Added Sodium Nitrite Research Articles

Impacts of corrosion inhibiting admixture and supplementary cementitious material on early strength concrete

This research aimed to evaluate the influence of alccofine 1203 on a mineral admixture and sodium nitrite as a corrosion inhibitor on the properties of concrete. To achieve these aims, an experimental investigation was carried out on a set of composite samples comprising five distinct concrete formulations. Five different mixes for the concrete were used as the overlay materials such as NC as a reference concrete, alccofine concrete (i.e. 25% cement replaced with alccofine), and alccofine concrete with varying dosages of sodium nitrite (i.e. 1%, 1.25%, and 1.5%). Alccofine reduced the workability and water absorption and increased the compressive strength of the concrete (5%) at curing age of 28 days. Adding sodium nitrite further reduced water absorption of the concrete and workability but compressive strength of 29.15% and 26.93% for the curing period of 3 and 7 days, respectively. The pH of the concrete powdered solution became more alkaline with the replacement of alccofine and addition of sodium nitrite. Free chloride content dropped by 48 and 66%, respectively, with the introduction of GGBS and sodium nitrite. Corrosion properties of the concrete samples were examined using open circuit potentials and linear polarization resistance of various concrete mixes after being immersed in 1 M H2SO4 and 3% NaCl environment. The findings indicated a notable improvement in the corrosion resistance, water absorption test, thermal conductivity, strength properties, and microstructural properties of concrete with the incorporation of SN in combination with alccofine. The application of the response surface method allowed for the prediction, validation, and optimization of experimental data using a regression equation.

Enhancing quality control in emulsion-type sausage production: Predicting chemical composition of intact samples with near infrared spectroscopy

This research actively explores the potential of near infrared spectroscopy (NIR) for analyzing the chemical composition of emulsion-type sausages, focusing on critical factors like residual nitrite, moisture, protein, and fat content. To establish robust and generalizable models, we utilized a dataset of 100 experimentally prepared sausages encompassing a wide range of pork back fat replacement levels (5%, 15%, 30%, 45%, and 60%) and added sodium nitrite amounts (0, 80, 125, 250, and 375 ppm). An external validation set of 20 commercially sourced sausages further assessed the model’s real-world applicability. Partial least squares (PLS) regression calibration models with multiplicative scatter correction (MSC) pre-treatment demonstrated impressive accuracy for moisture (RMSECV = 0.57%, RPD = 9.8), fat (RMSECV = 1.17%, RPD = 9.5), and protein (RMSECV = 0.30%, RPD = 7.6). While residual nitrite prediction presented challenges due to its inherent complexity, the external validation yielded a competitive root mean square error of prediction (RMSEP) of 12.02 ppm, surpassing the average performance reported in similar studies (RMSEP ∼15 ppm) by 3 ppm. Importantly, sample homogenization did not significantly affect parameter prediction, highlighting the robustness of the NIR-based approach. These findings suggest that NIR spectroscopy, with its non-destructive, rapid, and cost-effective nature, could provide valuable tools for quality control and monitoring in the emulsion-type sausage industry. More importantly, improved nitrite prediction could pave the way for enhanced precision and control in sausage production, ultimately contributing to improved food safety and sustainability.

Electrochemical Diagnosis of Urinary Tract Infection Using Boron-Doped Diamond Electrodes.

Efficient detection of sodium nitrite in human urine could be used to diagnose urinary tract infections rapidly. Here, we demonstrate a fast and novel method for the selective detection of sodium nitrite in different human urine samples using electrolysis with a bare boron-doped diamond electrode. The measurement is performed without adding any other species, such as enzymes, and uses a simple electrochemical approach with an oxidation step followed by reduction. In the present study, we pay attention to the reduction potential range for the measurement, which is substantially different from many previous literature reports that focus on the oxidation reaction. The determination of added sodium nitrite based on cyclic voltammetry or differential pulse voltammetry is employed for two pooled urine samples and three individual urine matrices. From this, the linear response ranges for sodium nitrite detection are 0.5-10 mg/L (7.2-140 μmol/L) and 10-400 mg/L (140-5800 μmol/L). The results from these urine samples convert well to the calibration curve, with a limit of detection established as 0.82 mg/L (R2 = 0.9914), which is clinically relevant.

Assessment of Nitrite Content in Vienna Chicken Sausages Using Near-Infrared Hyperspectral Imaging.

