Transcriptomic Profiling of Pleural Effusions: Differences in Malignant and Infectious Fluids.

Background and Objectives: Different cellular and molecular processes are involved in the production of malignant and infectious pleural effusions. However, the underlying mechanisms responsible for these differences or their consequences remain incompletely understood. The objective of this study was to identify differences in gene expression in pleural exudates of malignant and infectious aetiology and establish the possible different biological processes involved in both situations. Materials and Methods: RNA transcriptomic analysis was performed on 46 pleural fluid samples obtained during diagnostic thoracocenteses from 46 patients. There were 35 exudates (19 malignant and 16 infectious effusions) and 11 transudates that were used as a reference control group. Differential gene expression analysis for both exudative groups was identified. An enrichment score using the Human Kegg Orthology database was used for establishing the biological processes associated with malignant and infectious pleural effusions. Results: When comparing malignant exudates with infectious effusions, 27 differentially expressed genes with statistical significance were identified. Network analysis showed ten different biological processes for malignant and for infectious pleural effusions. In malignant fluids, processes related to protein synthesis and processing predominate. In infectious exudates, biological processes in connection with ATP production prevail. Conclusions: This study demonstrates differentially expressed genes in malignant and infectious pleural effusions, which could have important implications in the search for diagnostic or prognostic biomarkers. In addition, for the first time, biological processes involved in these two causes of pleural exudates have been described.

Flow Cytometry Analysis in Breast Implant-Associated Anaplastic Large Cell Lymphoma: Three Case Reports.

Breast Implant-Associated-Anaplastic Large Cell Lymphoma (BIA-ALCL) is a rare T-cell non-Hodgkin lymphoma associated with breast prosthetic implants and represents a diagnostic challenge. The National Comprehensive Cancer Network (NCCN) guidelines, updated in 2024, recommend for diagnosis an integrated work-up that should include cell morphology, CD30 immunohistochemistry (IHC), and flow cytometry (FCM). CD30 IHC, although the test of choice for BIA-ALCL diagnosis, is not pathognomonic, and this supports the recommendation to apply a multidisciplinary approach. A close collaboration between pathologists and laboratory professionals allowed the diagnosis of three BIA-ALCLs, presented as case reports, within a series of 35 patients subjected to periprosthetic effusions aspiration from 2018 to 2023. In one case, rare neoplastic cells were identified by FCM, and this result was essential in leading the anatomopathological picture as indicative of this neoplasm. In fact, the distinction between a lymphomatous infiltrate from reactive cells may be very complex in the cytopathology and IHC setting when neoplastic cells are rare. On the other hand, one limitation of FCM analysis is the need for fresh samples. In this study, we provide evidence that a dedicated fixative allows the maintenance of an unaltered CD30 expression on the cell surface for up to 72 h.

Pleural fluid characteristics of patients with COVID-19 infection.

INTRODUCTION: Pleural effusions are known to occur in many cases of COVID-19. Data on typical characteristics of COVID-19-associated pleural effusions are limited. The goal of this project was to characterize the pleural fluid from patients with COVID-19. METHODS: We retrospectively collected electronic medical record data from adults hospitalized at a large metropolitan hospital system with COVID-19 infection who had a pleural effusion and a thoracentesis performed. We assessed pleural fluid characteristics and applied Light's criteria. RESULTS: We identified 128 effusions from 106 unique patients; 45.4% of the effusions had fluid/serum protein ratio greater than 0.5, 33.9% had fluid/serum lactate dehydrogenase (LDH) greater than 0.6, and 56.2% had fluid LDH greater than 2/3 of the serum upper limit of normal. Altogether, 68.5% of effusions met at least one of these three characteristics and therefore were exudative by Light's criteria. The white blood cell (WBC) differential was predominantly lymphocytic (mean 42.8%) or neutrophilic (mean 28.7%); monocytes (mean 12.7%) and eosinophils (mean 2.5%) were less common. CONCLUSION: We demonstrate that 68.5% of pleural effusions in patients with COVID-19 infection were exudative and hypothesize that COVID-19-associated pleural effusions are likely to be exudative with WBC differential more likely to be predominantly lymphocytic.

Biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz facilitated Cr(VI) reduction by shaping soil functional microbial communities.

Cr(VI) contamination is widely recognized as one of the major environmental hazards. To address the problem of remediation of soil Cr(VI) contamination and utilization of waste peanut shells, this study comprehensively investigated the effects of peanut shell-derived biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz on Cr(VI) reduction and microbial community succession in soil. This study confirmed that root exudate-loaded peanut shell biochar reduced soil pH while simultaneously increasing DOC, sulfide, and Fe(II) concentrations, thereby facilitating the reduction of Cr(VI), achieving a reduction efficiency of 81.8%. Based on XPS and SEM elemental mapping analyses, Cr(VI) reduction occurred concurrently with the Fe and S redox cycles. Furthermore, the microbial diversity, abundance of the functional genera (Geobacter, Arthrobacter, and Desulfococcus) and the metabolic functions associated with Cr(VI) reduction were enhanced by root exudate-loaded biochar. Root exudate-loaded biochar can promote both direct Cr(VI) reduction mediated by the Cr(VI)-reducing bacteria Arthrobacter, and indirect Cr(VI) reduction through Cr/S/Fe co-transformation mediated by the sulfate-reducing bacteria Desulfococcus and Fe(III)-reducing bacteria Geobacter. This study demonstrates the effectiveness of peanut shell biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz to promote soil Cr(VI) reduction, reveals the mechanism how root exudate-loaded biochar shapes functional microbial communities to facilitate Cr(VI) reduction, and proposes a viable strategy for Cr(VI) remediation and utilization of peanut shell.

Root exudates enhanced 6:2 FTOH defluorination, altered metabolite profiles and shifted soil microbiome dynamics.

6:2 Fluorotelomer alcohol (FTOH), one of per- and polyfluoroalkyl substances (PFAS), is widely used as a raw material in synthesizing surfactants and fluorinated polymers. However, little is known about the role of root exudates on 6:2 FTOH biodegradation in the rhizosphere. This study examined the effects of root exudates produced from dicot (Arabidopsis thaliana) and monocot (Brachypodium distachyon) grown under different nutrient conditions (nutrient-rich, sulfur-free, and potassium-free) on 6:2 FTOH biotransformation with or without bioaugmentating agent Rhodococcus jostii RHA1. All the exudates enhanced defluorination of 6:2 FTOH by glucose-grown RHA1. Amendment of dicot or monocot root exudates, regardless of the plant growth conditions, also enhanced 6:2 FTOH biotransformation in soil microcosms. Interestingly, high levels of humic-like substances in the root exudates are linked to high extents of 6:2 FTOH defluorination. Bioaugmenting strain RHA1 along with root exudates facilitated 6:2 FTOH transformation with a production of more diverse metabolites. Microbial community analysis revealed that Rhodococcus was predominant in all strain RHA1 spiked treatments. Different root exudates changed the soil microbiome dynamics. This study provided new insight into 6:2 FTOH biotransformation with different root exudates, suggesting that root exudates amendment and bioaugmentation are promising approaches to promote rhizoremediation for PFAS-contaminated soil.

Elucidating the significant roles of root exudates in organic pollutant biotransformation within the rhizosphere.

Biotransformation of organic pollutants is crucial for the dissipation of environmental pollutants. While the roles of microorganisms have been extensively studied, the significant contribution of various root exudates are still not very well understood. Through plant growth experiment, coupled with gas and liquid chromatography-mass spectrometry methods, this study examined the effect of the presence of M. sativa on microbial-associated biochemical transformation of petroleum hydrocarbons. The results of this study revealed that the concentration of exudates within the soil matrix is a function of proximity to root surfaces. Similarly, biodegradation was found to correlate with distance from roots, ranging from ≥ 90% within the rhizosphere to < 50% in bulk soil and unplanted control soil. Most importantly, for the first time in a study of an entire petroleum distillate, this study revealed a statistically significant negative correlation between root exudate concentration and residual total petroleum hydrocarbons. While not all the compounds that may influence biodegradation are derived from roots, the results of this study show that the presence of plant can significantly influence biodegradation of hydrocarbon pollutants through such root exudation as organic acids, amino acids, soluble sugars and terpenoids. Therefore, root exudates, including secondary metabolites, offer great prospects for biotechnological applications in the remediation of organic pollutants, including recalcitrant ones.

