Global and regional prevalence of polypharmacy and related factors, 1997-2022: An umbrella review.

OBJECTIVE: Limited comprehensive evidence exists on the global prevalence of polypharmacy. This knowledge gap contributes to increased healthcare system costs and related public health concerns. Thus, we aimed to synthesize the current evidence on polypharmacy prevalence and associated factors in the general and older populations using an umbrella review. METHODS: Our primary outcomes were global prevalence and related indicators of polypharmacy. We systematically searched Google Scholar, PubMed/MEDLINE, Embase, and CINAHL for studies published between the inception of each database until April 30, 2023. RESULTS: Eleven meta-analyses incorporating 295 studies and 59,552,762 participants from 41 countries across six continents were identified. The global prevalence of polypharmacy in the general population is 37 %, with higher rates in older individuals (45 %), outpatients (48 %), and inpatients (52 %). North America showed a higher prevalence (52 %) than Asia (36 %) and Europe (36 %). Among frail elderly individuals, the prevalence of polypharmacy is 59 %, with the highest rates in Europe (68 %) and hospital settings (71 %). CONCLUSION: The global prevalence of polypharmacy and its associated factors in older adults present a complex, multifaceted, and conflicting picture. Understanding the prevalence of polypharmacy and its associated factors may help reduce the number of multidrug prescriptions.

Prenatal opioid exposure and subsequent risk of neuropsychiatric disorders in children: nationwide birth cohort study in South Korea.

OBJECTIVE: To investigate the potential association between prenatal opioid exposure and the risk of neuropsychiatric disorders in children. DESIGN: Nationwide birth cohort study. SETTING: From 1 January 2009 to 31 December 2020, birth cohort data of pregnant women in South Korea linked to their liveborn infants from the National Health Insurance Service of South Korea were collected. PARTICIPANTS: All 3 251 594 infants (paired mothers, n=2 369 322; age 32.1 years (standard deviation 4.2)) in South Korea from the start of 2010 to the end of 2017, with follow-up from the date of birth until the date of death or 31 December 2020, were included. MAIN OUTCOME MEASURES: Diagnosis of neuropsychiatric disorders in liveborn infants with mental and behaviour disorders (International Classification of Diseases 10th edition codes F00-99). Follow-up continued until the first diagnosis of neuropsychiatric disorder, 31 December 2020 (end of the study period), or the date of death, whichever occurred first. Eight cohorts were created: three cohorts (full unmatched, propensity score matched, and child screening cohorts) were formed, all of which were paired with sibling comparison cohorts, in addition to two more propensity score groups. Multiple subgroup analyses were performed. RESULTS: Of the 3 128 571 infants included (from 2 299 664 mothers), we identified 2 912 559 (51.3% male, 48.7% female) infants with no prenatal opioid exposure and 216 012 (51.2% male, 48.8% female) infants with prenatal opioid exposure. The risk of neuropsychiatric disorders in the child with prenatal opioid exposure was 1.07 (95% confidence interval 1.05 to 1.10) for fully adjusted hazard ratio in the matched cohort, but no significant association was noted in the sibling comparison cohort (hazard ratio 1.00 (0.93 to 1.07)). Prenatal opioid exposure during the first trimester (1.11 (1.07 to 1.15)), higher opioid doses (1.15 (1.09 to 1.21)), and long term opioid use of 60 days or more (1.95 (1.24 to 3.06)) were associated with an increased risk of neuropsychiatric disorders in the child. Prenatal opioid exposure modestly increased the risk of severe neuropsychiatric disorders (1.30 (1.15 to 1.46)), mood disorders, attention deficit hyperactivity disorder, and intellectual disability in the child. CONCLUSIONS: Opioid use during pregnancy was not associated with a substantial increase in the risk of neuropsychiatric disorders in the offspring. A slightly increased risk of neuropsychiatric disorders was observed, but this should not be considered clinically meaningful given the observational nature of the study, and limited to high opioid dose, more than one opioid used, longer duration of exposure, opioid exposure during early pregnancy, and only to some neuropsychiatric disorders.

Prenatal and postnatal factors associated with sudden infant death syndrome: an umbrella review of meta-analyses.