Sodium nitrite is a food additive commonly used in sausages, but legally, the unsafe levels of nitrite in sausage should be less than 80 mg/kg, since higher levels can be harmful to consumers. Consumers must rely on processors to conform to these levels. Therefore, the determination of nitrite content in chicken sausages using near infrared hyperspectral imaging (NIR-HSI) was investigated. A total of 140 chicken sausage samples were produced by adding sodium nitrite in various levels. The samples were divided into a calibration set (n = 94) and a prediction set (n = 46). Quantitative analysis, to detect nitrate in the sausages, and qualitative analysis, to classify nitrite levels, were undertaken in order to evaluate whether individual sausages had safe levels or non-safe levels of nitrite. NIR-HSI was preprocessed to obtain the optimum conditions for establishing the models. The results showed that the model from the partial least squares regression (PLSR) gave the most reliable performance, with a coefficient of determination of prediction (Rp) of 0.92 and a root mean square error of prediction (RMSEP) of 15.603 mg/kg. The results of the classification using the partial least square-discriminant analysis (PLS-DA) showed a satisfied accuracy for prediction of 91.30%. It was therefore concluded that they were sufficiently accurate for screening and that NIR-HSI has the potential to be used for the fast, accurate and reliable assessment of nitrite content in chicken sausages.

Property improvement of a thermoplastic starch/poly(butylene adipate-co-terephthalate) blown film by the addition of sodium nitrite

Recently, global awareness of the adverse environmental impacts of single-use plastics has risen due to their nonbiodegradability and likelihood of ending up in the ocean. Thermoplastic starch (TPS) is an alternative material employed for manufacturing single-use products because of its high biodegradability, nontoxicity, and low cost. However, TPS is moisture sensitive and has poor mechanical properties and processability. Blending TPS with biodegradable polyesters, including poly(butylene adipate-co-terephthalate) (PBAT), can expand its practical applications. This research aims to improve the performance of TPS/PBAT blends by adding sodium nitrite, a food additive, and considering its effect on the morphological characteristics and properties of TPS/PBAT blends. TPS/PBAT/sodium nitrite (TPS/PBAT/N) blends with a TPS:PBAT weight ratio of 40:60 and sodium nitrite concentrations of 0.5, 1, 1.5, and 2 wt% were prepared by extrusion and then blown into films. The acids generated from the sodium nitrite during extrusion led to the molecular weight reduction of starch and PBAT polymers, causing the increased melt flow ability of the TPS/PBAT/N blends. The incorporation of sodium nitrite improved the blends' homogeneity and the compatibility between the TPS and PBAT phases, resulting in the increased tensile strength, extensibility, impact strength, and oxygen barrier properties of the TPS/PBAT blend film.

Levels of nitrate, nitrite and nitrosamines in model sausages during heat treatment and in vitro digestion – The impact of adding nitrite and spinach (Spinacia oleracea L.)

Nitrite derivatives react with endogenous precursors forming N-nitrosamines associated with development of colorectal cancer. The present study aims to investigate the formation of N-nitrosamines in sausage during processing and in vitro gastrointestinal digestion after adding sodium nitrite and/or spinach emulsion. The INFOGEST digestion protocol was used to simulate the oral, gastric, and small intestinal phases of digestion, and sodium nitrite was added in the oral phase to mimic the input of nitrite from saliva as it has shown to affect the endogenous formation of N-nitrosamines. The results show that the addition of spinach emulsion, in spite of it being a source of nitrate, did not affect the nitrite content in either batter, sausage, or roasted sausage. The levels of N-nitrosamines increased with the added amount of sodium nitrite, and further formation of some volatile N-nitrosamines was observed during roasting and in vitro digestion. In general, N-nitrosamine levels in the intestinal phase followed the same trend as in the undigested products. The results further indicate that nitrite present in saliva may cause a significant increase in N-nitrosamine levels in the gastrointestinal tract and that bioactive components in spinach may protect against the formation of volatile N-nitrosamines both during roasting and digestion.

