Pleural fluid biomarkers: a narrative review.

Background and Objective: Pleural fluid is a source from which various biomarkers can be obtained and measured to facilitate the management and prognostication of various conditions. This narrative review aims to summarise a few selected applications of pleural fluid biomarker analysis based on the latest literature. Methods: A literature search for articles published in English regarding human subjects from the period January 2000 to December 2023 was performed through PubMed. Publications considered by the authors to be relevant were included in this review, with additional references added based on the authors' judgement. This review considered both prospective and retrospective cohort studies analysing the clinical value of a range of pleural fluid biomarkers. Key Content and Findings: The biomarkers selected in this narrative review have either established clinical applicability or promising initial results which require further research. Pleural fluid adenosine deaminase, mesothelin and N-terminal pro-B-type natriuretic peptide can optimize the diagnosis of tuberculous pleuritis, malignant mesothelioma and heart failure-related pleural effusion respectively. The detection rate for epidermal growth factor receptor mutations for lung cancer is higher in the pleural fluid than in the pleural tissue or plasma. Suitable targeted therapy in patients with detectable mutations can offer survival benefits. The pleural fluid neutrophil-lymphocyte ratio, soluble urokinase plasminogen activator receptor and plasminogen activator inhibitor 1 carry prognostic implications and can potentially guide subsequent treatment decisions. These biomarkers used individually, or in conjunction with other clinical parameters, should only be utilised in pre-defined, appropriate clinical conditions to maximize their clinical value. Conclusions: A great variety of different biomarkers are available for analysis in pleural fluid. Further research and development are necessary to widen the spectrum and enhance the clinical utility of pleural fluid biomarkers. Comparison with the diagnostic utilities of serum biomarkers and other investigation parameters, such as radiological findings, could be considered when evaluating the performance of pleural fluid biomarkers.

The gastrointestinal microbiome, small bowel bacterial overgrowth, and microbiome modulators in cystic fibrosis.

People with cystic fibrosis (pwCF) have an altered gastrointestinal microbiome. These individuals also demonstrate propensity toward developing small intestinal bacterial overgrowth (SIBO). The dysbiosis present has intestinal and extraintestinal implications, including potential links with the higher rates of gastrointestinal malignancies described in CF. Given these implications, there is growing interest in therapeutic options for microbiome modulation. Alternative therapies, including probiotics and prebiotics, and current CF transmembrane conductance regulator gene modulators are promising interventions for ameliorating gut microbiome dysfunction in pwCF. This article will characterize and discuss the current state of knowledge and expert opinions on gut dysbiosis and SIBO in the context of CF, before reviewing the current evidence supporting gut microbial modulating therapies in CF.

Coronary and Systemic Vasodilator Responsiveness of Patients Receiving Conventional Intermittent or Nocturnal Hemodialysis.

BACKGROUND: Nocturnal hemodialysis (nHD) restores the attenuated brachial artery vasodilator responsiveness of patients receiving conventional intermittent hemodialysis (iHD). Its impact on coronary vasodilatation is unknown. METHODS: We evaluated 25 patients on hemodialysis who fulfilled transplant criteria: 15 on iHD (4-hour sessions, 3 d/wk) and 10 on nHD (≈40 h/wk over 8-10-hour sessions) plus 6 control participants. Following diagnostic angiography, left anterior descending (LAD) coronary flow reserve and mean luminal diameter were quantified at baseline and during sequential intracoronary administration of adenosine (infusion and bolus), nitroglycerin (bolus), acetylcholine (infusion), acetylcholine coinfused with vitamin C, and, finally, sublingual nitroglycerin. RESULTS: Coronary flow reserve in those receiving nHD was augmented relative to iHD (3.28±0.26 versus 2.17±0.12 [mean±SEM]; P<0.03) but attenuated, relative to controls (4.80±0.63; P=0.011). Luminal dilatations induced by intracoronary adenosine and nitroglycerin were similar in nHD and controls but blunted in the iHD cohort (P<0.05 versus both). ACh elicited vasodilatation in controls but constriction in both dialysis groups (both P<0.05, versus control); vitamin C coinfusion had no effect. Sublingual nitroglycerin increased mid-left anterior descending diameter and reduced mean arterial pressure in controls (+15.2±2.68%; -16.00±1.60%) and in nHD recipients (+14.78±5.46%; -15.82±1.32%); iHD responses were markedly attenuated (+1.9±0.86%; -5.89±1.41%; P<0.05, all comparisons). CONCLUSIONS: Coronary and systemic vasodilator responsiveness to both adenosine and nitroglycerin is augmented in patients receiving nHD relative to those receiving iHD, whereas vasoconstrictor responsiveness to acetylcholine does not differ. By improving coronary conduit and microvascular function, nHD may reduce the cardiovascular risk of patients on dialysis.