BACKGROUND: Comprehensive quantitative evidence on the risk and protective factors for sudden infant death syndrome (SIDS) effects is lacking. We investigated the risk and protective factors related to SIDS. METHODS: We conducted an umbrella review of meta-analyses of observational and interventional studies assessing SIDS-related factors. PubMed/MEDLINE, Embase, EBSCO, and Google Scholar were searched from inception until January 18, 2023. Data extraction, quality assessment, and certainty of evidence were assessed by using A Measurement Tool Assessment Systematic Reviews 2 following PRISMA guidelines. According to observational evidence, credibility was graded and classified by class and quality of evidence (CE; convincing, highly suggestive, suggestive, weak, or not significant). Our study protocol was registered with PROSPERO (CRD42023458696). The risk and protective factors related to SIDS are presented as equivalent odds ratios (eORs). RESULTS: We identified eight original meta-analyses, including 152 original articles, covering 12 unique risk and protective factors for SIDS across 21 countries/regions and five continents. Several risk factors, including prenatal drug exposure [eOR = 7.84 (95% CI = 4.81-12.79), CE = highly suggestive], prenatal opioid exposure [9.55 (95% CI = 4.87-18.72), CE = suggestive], prenatal methadone exposure [9.52 (95% CI = 3.34-27.10), CE = weak], prenatal cocaine exposure [4.38 (95% CI = 1.95-9.86), CE = weak], prenatal maternal smoking [2.25 (95% CI = 1.95-2.60), CE = highly suggestive], postnatal maternal smoking [1.97 (95% CI = 1.75-2.22), CE = weak], bed sharing [2.89 (95% CI = 1.81-4.60), CE = weak], and infants found with heads covered by bedclothes after last sleep [11.01 (95% CI = 5.40-22.45), CE = suggestive], were identified. On the other hand, three protective factors, namely, breastfeeding [0.57 (95% CI = 0.39-0.83), CE = non-significant], supine sleeping position [0.48 (95% CI = 0.37-0.63), CE = suggestive], and pacifier use [0.44 (95% CI = 0.30-0.65), CE = weak], were also identified. CONCLUSIONS: Based on the evidence, we propose several risk and protective factors for SIDS. This study suggests the need for further studies on SIDS-related factors supported by weak credibility, no association, or a lack of adequate research.

Efficacy of information and communication technology interventions for the management of diabetes mellitus: An umbrella review and evidence map.

INTRODUCTION: We validated the quality of evidence and potential benefits of information and communication technology interventions on diabetes-related health outcomes. METHODS: We systematically searched PubMed/MEDLINE, Embase, Google Scholar, and CINAHL and manually searched the reference lists of the retrieved review articles from each database's inception to October 2022. Randomized controlled trials were included to determine the benefits of information and communication technology interventions on diabetes outcomes. RESULTS: Ten meta-analyses of randomized controlled trials were included, with 37 unique outcomes encompassing 379 studies and >70,000 participants across 47 countries and six continents. Information and communication technology intervention was associated with reduced HbA1c levels in patients with type 1 (moderate certainty), type 2 (moderate certainty), and gestational diabetes (low certainty) and showed potential benefits for type 2 diabetes, demonstrating a reduction in systolic blood pressure (high certainty), low-density lipoprotein cholesterol (low certainty), and body weight (low certainty), whereas those for gestational diabetes demonstrated a reduction in fasting (low certainty) and 2-h postprandial blood glucose levels (low certainty). CONCLUSION: This umbrella review and evidence map revealed varying evidence on the potential benefits of information and communication technology interventions for diabetes-related outcomes. Our results demonstrate these interventions to be novel treatment options for policymakers and physicians to establish personalized health strategies.

Machine Learning-Based Prediction of Suicidality in Adolescents With Allergic Rhinitis: Derivation and Validation in 2 Independent Nationwide Cohorts.