Investigating the Antioxidant Potential of Bell Pepper Processing By-Products for the Development of Value-Added Sausage Formulations

Nowadays, when the supply chain of natural compounds for the production of value-added meat products is limited, the use of by-products from vegetable processing could become an attractive solution, contributing to the concept of circular economy. In this regard, our study investigated the effectiveness of yellow and red bell pepper processing by-products used in dried form (DYBPB, DRBPB) in the sausages recipe, instead of synthetic nitrites, to enhance their oxidative stability during cold storage (4 °C) for 20 days. Two types of nitrite-free sausages were obtained, such as smoked and dried sausages (I) and smoked and blanched sausages (II). Nitrite-free sausage formulations were designed by adding DYBPB and DRBPB at a dose to ensure a total phenolic compounds (TPC) level of 50, 90, 180, and 270 mg gallic acid equivalents (GAE)/kg of processed meat. The formulations developed were compared with control samples of sausages obtained with added sodium nitrite or without any additive. The DYBPB and DRBPB were investigated for total and individual phenolic content, total flavonoid content and antioxidant activity. The obtained sausages were investigated in terms of proximate composition as well as lipid oxidation progression based on specific chemical indices such as peroxide value (PV), p-anisidine value (p-AV), TOTOX index, and thiobarbituric acid (TBA) test during cold storage for 1, 10, and 20 days. The antioxidant activity of DYBPB and DRBPB has been shown to be closely related to their total phenolic content and total flavonoid content. It was found that a higher inhibitory potential against oxidative damage was evidenced in smoked and scalded sausages compared to smoked and dried formulations when the same dose of bell pepper processing by-products was applied. Our results showed that the use of dried bell pepper processing by-products in a dose that provides a TPC of a minimum of 180 mg GAE/kg processed meat for DRBPB and 270 mg GAE/kg processed meat for DYBPB have the potential to ensure lipid oxidative stability during cold storage of sausages for 20 days and can be considered for obtaininginnovative nitrite-free sausage formulations. Bearing in mind that the meat industry is currently looking for natural and sustainable ingredients to replace synthetic ones, our research recommends bell pepper processing by-products as promising substitutes for sodium nitrite to develop value-added meat products.

In vitro digestion of nitrite and nitrate preserved fermented sausages - New understandings of nitroso-compounds' chemical reactivity in the digestive tract.

In vitro digestions of dry-cured sausages formulated with four different rates of added sodium nitrite and sodium nitrate (NaNO2 / NaNO3, in ppm: 0/0; 80/80; 120/120; 0/200) were performed with a dynamic gastrointestinal digester (DIDGI®). The chemical reactivity of the potentially toxic nitroso-compounds (NOCs), oxidation reactions products and different iron types were evaluated over time. No nitrite nor nitrate dose effect was observed on NOCs' chemical reactivity. Nitrosothiols were scarce, and nitrosylheme was destabilized for every conditions, possibly leading to free iron release in the digestive tract. Total noN-volatile N-nitrosamines concentrations increased in the gastric compartment while residual nitrites and nitrates remained stable. The minimal rate of 80/80ppm nitrite/nitrate was enough to protect against lipid oxidation in the digestive tract. The present results provide new insights into the digestive chemistry of dry sausages, and into new reasonable arguments to reduce the load of additives in formulations.

Synthesis and antibacterial activity of some novel nucleus N-aminorhodanine based bis monofunctional and bifunctional reactive dyes and their application on wool and cotton fabrics

Hiren, we aimed to synthesis two new reactive dyes based on derivatives of Aminorodanine as a chromoforic group, as well as to apply the dye and antibacterial activity to the dyed fabric. First, we synthesized 3-amino rhodanine with glutaraldehyde and terephalaldhyde (2: 1 mole) to form compounds A & B respectively. After that we prepared monofunctional monochlorotriazine (MCT) and bifunctional monochlorotiazine sulphatoethyl sulphone (MCT/SES) by first condensation m- phenylene diamine sulphonic acid with Cyanuric chloride (1:1 mole) in ice bath then the second condensation takes place with sulfanilic acid or 1-Aminobenzene-4-β-sulfatoethylsulfone (PABSES) (1:1 mole) at room temperature; the pH was maintained at 5-6 by simultaneous addition 2 M sodium carbonate solution to form monofunctional reactive group C and bifunctional reactive group D respectively. Finally, we synthesized dyes by diazotized C and D by adding sodium nitrite (0.01 mol) to appropriate amines (0.01 mole) in concentrated HCl (6 ml) at (0-5 oC) under stirring then coupling with compounds A and B after dissolved them in ethanol with 2 M of sodium carbonate by 2 mol of the diazonium salt with 1 mole of coupler. The reactive dyes bis MCT 1, 2 and Bis MCT/SES 3, 4 are formed. We provided synthesized dyes structures by elemental analysis, IR, and 1HNMR spectroscopy. These dyes are used in dyeing cotton and wool that show good light fastness, and are excellent for washing, rubbing, and sweating fastness. Also, we measure antibacterial activity for cotton and wool fabrics toward Gram-negative and Gram-positive