Comparison of quantification of intraretinal hard exudates between optical coherence tomography en face image versus fundus photography.

PURPOSE: To compare the quantification of intraretinal hard exudate (HE) using en face optical coherence tomography (OCT) and fundus photography. METHODS: Consecutive en face images and corresponding fundus photographs from 13 eyes of 10 patients with macular edema associated with diabetic retinopathy or Coats' disease were analyzed using the machine-learning-based image analysis tool, "ilastik." RESULTS: The overall measured HE area was greater with en face images than with fundus photos (en face: 0.49 ± 0.35 mm2 vs. fundus photo: 0.34 ± 0.34 mm2, P < 0.001). However, there was an excellent correlation between the two measurements (intraclass correlation coefficient [ICC] = 0.844). There was a negative correlation between HE area and central macular thickness (CMT) (r = -0.292, P = 0.001). However, HE area showed a positive correlation with CMT in the previous several months, especially in eyes treated with anti-vascular endothelial growth factor (VEGF) therapy (CMT 3 months before: r = 0.349, P = 0.001; CMT 4 months before: r = 0.287, P = 0.012). CONCLUSION: Intraretinal HE can be reliably quantified from either en face OCT images or fundus photography with the aid of an interactive machine learning-based image analysis tool. HE area changes lagged several months behind CMT changes, especially in eyes treated with anti-VEGF injections.

Harnessing root exudates for plant microbiome engineering and stress resistance in plants.

A wide range of abiotic and biotic stresses adversely affect plant's growth and production. Under stress, one of the main responses of plants is the modulation of exudates excreted in the rhizosphere, which consequently leads to alterations in the resident microbiota. Thus, the exudates discharged into the rhizospheric environment play a preponderant role in the association and formation of plant-microbe interactions. In this review, we aimed to provide a synthesis of the latest and most pertinent literature on the diverse biochemical and structural compositions of plant root exudates. Also, this work investigates into their multifaceted role in microbial nutrition and intricate signaling processes within the rhizosphere, which includes quorum-sensing molecules. Specifically, it explores the contributions of low molecular weight compounds, such as carbohydrates, phenolics, organic acids, amino acids, and secondary metabolites, as well as the significance of high molecular weight compounds, including proteins and polysaccharides. It also discusses the state-of-the-art omics strategies that unveil the vital role of root exudates in plant-microbiome interactions, including defense against pathogens like nematodes and fungi. We propose multiple challenges and perspectives, including exploiting plant root exudates for host-mediated microbiome engineering. In this discourse, root exudates and their derived interactions with the rhizospheric microbiota should receive greater attention due to their positive influence on plant health and stress mitigation.

Value of human epididymis secretory protein 4 in differentiating malignant from benign pleural effusion: an analysis of two cohorts.

BACKGROUND: Lung cancer is the most common cause of malignant pleural effusion (MPE). Serum human epididymis secretory protein 4 (HE4) is a useful diagnostic marker for lung cancer. OBJECTIVE: This study aimed to evaluate the diagnostic accuracy of pleural fluid HE4 for MPE. DESIGN: A prospective, double-blind diagnostic test accuracy study. METHODS: Patients with undiagnosed pleural effusion were enrolled in two cohorts (Hohhot and Changshu). Electrochemiluminescence immunoassay was used to detect pleural fluid HE4. The diagnostic accuracy of HE4 was evaluated by a receiver operating characteristic (ROC) curve, and the net benefit of HE4 was assessed by a decision curve analysis (DCA). RESULTS: A total of 66 MPEs and 86 benign pleural effusions (BPEs) were enrolled in the Hohhot cohort. In the Changshu cohort, 26 MPEs and 32 BPEs were enrolled. In both cohorts, MPEs had significantly higher pleural fluid HE4 than BPEs. The area under the ROC curve (AUC) of HE4 was 0.73 (95% CI: 0.64-0.81) in the Hohhot cohort and 0.79 (95% CI: 0.67-0.91) in the Changshu cohort. At a threshold of 1300 pmol/L, HE4 had sensitivities of 0.44 (95% CI: 0.33-0.56) in the Hohhot cohort and 0.54 (95% CI: 0.35-0.73) in the Changshu cohort. The corresponding specificities were 0.90 (95% CI: 0.83-0.95) in the Hohhot cohort and 0.94 (95% CI: 0.84-1.00) in the Changshu cohort. In subgroup analyses, HE4 had an AUC (95% CI) of 0.78 (0.71-0.85) in exudates and an AUC of 0.69 (0.57-0.81) in patients with negative effusion cytology. The DCA revealed that HE4 determination had a net benefit in both cohorts. CONCLUSION: Pleural fluid HE4 has moderate diagnostic accuracy for MPE and has net benefit in pleural effusion patients with unknown etiology.