BACKGROUND: Given the additional risk of suicide-related behaviors in adolescents with allergic rhinitis (AR), it is important to use the growing field of machine learning (ML) to evaluate this risk. OBJECTIVE: This study aims to evaluate the validity and usefulness of an ML model for predicting suicide risk in patients with AR. METHODS: We used data from 2 independent survey studies, Korea Youth Risk Behavior Web-based Survey (KYRBS; n=299,468) for the original data set and Korea National Health and Nutrition Examination Survey (KNHANES; n=833) for the external validation data set, to predict suicide risks of AR in adolescents aged 13 to 18 years, with 3.45% (10,341/299,468) and 1.4% (12/833) of the patients attempting suicide in the KYRBS and KNHANES studies, respectively. The outcome of interest was the suicide attempt risks. We selected various ML-based models with hyperparameter tuning in the discovery and performed an area under the receiver operating characteristic curve (AUROC) analysis in the train, test, and external validation data. RESULTS: The study data set included 299,468 (KYRBS; original data set) and 833 (KNHANES; external validation data set) patients with AR recruited between 2005 and 2022. The best-performing ML model was the random forest model with a mean AUROC of 84.12% (95% CI 83.98%-84.27%) in the original data set. Applying this result to the external validation data set revealed the best performance among the models, with an AUROC of 89.87% (sensitivity 83.33%, specificity 82.58%, accuracy 82.59%, and balanced accuracy 82.96%). While looking at feature importance, the 5 most important features in predicting suicide attempts in adolescent patients with AR are depression, stress status, academic achievement, age, and alcohol consumption. CONCLUSIONS: This study emphasizes the potential of ML models in predicting suicide risks in patients with AR, encouraging further application of these models in other conditions to enhance adolescent health and decrease suicide rates.

Development of polysaccharide-complexed nano-sized rice protein dispersion.

The objective of this study was to improve water solubility of the rice protein (RP) by forming complexes with anionic polysaccharides, such as sodium alginate (SA) and xanthan gum (XG). In addition, utilization of the RP complexes as an emulsifier was evaluated. The prepared RP-SA or RP-XG complexes were analyzed by measuring their particle size, ζ-potential, and water solubility as well as by confocal laser scanning microscopy. The formation of a complex between RP-SA and RP-XG improved the water solubility and dispersibility of RP over a wide range of pH values (3, 5, 7, and 9). Confocal fluorescence images showed that the aggregation of RP molecules was prevented by the formation of complexes between RP and polysaccharides. When soybean oil-in-water emulsions were prepared with complexes, RP-SA (ratio 4:1) and RP-XG(ratio 4:1) complex-stabilized emulsions were stable for 4 weeks of storage.

Real-Time Monitoring of Colorectal Cancer Location and Lymph Node Metastasis and Photodynamic Therapy Using Fucoidan-Based Therapeutic Nanogel and Near-Infrared Fluorescence Diagnostic-Therapy System.

We report real-time monitoring of colorectal cancer, lymph node metastasis of colorectal cancer cells, and tumor growth inhibition through photodynamic therapy (PDT) using a near-infrared fluorescence diagnostic-therapy system with a light source for PDT and a fucoidan-based theranostic nanogel (CFN-gel) with good accumulation efficiency in cancer cells. To confirm the effect of the fabricated system and developed CFN-gel, in vitro and in vivo experiments were performed. Chlorin e6 (Ce6) and 5-aminolevulinic acid (5-ALA) were used for comparison. We confirmed that CFN-gel has a high accumulation efficiency in cancer cells and high fluorescence signals in near-infrared light for a long period, and only CFN-gel delayed the growth rate of cancer in terms of its size in PDT. In addition, using the near-infrared fluorescence diagnostic-therapy system and CFN-gel prepared for these experiments, the lymph node metastasis of cancer cells was imaged in real time, and the metastasis was confirmed through H&E staining. The possibility of image-guided surgery and identification of lymph node metastasis in colorectal cancer can be confirmed through CFN-gel and a near-infrared fluorescence diagnostic-therapy system that includes various light sources.

Prediction of Specific Anxiety Symptoms and Virtual Reality Sickness Using In Situ Autonomic Physiological Signals During Virtual Reality Treatment in Patients With Social Anxiety Disorder: Mixed Methods Study.

