Infarct size, inflammatory burden and admission hyperglycemia in diabetic patients with acute myocardial infarction treated with SGLT2-inhibitors: a multicenter international registry

Background

Sodium-glucose co-transporter 2 inhibitors (SGLT2-I) currently receive intense clinical interest in patients with and without diabetes mellitus (DM) with pleiotropic beneficial effects. Nowadays, the inflammation response in the setting of acute myocardial infarction (AMI) has been proposed as a potential pharmacological intervention target. In this setting, we tested the hypothesis that the SGLT2-I displays anti-inflammatory effect along with glucose-lowering properties. We investigated the relationship between stress hyperglycemia, inflammation burden and infarct size in a cohort of type 2 diabetic AMI patients treated with SGLT2-I versus other oral anti-diabetic (OAD) agents alone.

Methods

In this multicenter international registry, all diabetic patients with AMI treated with percutaneous coronary intervention (PCI) between 2018 and 2021 were enrolled. Based on the admission anti-diabetic therapy, patients were divided into those receiving SGLT2-I versus other OAD agents alone. Patients on insulin therapy alone or combined with OAD agents were excluded from the study. The following inflammatory markers were evaluated at different time points: total white blood cell, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and neutrophil-to-platelet ratio (NPR), C-reactive protein. Infarct size was assessed by peak troponin levels and echocardiographic parameters.

Results

The final study population consisted of 583 patients hospitalized for AMI (both STEMI and NSTEMI) classified as SGLT2-I users (n=98) versus other OAD agents alone (n=485). Admission hyperglycemia was more prevalent among the other OAD agents group. Reduced infarct size was detected in patients treated with SGLT2-I compared to those treated with other OAD agents alone. Both at admission, and after 24 hours, inflammatory indices were significantly higher in patients treated with other OAD agents alone, with a significant increase in neutrophils levels at 24 hours, compared to the SGLT2-I group. In multivariate analysis, SGLT2-I emerged as a significant predictor of reduced inflammatory response (OR 0.45, 95% CI 0.27–0.75, p=0.002), together with peak troponin values, independently of age, admission creatinine values and admission glycemia.

Conclusions

Type 2 Diabetic patients hospitalized for AMI and receiving SGLT2-I exhibited modest inflammatory response and myocardial damage/infarct size compared to other OAD agents alone, independently of glucose-metabolic control. Our findings pave the way for new pathophysiological and therapeutic insights regarding the cardioprotective effect of SGLT2-I in the setting of coronary artery disease.

Funding Acknowledgement

Type of funding sources: None.

Feasibility, safety and long term outcomes of complex left main bifurcation treatment using the nano inverted t stenting: a multicentre registry

Background

The role of double stenting techniques in distal bifurcation left main (LM) disease has gaining interest over the latest years.

Purpose

We present the 3-year multicentre registry outcomes of dual stenting using ultra-thin strut stents and the Nano Inverted-T (NIT) technique in complex unprotected true LM bifurcation disease.

Methods

We analysed the procedural and medical data of consecutive patients enrolled between 1st January 2014 and 1st December 2019 in a multicentre registry for complex LM bifurcation disease treated with the double stenting technique called NIT due contraindications and/or refusal to surgical treatment. Target lesion failure (TLF) was defined as the composite of cardiovascular death, target-vessel MI (TVMI) and clinically driven target lesion revascularization (TLR).

Results

Among two hundred-ninety-five patients (138 males, mean age 70.3±12.8 years), post-operative success was achieved in 100% of cases. Contrast volume, procedural time, and radiation exposure were 139.2±23.4 ml, 15.3±4.9 min, and 1080±1034 cGy/m2 (Figure), respectively. At a mean follow-up of 39.5±0.6 months TLF rate was 6.1% (n=18) while TLR and cardiovascular mortality rates were 3.0 (n=9) and 2.6% (n=8), respectively. Clinically driven angiographic follow-up was available in 26.4% of patients at a mean time from the procedure of 7.5±0.4 months. Clinically restenosis rate was 3.3%.