Phosphorus deficiency alters root length, acid phosphatase activity, organic acids, and metabolites in root exudates of soybean cultivars.

Phosphorus (P) deficiency alters the root morphological and physiological traits of plants. This study investigates how soybean cultivars with varying low-P tolerance values respond to different P levels in hydroponic culture by assessing alterations in root length, acid phosphatase activity, organic acid exudation, and metabolites in root exudates. Three low-P-tolerant cultivars ('Maetsue,' 'Kurotome,' and 'Fukuyutaka') and three low-P-sensitive cultivars ('Ihhon,' 'Chizuka,' and 'Komuta') were grown under 0 (P0) and 258 µM P (P8) for 7 and 14 days after transplantation (DAT). Low-P-tolerant cultivars increased root length by 31% and 119%, which was lower than the 62% and 144% increases in sensitive cultivars under P0 compared to P8 at 7 and 14 DAT, respectively. Acid phosphatase activity in low-P-tolerant cultivars exceeded that in sensitive cultivars by 5.2-fold and 2.0-fold at 7 and 14 DAT. Root exudates from each cultivar revealed 177 metabolites, with higher organic acid exudation in low-P-tolerant than sensitive cultivars under P0. Low-P-tolerant cultivars increased concentrations of specific metabolites (oxalate, GABA, quinate, citrate, AMP, 4-pyridoxate, and CMP), distinguishing them from low-P-sensitive cultivars under P0. The top five metabolomic pathways (purine metabolism, arginine and proline metabolism, TCA cycle, glyoxylate and dicarboxylate metabolism, alanine, aspartate, and glutamate metabolism) were more pronounced in low-P-tolerant cultivars at 14 DAT. These findings indicate that increasing root length was not an adaptation strategy under P deficiency; instead, tolerant cultivars exhibit enhanced root physiological traits, including increased acid phosphatase activity, organic acid exudation, specific metabolite release, and accelerated metabolic pathways under P deficiency.

Pleural Effusion: Diagnostic Approach in Adults.

Pleural effusion affects 1.5 million patients in the United States each year. New effusions require expedited investigation because treatments range from common medical therapies to invasive surgical procedures. The leading causes of pleural effusion in adults are heart failure, infection, malignancy, and pulmonary embolism. The patient's history and physical examination should guide evaluation. Small bilateral effusions in patients with decompensated heart failure, cirrhosis, or kidney failure are likely transudative and do not require diagnostic thoracentesis. In contrast, pleural effusion in the setting of pneumonia (parapneumonic effusion) may require additional testing. Multiple guidelines recommend early use of point-of-care ultrasound in addition to chest radiography to evaluate the pleural space. Chest radiography is helpful in determining laterality and detecting moderate to large pleural effusions, whereas ultrasonography can detect small effusions and features that could indicate complicated effusion (i.e., infection of the pleural space) and malignancy. Point-of-care ultrasound should also guide thoracentesis because it reduces complications. Computed tomography of the chest can exclude other causes of dyspnea and suggest complicated parapneumonic or malignant effusion. When diagnostic thoracentesis is indicated, Light's criteria can help differentiate exudates from transudates. Pleural aspirate should routinely be evaluated using Gram stain, cell count with differential, culture, cytology, protein, l-lactate dehydrogenase, and pH levels. Additional assessments should be individualized, such as tuberculosis testing in high-prevalence regions. Parapneumonic effusions are the most common cause of exudates. A pH level less than 7.2 is indicative of complicated parapneumonic effusion and warrants prompt consultation for catheter or chest tube drainage, possible tissue plasminogen activator/deoxyribonuclease therapy, or thoracoscopy. Malignant effusions are another common cause of exudative effusions, with recurrent effusions having a poor prognosis.