Effects of adding sodium nitrite and tea polyphenols on the characterizations and cytotoxicity of carbon nanoparticles from fried pork

Carbon nanoparticles (CNPs) extensively present in thermal-processed foods. Sodium nitrite (NaNO2) and tea polyphenols (TP) are commonly used in meat processing, while the properties and cytotoxicity of CNPs existed in fried pork added NaNO2 and TP remain unknown. The results showed that compared with no addition (NA, 4.008 ± 0.43 nm) in soaked pork, the smaller diameters of CNPs (0.968 ± 0.44 nm) were found in CNPs-NaNO2-20 group (addition 20 mg/kg NaNO2), the larger (155.8 ± 7.30 nm) in CNPs-TP-100 group (addition 100 mg/kg TP). The diameter of CNPs was positively correlated with the added concentration. CNPs decreased the viability of HL-7702 cells. Compared with NA group, cell viability in CNPs-NaNO2-80 group was obviously (p < 0.05) decreased by 3.17%, while the CNPs-TP-200 group was 13.84% higher. CNPs could block cells growth by arresting cells in S-phase and increasing cellular ROS levels. CNPs generated in fired pork added 200 mg/kg TP in soaking showed less cytotoxicity.

Sodium nitrite as a corrosion inhibitor of copper in simulated cooling water

The corrosion inhibition behavior of sodium nitrite (NaNO2) towards pure copper (99.95%) in simulated cooling water (SCW) was investigated by means of electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). NaNO2 interferes with metal dissolution and reduce the corrosion rate through the formation or maintenance of inhibitive film on the metal surface. Surface morphologies illustrated that the surface homogeneity increased on adding sodium nitrite. Sodium nitrite’s adsorption on copper surface followed the modified form of Langmuir, Freundlich and Frumkin isotherms. Physiosorption mode was involved in the corrosion protection. Electrochemical results revealed an corrosion resistance of copper increases on increasing the inhibitor concentration. The DEIS results indicated that copper corrosion mechanism could be hindered by 50% even after interval of 24 h by optimum concentration of sodium nitrite. The maximum inhibition was achieved with 2000 ppm of NaNO2. With this concentration, inhibition efficiency of up to 61.8% was achievable.

New Insights into the Chemical Reactivity of Dry-Cured Fermented Sausages: Focus on Nitrosation, Nitrosylation and Oxidation.

Nitrite and nitrate are added to cured meat for their bacteriological, technological and sensorial properties. However, they are suspected to be involved in the formation of nitroso compounds (NOCs), such as potentially mutagenic nitrosamines, nitrosylheme and nitrosothiols. Controlling the sanitary and sensorial qualities of cured meat products by reducing these additives requires elucidating the mechanisms involved in the formation of NOCs. To this end, we studied the dose-response relationship of added sodium nitrite and/or sodium nitrate (0/0, 80/80, 0/200, and 120/120 ppm) on the formation of NOCs in dry cured fermented sausages. The results showed a basal heme iron nitrosylation in the absence of NaNO2/NaNO3 due to starter cultures. This reaction was promoted by the addition of NaNO2/NaNO3 in the other conditions. Reducing the dose to 80/80 ppm still limits lipid oxidation without the formation of non-volatile nitrosamines. Conversely, the addition of NO2/NO3 slightly increases protein oxidation through higher carbonyl content. The use of 80/80 ppm could be a means of reducing these additives in dry-cured fermented meat products.

Restraint effect of coexisting nitrite ion in simulated high level liquid waste on releasing volatile ruthenium under boiling condition

ABSTRACT In the ‘evaporation and dryness due to the loss of cooling functions,’ which is one of the severe accidents at reprocessing plants in Japan, volatile ruthenium (Ru) compound is possible to be produced and released from high level liquid waste (HLLW) in the storage tank to the environment. This cause is considered that the volatile Ru compound is produced from ruthenium nitrosyl nitrate by oxidizability of HNO3 in HLLW and released. We consider that the release of the volatile Ru compound from the HLLW can be restrained by coexisting nitrite ion because of its reduction power. To confirm the effect of nitrite ion on the release behavior of the volatile Ru compound, four experiments of heating the simulated HLLW (SHLLW) with setting the concentration of nitrite ion in the SHLLW as a parameter were carried out. As a result, the release of the volatile Ru compound was seemed to be restrained by adding sodium nitrite as a source of nitrite ion under certain boiling condition. This result may contribute to improve source term analysis in the evaporation and dryness due to the loss of cooling functions.