Integrated home dialysis model: facilitating home-to-home transition.

Peritoneal dialysis (PD) and home hemodialysis (HHD) are the two home dialysis modalities offered to patients. They promote patient autonomy, enhance independence, and are generally associated with better quality of life compared to facility hemodialysis. PD offers some advantages (enhanced flexibility, ability to travel, preservation of residual kidney function, and vascular access sites) but few patients remain on PD indefinitely due to peritonitis and other complications. By contrast, HHD incurs longer and more intensive training combined with increased upfront health costs compared to PD, but is easier to sustain in the long term. As a result, the integrated home dialysis model was proposed to combine the advantages of both home-based dialysis modalities. In this paradigm, patients are encouraged to initiate dialysis on PD and transfer to HHD after PD termination. Available evidence demonstrates the feasibility and safety of this approach and some observational studies have shown that patients who undergo the PD-to-HHD transition have clinical outcomes comparable to patients who initiate dialysis directly on HHD. Nevertheless, the prevalence of PD-to-HHD transfers remains low, reflecting the multiple barriers that prevent the full uptake of home-to-home transitions, notably a lack of awareness about the model, home-care "burnout," clinical inertia after a transfer to facility HD, suboptimal integration of PD and HHD centers, and insufficient funding for home dialysis programs. In this review, we will examine the conceptual advantages and disadvantages of integrated home dialysis, present the evidence that underlies it, identify challenges that prevent its success and finally, propose solutions to increase its adoption.

Antiarrhythmic Mechanisms of Epidural Blockade After Myocardial Infarction.

BACKGROUND: Thoracic epidural anesthesia (TEA) has been shown to reduce the burden of ventricular tachycardia in small case series of patients with refractory ventricular tachyarrhythmias and cardiomyopathy. However, its electrophysiological and autonomic effects in diseased hearts remain unclear, and its use after myocardial infarction is limited by concerns for potential right ventricular dysfunction. METHODS: Myocardial infarction was created in Yorkshire pigs (N=22) by left anterior descending coronary artery occlusion. Approximately, six weeks after myocardial infarction, an epidural catheter was placed at the C7-T1 vertebral level for injection of 2% lidocaine. Right and left ventricular hemodynamics were recorded using Millar pressure-conductance catheters, and ventricular activation recovery intervals (ARIs), a surrogate of action potential durations, by a 56-electrode sock and 64-electrode basket catheter. Hemodynamics and ARIs, baroreflex sensitivity and intrinsic cardiac neural activity, and ventricular effective refractory periods and slope of restitution (Smax) were assessed before and after TEA. Ventricular tachyarrhythmia inducibility was assessed by programmed electrical stimulation. RESULTS: TEA reduced inducibility of ventricular tachyarrhythmias by 70%. TEA did not affect right ventricular-systolic pressure or contractility, although left ventricular-systolic pressure and contractility decreased modestly. Global and regional ventricular ARIs increased, including in scar and border zone regions post-TEA. TEA reduced ARI dispersion specifically in border zone regions. Ventricular effective refractory periods prolonged significantly at critical sites of arrhythmogenesis, and Smax was reduced. Interestingly, TEA significantly improved cardiac vagal function, as measured by both baroreflex sensitivity and intrinsic cardiac neural activity. CONCLUSIONS: TEA does not compromise right ventricular function in infarcted hearts. Its antiarrhythmic mechanisms are mediated by increases in ventricular effective refractory period and ARIs, decreases in Smax, and reductions in border zone electrophysiological heterogeneities. TEA improves parasympathetic function, which may independently underlie some of its observed antiarrhythmic mechanisms. This study provides novel insights into the antiarrhythmic mechanisms of TEA while highlighting its applicability to the clinical setting.