Metabolomics reveals the impact of nitrogen combined with the zinc supply on zinc availability in calcareous soil via root exudates of winter wheat (Triticum aestivum).

A possible mechanism for the improved availability of zinc (Zn) in soil by combining nitrogen (N) with Zn supply was investigated based on the root exudates of winter wheat. N, Zn supply as well as their combination significantly regulated nine root exudates in winter wheat; in which, the secretion of cis-aconitic acid involving in the TCA cycle, C5-branched dibasic acid metabolism, glyoxylate and dicarboxylate metabolism and 2-oxocarboxylic acid metabolism was upregulated by N, Zn supply as well as their combination. N-Zn combination induced the activities of citrate synthase and cis-aconitase in roots and shoots of winter wheat thus to increase the concentrations of citric and aconitic acid; the decrease of isocitric acid concentrations in shoots indicated the inhibited conversion of aconitic acid to isocitric acid by N-Zn combination. It revealed a possible reason for the enhanced secretion of cis-aconitic acid by N-Zn combination. Exogenous addition of 10 µ plant-1 cis-aconitate significantly increased available Zn concentrations in soil and Zn concentrations in winter wheat under N-Zn combination. Thus, the N-Zn combination regulated the metabolism of cis-aconitic acid in winter wheat, thus enhancing the secretion of cis-aconitic acid to increase the bioavailability of Zn in soil.

Conditional diagnostic accuracy according to inflammation status and age for diagnosing tuberculous effusion.

BACKGROUND: Tuberculous effusion varies from lymphocyte-dominant to neutrophilic effusion according to inflammation status. The criteria of adenosine deaminase (ADA) and lymphocyte/neutrophil (L/N) ratio have yet not been evaluated across different disease conditions. METHODS: Patients who conducted pleural fluid analysis from 2009 to 2019 at Asan Medical Center were included. Criteria (ADA of 50 and L/N ratio of 0.75) were evaluated by quantile subgroups according to age, C-reactive protein (CRP), white blood cell (WBC), and lactate dehydrogenase (LD) by the Monte Carlo simulation method to diagnose tuberculosis. The model for the ADA and L/N ratio was evaluated by AUROC. RESULTS: Among the 2,918 reviewed cases, 2034 were included with 229 (11.26%) tuberculosis cases. The mean baseline ADA AUROC was 0.88 across all patients. Increased CRP and WBC showed high proportions of neutrophilic tuberculous effusion, with low sensitivity of approximately 45% and 33% in the fifth WBC and CRP groups, respectively. The AUROC of the models decreased with the increase in WBC and CRP groups (ADA model: 0.69 [the top quantile WBC group], 0.74 [the top quantile CRP group]). The AUROC of the models did not show a trend according to the increase in LD and age. CONCLUSION: Inflammatory status affects the diagnostic metrics for tuberculous effusion due to the progression of tuberculous effusion. Clinicians should consider the low accuracy of tuberculous effusion criteria in high-inflammatory conditions when diagnosing tuberculosis.

Simulated phytoremediation by root exudates of Sudan grass of soil organochlorine pesticides: impact on the rhizosphere microbial community.