Effect of Sodium Nitrite Addition on the Corrosion Resistance of Manganese Phosphate Coating

This paper describes an effective metal finishing technology for obtaining manganese phosphate coatings on steel. In this study, the effect of sodium nitrite addition on the corrosion resistance of a manganese phosphate coating was investigated. The microstructure, surface morphology, and chemical composition were analyzed by FE-SEM, EDS, and XRD, while the cross-sectional images and thickness of the coating layer were analyzed by FIB. According to the results of the EDS analysis, the main components of the manganese phosphate coating were C, O, P, Mn, and Fe. The XRD results showed that (Mn,Fe)5H2(PO4)4 4H2O in the manganese phosphate coating layer was formed by a chemical reaction between manganese phosphate and elements in the underlying carbon steel. Additionally, electrochemical polarization testing was carried out in order to evaluate the corrosion protection properties of the manganese phosphate coating in a 3.5 wt.% NaCl solution. The corrosion resistance of the phosphate coating was remarkably improved by adding sodium nitrite.

Thyme and Clove Essential Oils as Antioxidants and Antimicrobial in Beef Sausage

Sausage is one of the well-liked foodstuffs in many areas. However, its quality is vulnerable to deteriorate owing to the lipid oxidation and microbial contamination. This research aimed to study the influence of thyme and clove essential oils (EOs) with or without nitrite on the chemical composition, microbial growth, and lipid oxidation rate in sausage during frozen storage-18°C for three months. The obtained results showed that the main component in clove EO and thyme EO is eugenol and thymol. Adding sodium nitrite to sausage resulted in declines in moisture and crude lipids and increases in protein and ash contents of sausage. Adding the tested EOs increased nitrite's effect on the chemical composition of sausage. Besides, these EOs lowered TBARS values, residual nitrite, and TBC in sausage. They also resulted in the rise of nitrite's efficacy in reducing TBARS values and TBC in sausage. Proteus was more sensitive than Klebsiella, whereas E. coli showed more resistance when adding nitrite or EO to sausage. The tested EOs increased the inhibitory influence of nitrite on Proteus, Klebsiella, Aspergillus niger, and Candida albicans in sausage. We concluded that the EOs of clove and thyme have antioxidant and antimicrobial efficacies in raw beef sausage during frozen storage. Also, they have a synergistic impact on nitrite. Therefore, it is suggested that these EOs, especially thyme, could be utilized to prolong shelf-life, prevent deterioration of sausage, and lessen the added nitrite's proportion to sausage for avoiding the formation of carcinogenic N-nitrosamines‏.

Vascular smooth muscle cell-specific progerin expression in a mouse model of Hutchinson-Gilford progeria syndrome promotes arterial stiffness: Therapeutic effect of dietary nitrite.

Vascular stiffness is a major cause of cardiovascular disease during normal aging and in Hutchinson–Gilford progeria syndrome (HGPS), a rare genetic disorder caused by ubiquitous progerin expression. This mutant form of lamin A causes premature aging associated with cardiovascular alterations that lead to death at an average age of 14.6 years. We investigated the mechanisms underlying vessel stiffness in LmnaG609G/G609G mice with ubiquitous progerin expression, and tested the effect of treatment with nitrites. We also bred LmnaLCS/LCSTie2Cre+/tgand LmnaLCS/LCSSM22αCre+/tg mice, which express progerin specifically in endothelial cells (ECs) and in vascular smooth muscle cells (VSMCs), respectively, to determine the specific contribution of each cell type to vascular pathology. We found vessel stiffness and inward remodeling in arteries of LmnaG609G/G609G and LmnaLCS/LCSSM22αCre+/tg, but not in those from LmnaLCS/LCSTie2Cre+/tgmice. Structural alterations in aortas of progeroid mice were associated with decreased smooth muscle tissue content, increased collagen deposition, and decreased transverse waving of elastin layers in the media. Functional studies identified collagen (unlike elastin and the cytoskeleton) as an underlying cause of aortic stiffness in progeroid mice. Consistent with this, we found increased deposition of collagens III, IV, V, and XII in the media of progeroid aortas. Vessel stiffness and inward remodeling in progeroid mice were prevented by adding sodium nitrite in drinking water. In conclusion, LmnaG609G/G609G arteries exhibit stiffness and inward remodeling, mainly due to progerin‐induced damage to VSMCs, which causes increased deposition of medial collagen and a secondary alteration in elastin structure. Treatment with nitrites prevents vascular stiffness in progeria.