The effect of implementing a dialysis start unit on modality decision among patients with unplanned start kidney replacement therapy.

INTRODUCTION: Many individuals start dialysis in an acute setting with suboptimal pre-dialysis education. These individuals are often treated with central venous catheter insertion and initiation of in-center hemodialysis and only a minority will transfer to a home-based therapy. The dialysis start unit is a program performing in-center hemodialysis in a separate space while providing support and education on chronic kidney disease and treatment options in the initial weeks of kidney replacement therapy. We aimed to assess the uptake of home dialysis therapies between 2013 and 2021 among patients who started acute inpatient hemodialysis at University Health Network, Toronto and underwent dialysis at the dialysis start unit. METHODS: This is a retrospective observational cohort study based on prospectively collected data. Patients' demographics were obtained from electronic charts. In the dialysis start unit, all patients received dialysis modality education by a nurse educator, dedicated home dialysis nurses, and the allied health care team. FINDINGS: During 2013-2021, 122 patients were dialyzed in the dialysis start unit and included in the study. Among those patients, 68 patients ultimately chose home dialysis (57 peritoneal dialysis and 11 home hemodialysis). Fifty-four patients continued in-center hemodialysis. Patients adopting home dialysis were less likely to have diabetes and hypertension as the etiology of kidney failure and more likely to have glomerulonephritis or vasculitis. DISCUSSION: Dialysis modality education is implementable in advanced chronic kidney disease. Individualized education and care after unplanned start dialysis can potentially enhance home dialysis choice and utilization.

Intraoperative hemodialysis with supra- and infradiaphragmatic catheters for liver transplantation.

PURPOSE: The benefits of intraoperative dialysis during orthotopic liver transplantation remain controversial. In patients with anuric renal failure and portopulmonary hypertension, maintaining venous return during caval clamping and unclamping along with minimizing fluid overload is critical to avoiding right ventricular strain and failure. CLINICAL FEATURES: We present the case of a 54-yr-old female who underwent orthotopic liver transplantation for alcohol-related liver disease with acute decompensation including severe hepatorenal syndrome (anuric requiring dialysis), probable hepatopulmonary syndrome, moderate pulmonary hypertension (right ventricular systolic pressure, 44 mm Hg), hepatic encephalopathy (grade 2), and esophageal varices. Prior to incision, pulmonary arterial pressures were 48/28 (mean, 35) mm Hg with a central venous pressure of 30 mm Hg, cardiac output of 7.4 L·min-1, and pulmonary vascular resistance of 98 dynes·sec·cm-5. In the context of right ventricular strain and volume overload observed on transthoracic echocardiography, we inserted an additional dialysis catheter into the right femoral vein. We initiated dialysis using the two catheters as a circuit (femoral line to the dialysis machine; blood was reinjected via the subclavian line) acting as a limited venovenous bypass, allowing right ventricular offloading and hemodialysis throughout the case. We removed 4.5 L via hemodialysis during the surgery, while avoiding acidosis, hyperkalemia, and sodium shifts. The patient tolerated reperfusion adequately despite pre-existing right ventricular dilation and dysfunction. CONCLUSION: We report on the use two hemodialysis catheters in a patient undergoing orthotopic liver transplantation as a circuit for simultaneous anuric hepatorenal syndrome and moderate pulmonary hypertension with right ventricular dilation and dysfunction. We believe this technique was instrumental in the patient's successful transplant.