The present work aims to study the efficiency of root exudates of Sudan grass on the degradation of organochlorine pesticides (OCPs) and the consequent impact on the microbial and ecological characteristics of the soil, including population composition, quantity dynamics, and community structure. Pot experiments were carried out to study the effect of root exudates on the degradation of OCPs at initial concentrations ranging from 66.67 to 343.61 mg/kg. In addition, the influence of root exudates on the rhizosphere microbial growth and their community structure was studied by monitoring the microbial biomass carbon, microbial biomass nitrogen, and phospholipid fatty acids (PLFAs) in the soils. In the range of OCP content (66.67 ~ 343.61 mg/kg), the soil-microbial system mediated by root exudates significantly promoted the removal of OCP pollutants. The removal rate of OCPs in the rhizosphere soil (TR2) was as high as 79.32%, 36.86% higher than that in the OCP-contaminated group (TR1) and 60.63% higher than that in the sterilized treatment group (CK). Under the same treatment conditions (pollution level and additive dose), the enhanced removal rate of HCHs, toxaphene, HCB, aldrin, and γ-chlordane by root exudates was much higher than the total amount of OCPs, while the extent of enhanced dissipation of DDTs, mirex, endosulfanI, dieldrin, and heptachlor epoxide was always lower than that in the corresponding soils. During the experiment, the phospholipid fatty acid content of bacteria was dominant, followed by that of fungi, and their variation trend was consistent with the degradation characteristics of OCPs in soil. Root exudates of Sudan grass might change the rhizosphere bacterial and fungal community structure during the process of phytoremediation, leading to enhanced OCP degradation.

Vitislactone, a non-canonical strigolactone exudated by grapevine rootstocks in response to nitrogen starvation.

Strigolactones are compounds produced by plant roots in response to nutrient deficiency, acting both as local and systemic signals to control development and nutrition. Strigolactones are exuded in the rhizosphere to positively influence interactions with beneficial microbes. LC-MS/MS analysis shows that two genetically distinct grapevine rootstocks exudate one or two non-canonical strigolactones when subjected to low nitrogen conditions. Gene expression profiles and orobanche seed germination assays confirm that the biosynthesis and exudation of non-canonical compounds is the preferred pathway. The first compound, corresponding to heliolactone or 6-epi-heliolactone, is only exuded by the rootstock showing lower shoot branching and a higher level of mycorrhization with arbuscular mycorrhizal fungi. The structure of the second compound exuded by both rootstocks was identified by NMR and LC-MS/MS analysis. It is a non-canonical strigolactone, which has never been identified in another species. This first identification of a natural compound with the potential to stimulate beneficial root-microbe interactions in grapevines opens new perspectives in viticulture.

Collection of Alfalfa Root Exudates to Study the Impact of Di(2-ethylhexyl) Phthalate on Metabolite Production.

Root exudates are the main media of information communication and energy transfer between plant roots and the surrounding environment. The change in secretion of root exudates is usually an external detoxification strategy for plants under stress conditions. This protocol aims to introduce general guidelines for the collection of alfalfa root exudates to study the impact of di(2-ethylhexyl) phthalate (DEHP) on metabolite production. First, alfalfa seedlings are grown under DEHP stress in a hydroponic culture experiment. Second, the plants are transferred to centrifuge tubes containing 50 mL of sterilized ultrapure water for 6 h to collect root exudates. The solutions are then freeze-dried in a vacuum freeze dryer. The frozen samples are extracted and derivatized with bis(trimethylsilyl)) trifluoroacetamide (BSTFA) reagent. Subsequently, the derivatized extracts are measured using a gas chromatograph system coupled with a time-of-flight mass spectrometer (GC-TOF-MS). The acquired metabolite data are then analyzed based on bioinformatic methods. Differential metabolites and significantly changed metabolism pathways should be deeply explored to reveal the impact of DEHP on alfalfa in view of root exudates.

A practical approach to pseudoexudative pleural effusions.

