OAR4310113. This paper is a product of the NOAA/MAPP Marine Prediction Task Force
Crystal Structures of Two Aminoglycoside Kinases Bound with a Eukaryotic Protein Kinase Inhibitor
Antibiotic resistance is recognized as a growing healthcare problem. To address this issue, one strategy is to thwart the causal mechanism using an adjuvant in partner with the antibiotic. Aminoglycosides are a class of clinically important antibiotics used for the treatment of serious infections. Their usefulness has been compromised predominantly due to drug inactivation by aminoglycoside-modifying enzymes, such as aminoglycoside phosphotransferases or kinases. These kinases are structurally homologous to eukaryotic Ser/Thr and Tyr protein kinases and it has been shown that some can be inhibited by select protein kinase inhibitors. The aminoglycoside kinase, APH(3′)-IIIa, can be inhibited by CKI-7, an ATP-competitive inhibitor for the casein kinase 1. We have determined that CKI-7 is also a moderate inhibitor for the atypical APH(9)-Ia. Here we present the crystal structures of CKI-7-bound APH(3′)-IIIa and APH(9)-Ia, the first structures of a eukaryotic protein kinase inhibitor in complex with bacterial kinases. CKI-7 binds to the nucleotide-binding pocket of the enzymes and its binding alters the conformation of the nucleotide-binding loop, the segment homologous to the glycine-rich loop in eurkaryotic protein kinases. Comparison of these structures with the CKI-7-bound casein kinase 1 reveals features in the binding pockets that are distinct in the bacterial kinases and could be exploited for the design of a bacterial kinase specific inhibitor. Our results provide evidence that an inhibitor for a subset of APHs can be developed in order to curtail resistance to aminoglycosides
Drug resistance mutations and heteroresistance detected using the GenoType MTBDRplus assay and their implication for treatment outcomes in patients from Mumbai, India
<p>Abstract</p> <p>Background</p> <p>Only 5% of the estimated global multidrug resistant TB (MDRTB) load is currently detected. Endemic Mumbai with increasing MDR would benefit from the introduction of molecular methods to detect resistance.</p> <p>Methods</p> <p>The GenoType MTBDR<it>plus </it>assay was used to determine mutations associated with isoniazid and rifampicin resistance and their correlation with treatment outcomes. It was performed on a convenience sample comprising 88 onset and 67 fifth month isolates for which phenotypic drug susceptibility testing (DST) was determined by the Buddemeyer technique for an earlier study. Simultaneous presence of wild type and mutant bands was referred to as "mixed patterns" (heteroresistance).</p> <p>Results</p> <p>Phenotypically 41 isolates were sensitive; 11 isoniazid, 2 rifampicin, 2 pyrazinamide and 5 ethambutol monoresistant; 16 polyresistant and 78 MDR. The agreement between both methods was excellent (kappa = 0.72-0.92). Of 22 rifampicin resistant onset isolates, the predominant <it>rpoB </it>mutations were the singular lack of WT8 (n = 8) and mixed D516V patterns (n = 9). Of the 64 rifampicin resistant fifth month isolates, the most frequent mutations were in WT8 (n = 31) with a further 9 showing the S531L mutation. Mixed patterns were seen in 22 (34%) isolates, most frequently for the D516V mutation (n = 21). Of the 22 onset and 35 fifth month <it>katG </it>mutants, 13 and 12 respectively showed the S315T1 mutation with loss of the WT. Mixed patterns involving both S315T1 and S315T2 were seen in 9 and 23 isolates respectively. Seventeen of 23 and 23/35 <it>inhA </it>mutant onset and fifth month isolates showed mixed A16G profiles. Additionally, 10 fifth month isolates lacked WT2. Five onset and 6 fifth month isolates had both <it>katG </it>and <it>inhA </it>mutations. An association was noted between only <it>katG </it>but not only <it>inhA </it>resistance and poor outcome (<it>p </it>= 0.037); and additional resistance to ethambutol (<it>p </it>= 0.0033). More fifth month than onset isolates had mixed profiles for at least 1 gene (<it>p </it>= 0.000001).</p> <p>Conclusions</p> <p>The use of the assay to rapidly diagnose MDR could guide simultaneous first- and second-line DST, and reduce the delay in administering appropriate regimens. Furthermore, detection of heteroresistance could prevent inaccurate "cured" treatment outcomes documented through smear microscopy and permit more sensitive detection of neonascent resistance.</p
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
Substrate promiscuity of an aminoglycoside antibiotic resistance enzyme via target mimicry
The misuse of antibiotics has selected for bacteria that have evolved mechanisms for evading the effects of these drugs. For aminoglycosides, a group of clinically important bactericidal antibiotics that target the A-site of the 16S ribosomal RNA, the most common mode of resistance is enzyme-catalyzed chemical modification of the drug. While aminoglycosides are structurally diverse, a single enzyme can confer resistance to many of these antibiotics. For example, the aminoglycoside kinase APH(3′)-IIIa, produced by pathogenic Gram-positive bacteria such as enterococci and staphylococci, is capable of detoxifying at least 10 distinct aminoglycosides. Here we describe the crystal structures of APH(3′)-IIIa in complex with ADP and kanamycin A or neomycin B. These structures reveal that the basis for this enzyme’s substrate promiscuity is the presence of two alternative subsites in the antibiotic binding pocket. Furthermore, comparison between the A-site of the bacterial ribosome and APH(3′)-IIIa shows that mimicry is the second major factor in dictating the substrate spectrum of APH(3′)-IIIa. These results suggest a potential strategy for drug design aimed at circumventing antibiotic resistance
Structural Basis of APH(3′)-IIIa-Mediated Resistance to N1-Substituted Aminoglycoside Antibiotics▿ †
Butirosin is unique among the naturally occurring aminoglycosides, having a substituted amino group at position 1 (N1) of the 2-deoxystreptamine ring with an (S)-4-amino-2-hydroxybutyrate (AHB) group. While bacterial resistance to aminoglycosides can be ascribed chiefly to drug inactivation by plasmid-encoded aminoglycoside-modifying enzymes, the presence of an AHB group protects the aminoglycoside from binding to many resistance enzymes, and hence, the antibiotic retains its bactericidal properties. Consequently, several semisynthetic N1-substituted aminoglycosides, such as amikacin, isepamicin, and netilmicin, were developed. Unfortunately, butirosin, amikacin, and isepamicin are not resistant to inactivation by 3′-aminoglycoside O-phosphotransferase type IIIa [APH(3′)-IIIa]. We report here the crystal structure of APH(3′)-IIIa in complex with an ATP analog, AMPPNP [adenosine 5′-(β,γ-imido)triphosphate], and butirosin A to 2.4-Å resolution. The structure shows that butirosin A binds to the enzyme in a manner analogous to other 4,5-disubstituted aminoglycosides, and the flexible antibiotic-binding loop is key to the accommodation of structurally diverse substrates. Based on the crystal structure, we have also constructed a model of APH(3′)-IIIa in complex with amikacin, a commonly used semisynthetic N1-substituted 4,6-disubstituted aminoglycoside. Together, these results suggest a strategy to further derivatize the AHB group in order to generate new aminoglycoside derivatives that can elude inactivation by resistance enzymes while maintaining their ability to bind to the ribosomal A site
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