RéSUMé: OBJECTIF: Les avantages de la dialyse peropératoire pendant une transplantation hépatique orthotopique demeurent controversés. Chez la patientèle atteinte d'insuffisance rénale anurique et d'hypertension portopulmonaire, il est essentiel de maintenir le retour veineux pendant le clampage et le déclampage de la veine cave ainsi que de minimiser la surcharge hydrique, afin d'éviter la déformation et l'insuffisance ventriculaires droites. CARACTéRISTIQUES CLINIQUES : Nous présentons le cas d'une femme de 54 ans qui a bénéficié d'une transplantation hépatique orthotopique pour une maladie hépatique liée à l'alcool avec une décompensation aiguë comprenant un syndrome hépatorénal sévère (anurie nécessitant une dialyse), un syndrome hépatopulmonaire probable, une hypertension pulmonaire modérée (pression systolique ventriculaire droite, 44 mm Hg), une encéphalopathie hépatique (grade 2) et des varices œsophagiennes. Avant l'incision, les pressions artérielles pulmonaires étaient de 48/28 (moyenne, 35) mm Hg avec une pression veineuse centrale de 30 mm Hg, un débit cardiaque de 7,4 L·min−1 et une résistance vasculaire pulmonaire de 98 dynes·sec·cm−5. Dans le contexte de la déformation ventriculaire et de la surcharge volémique droites observées à l'échocardiographie transthoracique, nous avons inséré un cathéter de dialyse supplémentaire dans la veine fémorale droite. Nous avons amorcé la dialyse en créant un circuit avec les deux cathéters (ligne fémorale en direction de l'appareil de dialyse; sang réinjecté via la ligne sous-clavière) agissant comme un pontage veino-veineux limité, permettant la décharge du ventricule droit et l'hémodialyse tout au long du cas. Nous avons retiré 4,5 L par hémodialyse pendant la chirurgie, tout en évitant l'acidose, l'hyperkaliémie et les changements en sodium plasmatique. La patiente a toléré la reperfusion de manière adéquate malgré la dilatation et le dysfonctionnement préexistants du ventricule droit. CONCLUSION: Nous rapportons l'utilisation de deux cathéters d'hémodialyse pour créer un circuit chez une patiente bénéficiant d'une transplantation hépatique orthotopique pour le traitement d'un syndrome hépatorénal anurique simultané à une hypertension pulmonaire modérée avec dilatation et dysfonctionnement du ventricule droit. Nous pensons que cette technique a joué un rôle déterminant dans la réussite de la greffe chez la patiente.

Slow Hot-Exciton Cooling and Enhanced Interparticle Excitonic Coupling in HgTe Quantum Dots.

Rapid hot-carrier/exciton cooling constitutes a major loss channel for photovoltaic efficiency. How to decelerate the hot-carrier/exciton relaxation remains a crux for achieving high-performance photovoltaic devices. Here, we demonstrate slow hot-exciton cooling that can be extended to hundreds of picoseconds in colloidal HgTe quantum dots (QDs). The energy loss rate is 1 order of magnitude smaller than bulk inorganic semiconductors, mediated by phonon bottleneck and interband biexciton Auger recombination (BAR) effects, which are both augmented at reduced QD sizes. The two effects are competitive with the emergence of multiple exciton generation. Intriguingly, BAR dominates even under low excitation fluences with a decrease in interparticle distance. Both experimental evidence and numerical evidence reveal that such efficient BAR derives from the tunneling-mediated interparticle excitonic coupling induced by wave function overlap between neighboring HgTe QDs in films. Thus, our study unveils the potential for realizing efficient hot-carrier/exciton solar cells based on HgTe QDs. Fundamentally, we reveal that the delocalized nature of quantum-confined wave function intensifies BAR. The interparticle excitonic coupling may cast light on the development of next-generation photoelectronic materials, which can retain the size-tunable confinement of colloidal semiconductor QDs while simultaneously maintaining high mobilities and conductivities typical for bulk semiconductor materials.

Digital Image Comparison of Cellular Yield in Bronchial Brushing: Pre- and Post-Biopsy Lavage Cytology.