Light's criteria falsely label a significant number of effusions as exudates. Such exudative effusions with transudative etiologies are referred to as "pseduoexudates". In this review, we discuss a practical approach to correctly classify an effusion that may be a pseudoexudate. A PubMed search yielded 1996 manuscripts between 1990 and 2022. Abstracts were screened and 29 relevant studies were included in this review article. Common etiologies for pseudoexudates include diuretic therapy, traumatic pleural taps, and coronary artery bypass grafting. Here, we explore alternative diagnostic criteria. Concordant exudates (CE), defined as effusions where proteins in pleural fluid/serum (PF/SPr) > 0.5 and pleural fluid LDH level of >160 IU/L (>2/3 upper limit of normal) confer higher predictive value to the Light's criteria. Serum-pleural effusion albumin gradient (SPAG) > 1.2 g/dL and serum-pleural effusion protein gradient (SPPG) > 3.1 g/dL together yielded a sensitivity of 100% in heart failure and a sensitivity of 99% in hepatic hydrothorax whe n identifying pseudoexudates (Bielsa et al., 2012) [5]. Pleural fluid N-Terminal Pro Brain Natriuretic Peptide (NTPBNP) offered a specificity and sensitivity of 99% in identifying pseudoexudates when using a cut-off of >1714 pg/mL (Han et al., 2008) [24]. However, its utility remains questionable. Additionally, we also looked at pleural fluid cholesterol and imaging modalities such as ultrasound and CT scan to measure pleural thickness and nodularity. Finally, the diagnostic algorithm we suggest involves using SPAG >1.2 g/dL and SPPG >3.1 g/dL in effusions classified as exudates when there is a strong clinical suspicion for pseudoexudates.

Development of a root exudate collection protocol for metabolomics analysis using Nuclear Magnetic Resonance.

Large amounts of root exudates are released by plant roots into the soil. Due to their importance in regulating the rhizosphere properties, it is necessary to unravel the precise composition and function of exudates at the root-soil interface. However, obtaining root exudates without inducing artefacts is a difficult task. To analyse the low molecular weight molecules secreted by pea roots, a protocol of root exudate collection was developed to perform a metabolomics analysis using Nuclear Magnetic Resonance (NMR). To date a few NMR studies are dedicated to root exudates. Plant culture, exudates collection and sample preparation methods had thus to be adapted to the NMR approach. Here, pea seedlings were hydroponically grown. The obtained NMR fingerprints show that osmotic stress increases the quantity of the exudates but not their diversity. We therefore selected a protocol reducing the harvest time and using an ionic solvent and applied it to the analysis of faba bean exudates. NMR analysis of the metabolic profiles allowed to discriminate between pea and faba bean according to their exudate composition. This protocol is therefore very promising for studying the composition of root exudates from different plant species as well as their evolution in response to different environmental conditions or pathophysiological events.

Plant growth strategy determines the magnitude and direction of drought-induced changes in root exudates in subtropical forests.

Root exudates are an important pathway for plant-microbial interactions and are highly sensitive to climate change. However, how extreme drought affects root exudates and the main components, as well as species-specific differences in response magnitude and direction, are poorly understood. In this study, root exudation rates of total carbon (C) and its components (e.g., sugar, organic acid, and amino acid) were measured under the control and extreme drought treatments (i.e., 70% throughfall reduction) by in situ collection of four tree species with different growth rates in a subtropical forest. We also quantified soil properties, root morphological traits, and mycorrhizal infection rates to examine the driving factors underlying variations in root exudation. Our results showed that extreme drought significantly decreased root exudation rates of total C, sugar, and amino acid by 17.8%, 30.8%, and 35.0%, respectively, but increased root exudation rate of organic acid by 38.6%, which were largely associated with drought-induced changes in tree growth rates, root morphological traits, and mycorrhizal infection rates. Specifically, trees with relatively high growth rates were more responsive to drought for root exudation rates compared with those with relatively low growth rates, which were closely related to root morphological traits and mycorrhizal infection rates. These findings highlight the importance of plant growth strategy in mediating drought-induced changes in root exudation rates. The coordinations among root exudation rates, root morphological traits, and mycorrhizal symbioses in response to drought could be incorporated into land surface models to improve the prediction of climate change impacts on rhizosphere C dynamics in forest ecosystems.

Implications of Pleural Fluid Composition in Persistent Pleural Effusion following Orthotopic Liver Transplant.

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (ExudLight) by Light's criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (ExudLDH) or elevated protein (ExudProt). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were ExudLight. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While ExudLight and ExudProt showed no association with outcomes, ExudLDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light's criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.