Conclusions

Revascularization of complex LM bifurcation disease using the NIT double stenting technique resulted feasible and safe with a low incidence of TLF, excellent survival rate and no stent thrombosis. Figure 1.The NIT technique is based on the use of ultra-thin strut (≤80 micron) stents and double stenting starting with side branch stenting frst. The side branch stent is precisely positioned with one possibly only strut protruding into the main vessel which is balloon crushed before the implantation of the main branch stenting. The Proximal optimization technique (POT)–snuggle kissing–POT sequence is mandatory to ensure the coverage of the side branch ostium by both side branch and main branch stents. Snuggle kissing was performed placing the LCX balloon with the proximal marker at the middle rather than at the proximal marker of the LM-LAD balloon, in order to minimize the elliptical deformation of the LM stent.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Baseline troponin-T is powerful predictor of mortality after coronary bifurcation stenting

Introduction

Considerable progress has been made in the treatment of coronary bifurcation stenosis. Anatomical characteristics of the lesion, however, fail to give information about the functional significance of the bifurcation stenosis. There is no study that systematically establishes the baseline functional significance of coronary stenosis and its effect on procedural and clinical outcomes.

Methods

Patients with significant angiographically bifurcation lesions defined as diameter stenosis >50% in main vessel and/or side branch were included. FFR was performed in main vessel (MV) and side branch (SB) before and after percutaneous coronary intervention (PCI). If FFR was ≤0.80 the lesion was considered functionally significant, and patients underwent PCI. For the group with FFR >0.80 – intervention was deferred. All patients were followed-up for vital status every 3 months. Cox regression analysis was performed to identify independent predictors of all-cause and cardiovascular death. The local ethics committee approved the study and patients signed informed consent for participation into registry.

Results

For mean follow-up of 38±18 months (median 40, IQR 23–55 months) all-cause mortality was numerically lower: 8.5% (n=7/82) in deferred group and 12.6% in stented group (n=11/76, p=0.387). The cardiac mortality was also numerically lower, but statistically not significant (9.8%, n=8/82 vs. 11.5%, n=10/88, p=0.714). On multivariate model, independent predictors were mitral regurgitation >1st degree – HR=1.778 (CI 1.100–2.874, p=0.019); dyslipidemia HR=0.765 (CI 0.594–0.985, p=0.038); hemoglobin concentration – HR=0.976 (CI 0.964–0.988, p<0.001); pre-PCI serum troponin ≥0.010 ng/ml – HR=2.702 (CI 1.451–5.032, p=0.002). On multivariate analysis, the following factors were identified as independent predictors of cardiac mortality: age – HR=1.035 (CI 1.009–1.062, p=0.009); diabetes – HR=1.789 (CI 1.089–2.962, p=0.024); dyslipidemia treated with statin – HR=0.667 (CI 0.515–0.863, p=0.002); LV posterior wall thickness – HR=1.230 (CI 1.062–1.424, p=0.006); mitral regurgitation more than 1st degree – HR=1.763 (CI 1.065–2.917, p=0.027); troponin pre-PCI ≥0.010 ng/ml – HR=2.498 (CI 1.228–5.081, p=0.011); true bifurcation lesion – HR=1.820 (CI 1.026–3.229, p=0.040); SBBARI score <10% – HR=1.715 (CI 1.049–2.804, p-0.031).

Conclusion

Baseline high-sensitive troponin T value is a strong predictor for both all cause and cardiac mortality in patients undergoing coronary bifurcation lesion PCI.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Alexandrovska University Hospital

Mid-term mortality after stenting of distal left main stenosis with regular, third generation drug eluting stent or dedicated bifurcation stent or surgery-registry based,all-comers data

Background

Distal left main (LM) bifurcation lesions remain a challenge for interventional cardiologists and they are associated with significant morbidity and mortality. The aim of the current study was to identify predictors of cardiac mortality at mid-term follow up after PCI (DES vs. dedicated bifurcation stent) or CABG.

Methods

All patients with distal LM stenosis ≥50% were included in prospective registry starting from 01.2015. The exclusion criteria for registry are cardiogenic shock, a priory life expectancy duration <1 year, lack of inform consent. All patients were prospectively followed about the alive status through the national security number data base. All deaths were deemed cardiac if proof otherwise (the data patient families or family's physicians were contacted through phone call about the reason of death)