BACKGROUND: Social anxiety disorder (SAD) is the fear of social situations where a person anticipates being evaluated negatively. Changes in autonomic response patterns are related to the expression of anxiety symptoms. Virtual reality (VR) sickness can inhibit VR experiences. OBJECTIVE: This study aimed to predict the severity of specific anxiety symptoms and VR sickness in patients with SAD, using machine learning based on in situ autonomic physiological signals (heart rate and galvanic skin response) during VR treatment sessions. METHODS: This study included 32 participants with SAD taking part in 6 VR sessions. During each VR session, the heart rate and galvanic skin response of all participants were measured in real time. We assessed specific anxiety symptoms using the Internalized Shame Scale (ISS) and the Post-Event Rumination Scale (PERS), and VR sickness using the Simulator Sickness Questionnaire (SSQ) during 4 VR sessions (#1, #2, #4, and #6). Logistic regression, random forest, and naïve Bayes classification classified and predicted the severity groups in the ISS, PERS, and SSQ subdomains based on in situ autonomic physiological signal data. RESULTS: The severity of SAD was predicted with 3 machine learning models. According to the F1 score, the highest prediction performance among each domain for severity was determined. The F1 score of the ISS mistake anxiety subdomain was 0.8421 using the logistic regression model, that of the PERS positive subdomain was 0.7619 using the naïve Bayes classifier, and that of total VR sickness was 0.7059 using the random forest model. CONCLUSIONS: This study could predict specific anxiety symptoms and VR sickness during VR intervention by autonomic physiological signals alone in real time. Machine learning models can predict the severe and nonsevere psychological states of individuals based on in situ physiological signal data during VR interventions for real-time interactive services. These models can support the diagnosis of specific anxiety symptoms and VR sickness with minimal participant bias. TRIAL REGISTRATION: Clinical Research Information Service KCT0003854; https://cris.nih.go.kr/cris/search/detailSearch.do/13508.

Deletion of ATAD3A inhibits osteogenesis by impairing mitochondria structure and function in pre-osteoblast.

BACKGROUND: ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear encoded mitochondrial membrane protein that spans inner and outer membrane, and it has been shown to regulate mitochondrial dynamics and cholesterol metabolism. Since the mitochondrial functions have been implicated for osteogenic differentiation, a role of ATAD3A in skeletal development has been investigated. RESULTS: Mesenchyme-specific ATAD3 knockout mice displayed severe defects in skeletal development. Additionally, osteoblast-specific deletion of ATAD3 in mice caused significant reduction in bone mass, while cartilage-specific ATAD3 knockout mice did not show any significant phenotypes. Consistent with these in vivo findings, ATAD3A knockdown impaired mitochondrial morphology and function in calvarial pre-osteoblast cultures, which, in turn, suppressed osteogenic differentiation in vitro. CONCLUSIONS: The current findings suggest that ATAD3A plays a crucial role in mitochondria homeostasis, which is required for osteogenic differentiation during skeletal development.

Spine Stereotactic Body Radiotherapy to Three or More Contiguous Vertebral Levels.

Background: With survival improving in many metastatic malignancies, spine metastases have increasingly become a source of significant morbidity; achieving durable local control (LC) is critical. Stereotactic body radiotherapy (SBRT) may offer improved LC and/or symptom palliation. However, due to setup concerns, SBRT is infrequently offered to patients with ≥3 contiguous involved levels. Because data are limited, we sought to evaluate the feasibility, toxicity, and cancer control outcomes of spine SBRT delivered to ≥3 contiguous levels. Methods: We retrospectively identified all SBRT courses delivered between 2013 and 2019 at a tertiary care institution for postoperative or intact spine metastases. Radiotherapy was delivered to 14-35 Gy in 1-5 fractions. Patients were stratified by whether they received SBRT to 1-2 or ≥3 contiguous levels. The primary endpoint was 1-year LC and was compared between groups. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity was assessed. In-depth dosimetric data were collected. Results: Overall, 165 patients with 194 SBRT courses were identified [54% were men, median age was 61 years, 93% had Karnofsky Performance Status (KPS) ≥70, and median follow-up was 15 months]. One hundred thirteen patients (68%) received treatment to 1-2 and 52 to 3-7 (32%) levels. The 1-year LC was 88% (89% for 1-2 levels vs. 84% for ≥3 levels, p = 0.747). On multivariate analysis, uncontrolled systemic disease was associated with inferior LC for patients with ≥3 treated levels. No other demographic, disease, treatment, or dosimetric variables achieved significance. Rates of new/progressive fracture were equivalent (8% vs. 9.5%, p = 0.839). There were no radiation-induced myelopathy or grade 3+ acute or late toxicities in either group. Coverage of ≥95% of the planning target volume with ≥95% prescription dose was similar between groups (96% 1-2 levels vs. 89% ≥3 levels, p = 0.078). Conclusions: For patients with ≥3 contiguous involved levels, spine SBRT is feasible and may offer excellent LC without significant toxicity. Prospective evaluation is warranted.