INTRODUCTION: Bronchoscopy is a useful diagnostic tool capable of performing core biopsy, forceps biopsy, bronchoalveolar lavage, and bronchial brushing. This study compares the cellularity of bronchial cytology including pre- and post-biopsy lavage by digital image analysis, aiming to increase diagnostic and tumor yield by optimizing the sequence and combination of bronchial biopsy and cytology. METHODS: Alveolar macrophage, bronchial epithelium, and tumor cell cellularity from liquid-based cytology preparations of bronchial brushing and pre-biopsy and post-biopsy bronchoalveolar lavage were annotated on digitized whole-slide images and compared. Secondary analysis on the relationship of tumor cell and non-lesional cell yield was performed. RESULTS: Overall, 118 cytology specimens from 43 patients were retrieved in total. Bronchial epithelium count was higher in pre-biopsy than post-biopsy lavage (p < 0.01) but not for alveolar macrophages nor tumor cell (p > 0.05). Tumor cell count was higher for bronchial brushing cytology samples than lavage (p = 0.018). The alveolar macrophage count was higher in post-biopsy lavage than bronchial brushing (p = 0.033); otherwise, brushing showed consistently higher bronchial epithelium and tumor cell counts. There were 33 false negative (tumor cell absent) specimens, and the combination of bronchial brushing and pre-biopsy lavage yielded the lowest false negative cases. Correlation between bronchial epithelium and alveolar macrophage counts with tumor cell count was weak (correlation coefficient = -0.168-0.203) except for post-biopsy lavage (correlation coefficient = 0.412-0.479, p < 0.05). CONCLUSION: Bronchial brushing yields a greater amount of tumor cell than lavage, and timing lavage before or after core biopsy does not affect tumor cell yield. Combining bronchial brushing and pre-biopsy lavage results in the lowest false negative rate.

Vascular Access Considerations in Home Hemodialysis.

There is a global interest in expanding home dialysis utilization among patients with ESKD. Home hemodialysis (HHD) is an appealing KRT option for this population because of its multiple clinical and quality of life benefits. Central to successful HHD is the establishment and maintenance of a functioning vascular access that serves as a patient's lifeline while on therapy. While the selection of a vascular access type is influenced by individual patient circumstances, the arteriovenous fistula is generally the preferred access method. Training patients to use their dialysis access requires attention to safety, risk management, and monitoring for complications to minimize adverse events and technique failure. Policies incorporating systematic frameworks for quality improvement and assurance, in conjunction with the measurement of metrics relating to vascular access, are tools that should be used by HHD programs to enhance the value of care delivered. In this perspective, we aim to describe what is currently known about the various vascular access options in HHD and to elucidate what needs to be taken into consideration in the selection and care of this access.

Thoracic epidural blockade after myocardial infarction benefits from anti-arrhythmic pathways mediated in part by parasympathetic modulation.

Background: Thoracic epidural anesthesia (TEA) has been shown to reduce the burden of ventricular tachyarrhythmias (VT) in small case-series of patients with refractory VT and cardiomyopathy. However, its electrophysiological and autonomic effects in diseased hearts remain unclear and its use after myocardial infarction (MI) is limited by concerns for potential RV dysfunction. Methods: MI was created in Yorkshire pigs ( N =22) by LAD occlusion. Six weeks post-MI, an epidural catheter was placed at the C7-T1 vertebral level for injection of 2% lidocaine. RV and LV hemodynamics were recorded using Millar pressure-conductance catheters, and ventricular activation-recovery intervals (ARIs), a surrogate of action potential durations, by a 56-electrode sock and 64-electrode basket catheter. Hemodynamics and ARIs, baroreflex sensitivity (BRS) and intrinsic cardiac neural activity, and ventricular effective refractory periods (ERP) and slope of restitution (S max ) were assessed before and after TEA. VT/VF inducibility was assessed by programmed electrical stimulation. Results: TEA reduced inducibility of VT/VF by 70%. TEA did not affect RV-systolic pressure or contractility, although LV-systolic pressure and contractility decreased modestly. Global and regional ventricular ARIs increased, including in scar and border zone regions post-TEA. TEA reduced ARI dispersion specifically in border zone regions. Ventricular ERPs prolonged significantly at critical sites of arrhythmogenesis, and S max was reduced. Interestingly, TEA significantly improved cardiac vagal function, as measured by both BRS and intrinsic cardiac neural activity. Conclusion: TEA does not compromise RV function in infarcted hearts. Its anti-arrhythmic mechanisms are mediated by increases in ventricular ERP and ARIs, decreases in S max , and reductions in border zone heterogeneity. TEA improves parasympathetic function, which may independently underlie some of its observed anti-arrhythmic mechanisms. This study provides novel insights into the anti-arrhythmic mechanisms of TEA, while highlighting its applicability to the clinical setting. Abstract Illustration: Myocardial infarction is known to cause cardiac autonomic dysfunction characterized by sympathoexcitation coupled with reduced vagal tone. This pathological remodeling collectively predisposes to ventricular arrhythmia. Thoracic epidural anesthesia not only blocks central efferent sympathetic outflow, but by also blocking ascending projections of sympathetic afferents, relieving central inhibition of vagal function. These complementary autonomic effects of thoracic epidural anesthesia may thus restore autonomic balance, thereby improving ventricular electrical stability and suppressing arrhythmogenesis. DRG=dorsal root ganglion, SG=stellate ganglion.