Results

For three year follow up period (median 35 months, IQR 18–50) 303 patients were included. 220 patients were stented with 3rd generation DES, 43 with dedicated bifurcation stent BiOSS (Balton, Poland), and rest were sent for CABG. The mean age was 67±10 years, 72% were males, 37% diabetics, all with hypertension, 97% dyslipidemia, 15% PAD, 9% COPD, 16% carotid artery disease, previous MI 28%, previous PCI 50% - without significant difference between three groups. The frequency of acute coronary syndrome during admission was 11% - without difference in frequency between groups. The patient referred to CABG had significantly lower left ventricular EDV and ESV, more severe mitral regurgitation and kinetic disturbances, higher SYNTAX score and longer lesion length. On univariate COX regression analysis, the following factors were associated with mortality: age, NYHA class, GFR, baseline troponin, hemoglobin, LV EF, mitral regurgitation, kinetics disturbances, treatment with beta blockers, ACE inhibitors, statin, atrial fibrillation, SYNTAX score, lesion length. The type of treatment was not associated with differences in mortality (figure). On COX multiple regression survival analysis independent predictors of survival were: age (HR=1.036, CI 1.005–1.068, p=0.023); COPD (HR=2.313, CI 1.170–4.572, p=0.016); GFR (HR=0.988, CI 0.978–1.000, p=0.048); hemoglobin (HR=0.970, CI 0.955–0.986, p=0.000); left ventricular EF (HR=0.958, CI 0.832–0.985, p=0.003).

Conclusions

The type of treatment was not associated with mid-term mortality. Our data demonstrate that dedicated bifurcation stent could be used safely for distal LM stenosis treatment with similar safety as 3rd generation DES.

Funding Acknowledgement

Type of funding sources: None.

Origin Sample Prediction and Spatial Modeling of Antimicrobial Resistance in Metagenomic Sequencing Data

The steady elaboration of the Metagenomic and Metadesign of Subways and Urban Biomes (MetaSUB) international consortium project raises important new questions about the origin, variation, and antimicrobial resistance of the collected samples. CAMDA (Critical Assessment of Massive Data Analysis, http://camda.info/) forum organizes annual challenges where different bioinformatics and statistical approaches are tested on samples collected around the world for bacterial classification and prediction of geographical origin. This work proposes a method which not only predicts the locations of unknown samples, but also estimates the relative risk of antimicrobial resistance through spatial modeling. We introduce a new component in the standard analysis as we apply a Bayesian spatial convolution model which accounts for spatial structure of the data as defined by the longitude and latitude of the samples and assess the relative risk of antimicrobial resistance taxa across regions which is relevant to public health. We can then use the estimated relative risk as a new measure for antimicrobial resistance. We also compare the performance of several machine learning methods, such as Gradient Boosting Machine, Random Forest, and Neural Network to predict the geographical origin of the mystery samples. All three methods show consistent results with some superiority of Random Forest classifier. In our future work we can consider a broader class of spatial models and incorporate covariates related to the environment and climate profiles of the samples to achieve more reliable estimation of the relative risk related to antimicrobial resistance.

Predictors of long-term outcomes of coronary bifurcation stenting: 6-year results from international, randomized POLBOS I and POLBOS II clinical trials

Introduction

Bifurcation lesions pose a therapeutic challenge during percutaneous coronary intervention (PCI). Results of regular drug-eluting stents (rDESs) in bifurcation treatment are not optimal.

Purpose

The aim of this study was to analyze the 6-year follow-up of BiOSS (Balton, Poland) stents in patients enrolled into two randomized clinical trials POLBOS I (NCT02192840) and POLBOS II NCT02198300).

Methods

The BiOSS stent is a coronary dedicated bifurcation balloon expandable stent made of 316L stainless steel and coated with a biodegradable polymer as well as the drug. The stent consists of two parts with different diameters connected with two struts of 1.9 - 2.5 mm length each. The aim of randomized POLBOS trials was to compare the BiOSS stents with regular drug eluting stents (rDES) in patients with stable CAD or NSTE-ACS (POLBOS I: paclitaxel eluting BiOSS Expert vs rDES; POLBOS II: sirolimus eluting BiOSS LIM vs rDES). Provisional T-stenting was the default strategy. Angiographic control was performed at 12 months in all patients. The primary end-point was composed MACE defined as cardiac death, myocardial infarction or target lesion revascularization (TLR). Clinical assessment was performed every year after index procedure.