A proof of concept treatment planning study of gated proton radiotherapy for cardiac soft tissue sarcoma.

BACKGROUND AND PURPOSE: Few studies on radiotherapy of cardiac targets exist, and none using a gating method according to cardiac movement. This study aimed to evaluate the dose-volume advantage of using cardiac-respiratory double gating (CRDG) in terms of target location with additional ECG signals in comparison to respiratory single gating (RSG) for proton radiotherapy of targets in the heart. MATERIALS AND METHODS: Cardiac motion was modeled using a cardiac-gated four-dimensional computed tomography scan obtained at the end-expiration. Plans with the prescription dose of 50 Gy (RSG and CRDG plans at diastole and systole phases) were compared in terms of clinically relevant dose-volume criteria for various target sizes and seven cardiac subsites. Potential dose sparing by utilizing CRDG over RSG was quantified in terms of surrounding organ at risk (OAR) doses while the dose coverage to the targets was fully ensured. RESULTS: The average mean dose reductions were 28 ± 10% when gated at diastole and 21 ± 12% at systole in heart and 30 ± 17% at diastole and 8 ± 9% at systole in left ventricle compared to respiratory single gating. The diastole phase was optimal for gated treatments for all target locations except right ventricle and interventricular septum. The right ventricle target was best treated at the systole phase. However, an optimal gating phase for the interventricular septum target could not be determined. CONCLUSIONS: We have studied the dose-volume benefits of CRDG for each cardiac subsite, and demonstrated that CRDG may spare organs at risk better than RSG.

Biomolecular imaging of colorectal tumor lesions using a FITC-labeled scFv-Cκ fragment antibody.

For the sensitive diagnosis of colorectal cancer lesions, advanced molecular imaging techniques using cancer-specific targets have emerged. However, issues regarding the clearance of unbound probes and immunogenicity remain unresolved. To overcome these limitations, we developed a small-sized scFv antibody fragment conjugated with FITC for the real-time detection of colorectal cancer by in vivo molecular endoscopy imaging. A small-sized scFv fragment can target colon cancer secreted protein-2 (CCSP-2), highly expressed in colorectal adenocarcinoma tissues; moreover, its full-length IgG probe has been used for molecular imaging previously. To assess the efficacy of anti-CCSP-2 scFv-FITC, surgical specimens were obtained from 21 patients with colorectal cancer for ex vivo molecular fluorescence analysis, histology, and immunohistochemistry. Orthotopic mice were administered with anti-CCSP-2 scFv-FITC topically and intravenously, and distinct tumor lesions were observed by real-time fluorescence colonoscopy. The fluorescence imaging of human colon cancer specimens allowed the differentiation of malignant tissues from non-malignant tissues (p < 0.05), and the CCSP-2 expression level was found to be correlated with the fluorescence intensity. Here, we demonstrated the feasibility and safety of anti-CCSP-2 scFv-FITC for molecular imaging as well as its potential in real-time fluorescence colonoscopy for the differential diagnosis of tumor lesions.

Fucoidan-Based Theranostic Nanogel for Enhancing Imaging and Photodynamic Therapy of Cancer.