DETECTION OF MUTAGENICITY IN SOME CURED MEAT PRODUCTS USING AMES TEST

The use of food additives must be under control specially with the improvement of many diseases such as cancer disease which became the most threaten disease all over the world, although there had become more health aware and medical culture, many unhealthy food products are being consumed increasely, so it became very important to study some food product’s mutagenicity. Detecting mutagenicity with short term assay with high percentage sensitivity are specifications available at Ames test with the mutated Salmonella typhimiurium strains and the reverse growth of the mutated bacteria was an indicator to the sample tested mutagenicity .The aim of this study is to evaluate the effect of adding sodium nitrite salt with various levels on mutagenicity in two of processed meat products (pastirma and luncheon) using Ames test. The results gave in the tested samples sign of mutagenicity at low concentrations and high reverse growth at higher concentrations , sodium nitrite extract gave highest mutagenicity at 10% (1.5 ml dose ) concentration , pastirma extract gave highest mutagenicity at 10% concentration (2 ml dose ) and luncheon extract gave highest mutagenicity at 100% concentration.

Color development, physiochemical properties, and microbiological safety of pork jerky processed with atmospheric pressure plasma

Abstract We investigated the applicability of atmospheric pressure plasma (APP) as an alternative to sodium nitrite in pork jerky manufacturing. Pork slices were marinated in brine with no sodium nitrite at 4 °C for 16 h and treated by APP for 0, 20, 40, and 60 min, respectively. The sample marinated in the brine with sodium nitrite (100 ppm) was also prepared. Then, all samples were dried. As APP treatment time increased, the a⁎ value (redness), nitrosoheme pigment content, and residual nitrite content increased, while lipid oxidation decreased (all P Industrial relevance The global interest in sodium nitrite substitute for meat products manufacturing has considerably grown for years because consumer's demand of foods labeled “natural” and “chemical-free” has been increasing. In general, APP is recognized as a novel non-thermal food processing technology that uses energetic, reactive species to inactivate microbes on various foods. Recently, meat curing system involving direct APP treatment was proposed. The present study tried to apply APP to manufacturing pork jerky without using sodium nitrite. As a result, similar quality properties, particularly color, were observed in jerky applied by APP compared to jerky made with sodium nitrite. Application of APP also improved the microbiological safety of pork jerky. Therefore, APP can be applied for manufacturing potentially safer pork jerky by inactivation of heat-resistant pathogens without added sodium nitrite.

Nitrocobinamide, a new cyanide antidote that can be administered by intramuscular injection.

Currently available cyanide antidotes must be given by intravenous injection over 5-10 min, making them ill-suited for treating many people in the field, as could occur in a major fire, an industrial accident, or a terrorist attack. These scenarios call for a drug that can be given quickly, e.g., by intramuscular injection. We have shown that aquohydroxocobinamide is a potent cyanide antidote in animal models of cyanide poisoning, but it is unstable in solution and poorly absorbed after intramuscular injection. Here we show that adding sodium nitrite to cobinamide yields a stable derivative (referred to as nitrocobinamide) that rescues cyanide-poisoned mice and rabbits when given by intramuscular injection. We also show that the efficacy of nitrocobinamide is markedly enhanced by coadministering sodium thiosulfate (reducing the total injected volume), and we calculate that ∼1.4 mL each of nitrocobinamide and sodium thiosulfate should rescue a human from a lethal cyanide exposure.

The significant blood resistance to lung nitric oxide transfer lies within the red cell

The lung nitric oxide (NO) diffusing capacity (DlNO) mainly reflects alveolar-capillary membrane conductance (Dm). However, blood resistance has been shown in vitro and in vivo. To explore whether this resistance lies in the plasma, the red blood cell (RBC) membrane, or in the RBC interior, we measured the NO diffusing capacity (Dno) in a membrane oxygenator circuit containing ∼1 liter of horse or human blood exposed to 14 parts per million NO under physiological conditions on 7 separate days. We compared results across a 1,000-fold change in extracellular diffusivity using dextrans, plasma, and physiological salt solution. We halved RBC surface area by comparing horse and human RBCs. We altered the diffusive resistance of the RBC interior by adding sodium nitrite converting oxyhemoglobin to methemoglobin. Neither increased viscosity nor reduced RBC size reduced Dno. Adding sodium nitrite increased methemoglobin and was associated with a steady fall in Dno (P < 0.001). Similar results were obtained at NO concentrations found in vivo. The RBC interior appears to be the site of the blood resistance.