Results

In POLBOS I trial BiOSS Expert was implanted in 120 patients (49.4%), and rDES was implanted in 123 patients. The target vessel was the left anterior descending (LAD) artery (52% vs 70%) followed by the left main stem (LMS) coronary artery (22% vs 15%). In rDES group, 38.2% of patients received paclitaxel-eluting stents. Side branch treatment with rDES was required in 10% of cases in both groups. At 12 months, the incidence of cumulative major adverse cardiovascular events (MACE) was similar in both groups: 13.3% vs 12.2% (P=0.7). The TLR rate was significantly higher in the BiOSS Expert group compared with rDES group (11.5% vs 7.3%; P=0.02). Significantly lower rates of restenosis were observed in final kissing balloon (FKB) subgroups of both the BiOSS Expert (8.1% vs 13.2%; P<0.05) and rDES groups (4.9% vs 9.5%; P<0.05).

In POLBOS II 202 patients were randomly assigned 1:1 to treatment of the coronary bifurcation lesions either with the BiOSS LIM stent (n=102) or with rDES (n=100). The target vessel was the LAD (44% vs 43%) followed by the LMS (35.3% vs 38%). Side branch treatment was required in 8.8% (rDES) and 7% (BiOSS). At 12 months, the cumulative MACE incidence was similar in both groups (11.8% [BiOSS] vs. 15% [rDES, p=0.08]), as was the TLR rate (9.8% vs. 9% [p=0.8]). The binary restenosis rates were significantly lower in the FKBI subgroup of the BiOSS group (5.9% vs. 11.8%, p<0.05).

At the time of ESC Congress 2020 we will present data from 6-year follow-up from POLBOS I trial and POLBOS II trial focusing on LM stenting and patients with diabetes.

Conclusions

BiOSS® stents provided satisfactory 1-year results which seemed comparable with rDES. Long-term data are pending.

Funding Acknowledgement

Type of funding source: None

Using Machine Learning in Accuracy Assessment of Knowledge-Based Energy and Frequency Base Likelihood in Protein Structures

Many aspects of the study of protein folding and dynamics have been affected by the accumulation of data about native protein structures and recent advances in machine learning. Computational methods for predicting protein structures from their sequences are now heavily based on machine learning tools and on approaches that extract knowledge and rules from data using probabilistic models. Many of these methods use scoring functions to determine which structure best fits a native protein sequence. Using computational approaches, we obtained two scoring functions: knowledge-based energy and likelihood of base frequency, and we compared their accuracy in measuring the sequence structure fit. We compared the machine learning models’ accuracy of predictions for knowledge-based energy and likelihood values to validate our results, showing that likelihood is a more accurate scoring function than knowledge-based energy.

A novel framework for horizontal and vertical data integration in cancer studies with application to survival time prediction models

Background

Recently high-throughput technologies have been massively used alongside clinical tests to study various types of cancer. Data generated in such large-scale studies are heterogeneous, of different types and formats. With lack of effective integration strategies novel models are necessary for efficient and operative data integration, where both clinical and molecular information can be effectively joined for storage, access and ease of use. Such models, combined with machine learning methods for accurate prediction of survival time in cancer studies, can yield novel insights into disease development and lead to precise personalized therapies.

Results

We developed an approach for intelligent data integration of two cancer datasets (breast cancer and neuroblastoma) − provided in the CAMDA 2018 ‘Cancer Data Integration Challenge’, and compared models for prediction of survival time. We developed a novel semantic network-based data integration framework that utilizes NoSQL databases, where we combined clinical and expression profile data, using both raw data records and external knowledge sources. Utilizing the integrated data we introduced Tumor Integrated Clinical Feature (TICF) − a new feature for accurate prediction of patient survival time. Finally, we applied and validated several machine learning models for survival time prediction.

Conclusion

We developed a framework for semantic integration of clinical and omics data that can borrow information across multiple cancer studies. By linking data with external domain knowledge sources our approach facilitates enrichment of the studied data by discovery of internal relations. The proposed and validated machine learning models for survival time prediction yielded accurate results.

Reviewers

This article was reviewed by Eran Elhaik, Wenzhong Xiao and Carlos Loucera.

P1963The determinants of functional significance of coronary bifurcation lesions and its implications on clinical follow up to 48 months (insights from FIESTA registry)

Background

There is no study up-to-now to determine the rate of functionally significant coronary bifurcation lesions, which have to be intervened and what are the clinical consequences of the FFR case selection strategy.