In this study, a fucoidan-based theranostic nanogel (CFN-gel) consisting of a fucoidan backbone, redox-responsive cleavable linker and photosensitizer is developed to achieve activatable near-infrared fluorescence imaging of tumor sites and an enhanced photodynamic therapy (PDT) to induce the complete death of cancer cells. A CFN-gel has nanomolar affinity for P-selectin, which is overexpressed on the surface of tumor neovascular endothelial cells as well as many other cancer cells. Therefore, a CFN-gel can enhance tumor accumulation through P-selectin targeting and the enhanced permeation and retention effect. Moreover, a CFN-gel is non-fluorescent and non-phototoxic upon its systemic administration due to the aggregation-induced self-quenching in its fluorescence and singlet oxygen generation. After internalization into cancer cells and tumor neovascular endothelial cells, its photoactivity is recovered in response to the intracellular redox potential, thereby enabling selective near-infrared fluorescence imaging and an enhanced PDT of tumors. Since a CFN-gel also shows nanomolar affinity for the vascular endothelial growth factor, it also provides a significant anti-tumor effect in the absence of light treatment in vivo. Our study indicates that a fucoidan-based theranostic nanogel is a new theranostic material for imaging and treating cancer with high efficacy and specificity.

Cupriavidus sp. strain Ni-2 resistant to high concentration of nickel and its genes responsible for the tolerance by genome comparison.

The widespread use of metals influenced many researchers to examine the relationship between heavy metal toxicity and bacterial resistance. In this study, we have inoculated heavy metal-contaminated soil from Janghang region of South Korea in the nickel-containing media (20 mM Ni2+) for the enrichment. Among dozens of the colonies acquired from the several transfers and serial dilutions with the same concentrations of Ni, the strain Ni-2 was chosen for further studies. The isolates were identified for their phylogenetic affiliations using 16S rRNA gene analysis. The strain Ni-2 was close to Cupriavidus metallidurans and was found to be resistant to antibiotics of vancomycin, erythromycin, chloramphenicol, ampicillin, gentamicin, streptomycin, and kanamycin by disk diffusion method. Of the isolated strains, Ni-2 was sequenced for the whole genome, since the Ni-resistance seemed to be better than the other strains. From the genome sequence we have found that there was a total of 89 metal-resistance-related genes including 11 Ni-resistance genes, 41 heavy metal (As, Cd, Zn, Hg, Cu, and Co)-resistance genes, 22 cation-efflux genes, 4 metal pumping ATPase genes, and 11 metal transporter genes.

Porous platinum nanoparticles as a high-Z and oxygen generating nanozyme for enhanced radiotherapy in vivo.

Radiotherapy (RT), along with surgery and chemotherapy, is a major modality of cancer therapy. Nevertheless, insufficient deposition of radiation energy in tumors and hypoxia-associated radioresistance remain the greatest challenges in RT. Here, we propose porous platinum nanoparticles as a new nanomedicine platform for solving these two problems at the same time using a single agent. Because of the combined advantages of a high-Z element and oxygen generation capability, porous platinum nanoparticles can significantly increase radiation-induced DNA damage, ROS stress, and cell cycle arrest by effectively depositing X-ray radiation energy within the cancer cells. Further, porous platinum nanoparticles increase tumor oxygenation by converting endogenic H2O2 to O2, thus greatly enhancing RT with no apparent in vivo toxicity to animals. This study presents a new nanomedicine strategy based on the use of porous high-Z metal nanoparticles with oxygen generation function for the synergistic enhancement of RT in cancer treatment.

A cryogenically cooled high voltage DC photoemission electron source.

Linear electron accelerators and their applications such as ultrafast electron diffraction require compact high-brightness electron sources with high voltage and electric field at the photocathode to maximize the electron density and minimize space-charge induced emittance growth. Achieving high brightness from a compact source is a challenging task because it involves an often-conflicting interplay between various requirements imposed by photoemission, acceleration, and beam dynamics. Here we present a new design for a compact high voltage DC electron gun with a novel cryogenic photocathode system and report on its construction and commissioning process. This photoemission gun can operate at ∼200 kV at both room temperature and cryogenic temperature with a corresponding electric field of 10 MV/m, necessary for achieving high quality electron beams without requiring the complexity of guns, e.g., based on RF superconductivity. It hosts a compact photocathode plug compatible with that used in several other laboratories opening the possibility of generating and characterizing electron beam from photocathodes developed at other institutions.

Evaluation of the plant growth-promoting activity of Pseudomonas nitroreducens in Arabidopsis thaliana and Lactuca sativa.