Upregulation of CD8+ regulatory T cells following liver-directed AAV gene therapy.

Liver-directed AAV gene therapy represents a unique treatment modality for a host of diseases. This is due, in part, to the induction of tolerance to transgene products. Despite the plethora of recognized regulatory cells in the body, there is currently a lack of literature supporting the induction of non-CD4+ regulatory cells following hepatic AAV gene transfer. In this work, we show that CD8+ regulatory T cells are up-regulated in PBMCs of mice following capsid only and therapeutic transgene AAV administration. Further, we demonstrate that hepatic AAV gene transfer results in a significant increase in CD8+ regulatory T cells following experimental autoimmune encephalomyelitis induction. Notably, this response occurred only in therapeutic vector treated animals, not capsid only controls. Understanding the role these cells play in treatment efficacy will result in the development of improved AAV vectors that take advantage of the full gamut of regulatory cells within the body.

Patient Survival With Extended Home Hemodialysis Compared to In-Center Conventional Hemodialysis.

Introduction: More frequent and/or longer hemodialysis (HD) has been associated with improvements in numerous clinical outcomes in patients on dialysis. Home HD (HHD), which allows more frequent and/or longer dialysis with lower cost and flexibility in treatment planning, is not widely used worldwide. Although, retrospective studies have indicated better survival with HHD, this issue remains controversial. In this multicenter study, we compared thrice-weekly extended HHD with in-center conventional HD (ICHD) in a large patient population with a long-term follow-up. Methods: We matched 349 patients starting HHD between 2010 and 2014 with 1047 concurrent patients on ICHD by using propensity scores. Patients were followed-up with from their respective baseline until September 30, 2018. The primary outcome was overall survival. Secondary outcomes were technique survival; hospitalization; and changes in clinical, laboratory, and medication parameters. Results: The mean duration of dialysis session was 418 ± 54 minutes in HHD and 242 ± 10 minutes in patients on ICHD. All-cause mortality rate was 3.76 and 6.27 per 100 patient-years in the HHD and the ICHD groups, respectively. In the intention-to-treat analysis, HHD was associated with a 40% lower risk for all-cause mortality than ICHD (hazard ratio [HR] = 0.60; 95% confidence interval [CI] 0.45 to 0.80; P < 0.001). In HHD, the 5-year technical survival was 86.5%. HHD treatment provided better phosphate and blood pressure (BP) control, improvements in nutrition and inflammation, and reduction in hospitalization days and medication requirement. Conclusion: These results indicate that extended HHD is associated with higher survival and better outcomes compared to ICHD.

Integrated Care: A Person-Centered and Population Health Strategy for the COVID-19 Pandemic Recovery and Beyond.

The COVID-19 pandemic has mandated a re-imagination of how healthcare is administered and delivered, with a view towards focusing on person-centred care and advancing population health while increasing capacity, access and equity in the healthcare system. These goals can be achieved through healthcare integration. In 2019, the University Health Network (UHN), a consortium of four quaternary care hospitals in Ontario, Canada, established the first stage of a pilot program to increase healthcare integration at the institutional level and vertically with other primary, secondary and tertiary institutions in the Ontario healthcare system. Implementation of the program was accelerated during the COVID-19 pandemic and demonstrated how healthcare integration improves person-centred care and population health; therefore serving as the foundation for a health system response for the COVID-19 pandemic recovery and beyond.