Methods

We analyzed patients from FIESTA registry, which was continuation of FIESTA study (Ffr vs. IcEcgSTA, ClinicalTrials.gov Identifier: NCT01724957). Patients with stable angina were included (if there were other coronary stenoses they were threated first after checking by FFR for functional significance). The inclusion criterions were angiographic bifurcation lesions in a native coronary artery with diameter ≥2.5 mm and ≤4.5 mm and SB diameter ≥2.0 mm. We excluded patients with ST-segment elevation myocardial infarction, left main, hemodynamic instability and those with non-cardiac co-morbidity conditions with a life expectancy of less than one year. PCI was performed according to the current guidelines. Provisional stenting was the default strategy in all patients. Two guidewires were inserted into both distal MB and SB. Initial FFR was performed using the PrimeWire or PrimeWire Prestige (Volcano Corp., USA). For all FFR measurements, intracoronary adenosine was given in increasing doses of 60 mcg, 120 mcg, and 240 mcg. The minimum value of FFR measurements was taken for analysis. All patients received double antiplatelet therapy with ADP-antagonist and aspirin for at least 12 months.

Results

A 130 consecutive patients with coronary bifurcation stenoses were included – 57 had positive FFR<.80 in main vessel of bifurcation lesion (44% functionally significant lesions). The mean age was 67±10 years, 66% males, 96% hypertensive, 39% diabetic, 96% dyslipidemic (or on treatment with statin), 55% smokers, 22% with previous myocardial infarction, 51% with previous PCI. The residual SYNTAX score before FFR bifurcation assessment was 13±4 (FFR<.80) vs. 8±3 (FFR≥0.80), p<0.001. Univariate predictors of bifurcation FFR<.80 were: proximal (MV%DS) or distal (MB%DS) main vessel stenosis ≥85% (derived from ROC analysis with overall accuracy 77% and 72%, accordingly), lesion length, SYNTAX score, triglyceride concentration, previous MI on lateral wall and carotid artery disease. On multivariate logistic analysis only MV%DS>85% (OR=8.929, CI 2.887–27.619, p<0.001), MB%DS>85% (OR=3.831, CI 1.349–10.883, p=0.012) and SYNTAX score≥12 (OR=16.466, CI 5.225–15.889, p<0.001). At median follow-up of 26 months (IQR 17–35) the all-cause mortality was 17.5% in FFR positive bifurcations vs. 4.1% in FFR negative lesions (log-rank =.067).

Conclusions

Less than a half of angiographically significant coronary bifurcation lesions are functionally significant and require stent implantation. The functional significance was related with higher degree stenosis in main vessel and overall disease severity estimated with SYNTAX score. A trend to lower mortality was noted in group with non-significant FFRs.

Experiences with workflows for automating data-intensive bioinformatics

High-throughput technologies, such as next-generation sequencing, have turned molecular biology into a data-intensive discipline, requiring bioinformaticians to use high-performance computing resources and carry out data management and analysis tasks on large scale. Workflow systems can be useful to simplify construction of analysis pipelines that automate tasks, support reproducibility and provide measures for fault-tolerance. However, workflow systems can incur significant development and administration overhead so bioinformatics pipelines are often still built without them. We present the experiences with workflows and workflow systems within the bioinformatics community participating in a series of hackathons and workshops of the EU COST action SeqAhead. The organizations are working on similar problems, but we have addressed them with different strategies and solutions. This fragmentation of efforts is inefficient and leads to redundant and incompatible solutions. Based on our experiences we define a set of recommendations for future systems to enable efficient yet simple bioinformatics workflow construction and execution.

Reviewers

This article was reviewed by Dr Andrew Clark.

Double bifurcation optimization stent system technique for left main stenosis

We present a first-in-man case with implantation in culottes' fashion of two dedicated coronary bifurcation stents (BiOSS Lim) in distal left main stenosis. The immediate procedural and very short-term result was excellent.

A Semi-Automated Approach for Anatomical Ontology Mapping

This paper presents a study in the domain of semi-automated and fully-automated ontology mapping. A process for inferring additional cross-ontology links within the domain of anatomical ontologies is presented and evaluated on pairs from three model organisms. The results of experiments performed with various external knowledge sources and scoring schemes are discussed.

A semi-automated approach for anatomical ontology mapping

This paper presents a study in the domain of semi-automated and fully-automated ontology mapping. A process for inferring additional cross-ontology links within the domain of anatomical ontologies is presented and evaluated on pairs from three model organisms. The results of experiments performed with various external knowledge sources and scoring schemes are discussed.