KEY MESSAGE: Pseudomonas nitroreducens: strain IHB B 13561 (PnIHB) enhances the growth of Arabidopsis thaliana and Lactuca sativa via the stimulation of cell development and nitrate absorption. Plant growth-promoting rhizobacteria (PGPR) enhance plant development through various mechanisms; they improve the uptake of soil resources by plants to greatly promote plant growth. Here, we used Arabidopsis thaliana seedlings and Lactuca sativa to screen the growth enhancement activities of a purified PGPR, Pseudomonas nitroreducens strain IHB B 13561 (PnIHB). When cocultivated with PnIHB, both species of plants exhibited notably improved growth, particularly in regard to biomass. Quantitative reverse transcription polymerase chain reaction analysis indicated high expression levels of the nitrate transporter genes, especially NRT2.1, which plays a major role in the high-affinity nitrate transport system in roots. Moreover, enhanced activity of the cyclin-B1 promoter was observed when wild-type 'Columbia-0' Arabidopsis seedlings were exposed to PnIHB, whereas upregulation of cyclin-B also occurred in the inoculated lettuce seedlings. Overall, these results suggest that PnIHB improves A. thaliana and L. sativa growth via specific pathways involved in the promotion of cell development and enhancement of nitrate uptake.

Mutations in MetG (methionyl-tRNA synthetase) and TrmD [tRNA (guanine-N1)-methyltransferase] conferring meropenem tolerance in Burkholderia thailandensis.

Objectives: Although meropenem is widely used to treat Burkholderia infections, the response of Burkholderia pathogens to this antibiotic is largely unexplored. Methods: Burkholderia thailandensis, a model for Burkholderia spp., particularly Burkholderia mallei and Burkholderia pseudomallei, was challenged with a lethal level of meropenem and survivors were isolated. The genomes of two of the isolates were analysed to identify mutated genes and these genes were then specifically examined in more isolates to profile mutation diversity. Mutants were characterized to investigate the biological basis underlying survival against meropenem. Results: One of two genes associated with tRNA metabolism [metG or trmD, encoding methionyl-tRNA synthetase or tRNA (guanine-N1)-methyltransferase, respectively] was found to be mutated in the two survivors. A single nucleotide substitution and a frameshift mutation were found in metG and trmD, respectively. Five different substitution mutations affecting methionine- or tRNA-binding sites were found in metG during further screening. The mutants exhibited slowed growth and increased tolerance not only to meropenem but also various other antibiotics. This tolerance required intact RelA, a key stringent response. Conclusions: Specific mutations affecting the tRNA pool, particularly those in metG, play a pivotal role in the B. thailandensis response to meropenem challenge. This mechanism of antibiotic tolerance is important because it can reduce the effectiveness of meropenem and thereby facilitate chronic infection by Burkholderia pathogens. In addition, specific mutations found in MetG will prove useful in the effort to develop new drugs to completely inhibit this essential enzyme, while preventing stringent-response-mediated antibiotic tolerance in pathogens.

Dual Role of a Fluorescent Peptidyl Probe Based on Self-Assembly for the Detection of Heparin and for the Inhibition of the Heparin-Digestive Enzyme Reaction.

The detection of fluorescent probes for biomolecules and control of the function of a complex through a recognition process have not been investigated intensively. A fluorescent peptidyl probe (1) based on the self-assembly stimulated by heparin was synthesized. The fluorescent probe with an aggregation-induced emission fluorophore formed a self-assembling complex with heparin, resulting in a sensitive and selective turn-on response to heparin compared to its biological competitors. The detection limits for heparin were measured to be 138.0 pM (R2 = 0.976) in aqueous solution and 2.6 nM (R2 = 0.996) in aqueous solution containing human serum. Nanosized aggregates formed through the self-assembly of the complex showed potent resistance against the heparin-digestive enzyme. The dual role of the probe for the detection of heparin and the inhibition of heparinase-mediated digestion through the recognition process was used for the real-time monitoring of the enzyme activity of heparinase for the digestion of heparin. Furthermore, the dual role of the probe was applied for the detection of the oversulfated chondroitin sulfate contaminant in heparin.