N-methylcodeinium iodide--crystal structure and spectroscopic elucidation

The correlation between the structure and the spectroscopic properties of N-methylcodeinium iodide (1) has been studied, using the methods of single crystal X-ray diffraction, IR-LD spectroscopy of oriented samples as a suspension in nematic liquid crystals, UV-vis spectroscopy and 1H and 13C NMR spectroscopy. HPLC tandem mass spectrometry (HPLC ESI MS/MS) and thermal methods were also employed. Quantum chemical calculations have been performed with a view to obtaining the electronic structure and vibrational properties of the title compound. Compound (1) crystallizes in the space group P2(1)2(1)2(1) and its cations and anions are joined by moderate intermolecular OH...I- interaction of length 3.442A. The codeine molecule exhibits the classical T-shape for opiates. A dihedral angle value of 86.4(5) degrees between the A/B/C and D/E planes is obtained. Rings A and B are effectively coplanar with an interplanar angle of 3.6(3) degrees.

In vivo quantification of endotoxin-induced nitric oxide production in pigs from Na15NO3-infusion

1. In this investigation the NO production rate is quantified in the pig during normotensive endotoxin-induced shock with increased cardiac output and during subsequent treatment with the NO synthase inhibitor N omega-monomethy-L-arginine (L-NMMA). NO production rate was derived from the plasma isotope-enrichment of 15N-labelled nitrate (15NO3-). 2. Three groups of animals (control, n = 5; endotoxin, n = 6; endotoxin + L-NMMA, n = 6) were anaesthetized and instrumented for the measurement of systemic and pulmonary haemodynamics. Each animal received a primed-continuous infusion of stable, non-radioactively labelled Na15 NO3 (bolus 30 mg, infusion rate 2.1 mg h-1). Arterial blood samples were taken 5, 10, 15, 30, 60 and 90 min later and every 90 minutes until the end of the experiment. 3. Continuous i.v. infusion of endotoxin was incrementally adjusted until mean pulmonary artery pressure (PAP) reached 50 mmHg and subsequently titrated to keep mean PAP approximately 35 mmHg. Hydroxyethylstarch was administered as required to maintain mean arterial pressure (MAP) > 60 mmHg. Six hours after the start of the endotoxin continuous i.v. L-NMMA (1 mg kg-1 h-1) was administered to the endotoxin + L-NMMA group. Haemodynamic data were measured before as well as 9 h after the start of the endotoxin. 4. After conversion of NO3- to nitro-trimethoxybenzene and gas chromatography-mass spectrometry analysis the total NO3- pool, basal NO3- production rate and the increase per unit time in NO3- production rate were calculated from the time-course of the 15NO3- plasma isotope-enrichment. A two compartment model was assumed for the NO3- kinetics, one being an active pool in which newly generated NO3- appears and from which it is eliminated, the other being an inactive volume of distribution in which only passive exchange takes place with the active compartment. 5. Although MAP did not change during endotoxin infusion alone, cardiac output (CO) increased by 42 +/- 40% (P < 0.05 versus baseline) by the end of the experiment due to a significant (P < 0.05 versus baseline) fall in systemic vascular resistance (SVR) to 65 +/- 25% of the baseline value. L-NMMA given with endotoxin did not change MAP, and both CO and SVR were maintained close to the pre-shock levels. 6. Baseline plasma NO3- concentrations were 43 +/- 13 and 40 +/- 10 mumol l-1 in the control and endotoxin animals, respectively, and did not differ at the end of the experiment (39 +/- 8 and 44 +/- 15 mumol l-1, respectively). The mean NO3- pool and basal NO3- production rate were 1155 +/- 294 mumol and 140 +/- 32 mumol h-1, respectively, without any intergroup difference. Endotoxin significantly increased NO3- production rate (23 +/- 10 mumol h-2, P < 0.05 versus control (6 +/- 7 mumol h-2) and endotoxin + L-NMMA groups). L-NMMA given with endotoxin (-1 +/- 2 mumol h-2, P < 0.05 versus control and endotoxin groups) had no effect. 7. Analysis of the time course of the 15NO3- plasma isotope enrichment during primed-continuous infusion of Na15NO3 allowed us to quantify the endotoxin-induced increase in NO3- production rate independently of total NO3- plasma concentrations. Low-dose L-NMMA blunted the increase in NO3- production rate while maintaining basal NO3- formation.