Blood Methemoglobin Research Articles

Dietary nitrate and presence of protozoa increase nitrate and nitrite reduction in the rumen of sheep.

Nitrate ( ) supplementation is an effective methane (CH4 ) mitigation strategy for ruminants but may produce nitrite ( ) toxicity. It has been reported that rumen protozoa have greater ability for and reduction than bacteria. It was hypothesised that the absence of ruminal protozoa in sheep may lead to higher accumulation in the rumen and a higher blood methaemoglobin (MetHb) concentration. An in vivo experiment was conducted with defaunated (DEF) and faunated (FAU) sheep supplemented with 1.8% in DM. The effects of rumen protozoa on concentrations of plasma and ruminal and , blood MetHb, ruminal volatile fatty acid (VFA) and ruminal ammonia (NH3 ) were investigated. Subsequently, two in vitro experiments were conducted to determine the contribution of protozoa to and reduction rates in DEF and FAU whole rumen digesta (WRD) and its liquid (LIQ) and solid (SOL) fractions, incubated alone (CON), with the addition of or with the addition of . The results from the in vivo experiment showed no differences in total VFA concentrations, although ruminal NH3 was greater (p<.01) in FAU sheep. Ruminal , and plasma concentrations tended to increase (p<.10) 1.5hr after feeding in FAU relative to DEF sheep. In vitro results showed that reduction to NH3 was stimulated (p<.01) by incoming in both DEF and FAU relative to CON digesta. However, adding increased (p<.05) the rate of accumulation in the SOL fraction of DEF relative to both fractions of FAU digesta. Results observed in vivo and in vitro suggest that and are more rapidly metabolised in the presence of rumen protozoa. Defaunated sheep may have an increased risk of poisoning due to accumulation in the rumen.

Comparative effectiveness of means to reduce negative effects of lead, cadmium and nitrates

According to the constant deterioration of the environmental situation, the issue of preserving health of agricultural animals and obtaining safe livestock products is acute. One of the most effective ways to reduce the accumulation and ecotoxicants impact is pharmacological drugs usage and feed additives with different mechanisms of action. A comparative assessment of various agents exposed to heavy metals and nitrates in laboratory animals is presented. It was found that using feed with an increased content of heavy metals and nitrates increased the level of ecotoxicants in the organs and tissues of animals. Solvimin selenium enabled to reduce the accumulation of cadmium and lead in organism (up to 45 %), restore the normal amount of hemoglobin and the summation threshold, animals’ weight, protein and carbohydrate metabolism. However, it did not restore the indicators of the liver and kidneys functional state. The use of laricarvit showed a fairly high protective efficiency in removing cadmium (25– 30 %) and reducing the nitrates accumulation in the blood and muscles, normalizing the body weight of animals, the number of white blood cells, lymphocytes and methemoglobin. Detox injections successfully reduced the content of nitric nitrogen in the blood, in the liver and, to some extent, in the kidneys, while complete normalization of blood parameters was not observed.

Nitrate Poisoning due to Ingestion of Cabbages (Brassica oleracea var. capitata L.) (Brassicaceae) in Kitui County, Kenya.

Nitrate toxicosis associated with consumption of cabbages (Brassica oleracea var. capitata L.) (Brassicaceae) was diagnosed in a small herd comprising of ten goats in Matinyani ward, Kitui West sub-County of Kitui County in Kenya. The clinical signs were ataxia, ruminal tympany, bluish-brown mucous membranes, rapid and difficult breathing, incoordination, head pressing, aggressive movements, jugular distension, increased heart rates, tremors, and coma. Six goats died of intoxication. Dark brown/chocolate-colored and poorly clotted blood was the prominent necropsy finding. There was limited froth in the trachea and bronchi consistent with mild pulmonary oedema. There were liver congestion, pericarditis, and enlarged and congested kidneys with pinpoint haemorrhages. Four other affected goats were treated with intramuscular antihistamines and oral administration of ivermectin. No further mortality was observed after the treatment. Cabbages fed to goats had 6.6% nitrate on dry matter (DM) basis , while ruminal contents had 5.55% nitrate on dry matter basis (DM). Dark brown blood collected at postmortem had a methemoglobin fraction of 78%. Forage nitrate levels of 0.5% and above are potentially dangerous, with acute poisoning likely to occur if the nitrate level exceeds 1%. Death can occur when blood methemoglobin levels rise up to 67–90%. Findings from the current study are indicative of nitrate-nitrite toxidrome associated with ingestion of cabbages.

Blood optical absorption of rats with hepatic damage and turmeric treatment: Methemoglobin analysis

Photoacoustic spectroscopy (PAS) is singled out by its capability to resolve the optical absorption spectra of each element, of a multicomponent system, by the named phase resolved method. The possibility of the use of this method is due to the fact that the Photoacoustic signal is not only sensitive to the optical absorption of the sample as well as the non-radiative relaxation times of its elements. In the present study we compare and analyze, by phase resolved method, Fisher rat blood in four groups: healthy rat blood, liver cancer rat blood, healthy rat blood given by a daily dose of Curcuma longa, and liver cancer rat blood given by a daily dose of Curcuma longa (turmeric), where the optical absorption spectra of the analyzed blood samples was obtained by PAS, in a wavelength range from 350 nm to 650 nm. Three repetitions of 60 μl of blood for each group was done. By using the phase resolved method a new optical absorption band suggestive of methemoglobin was found, observing the benefits of the intake of turmeric due to the fact that the optical absorption spectrum of the Cancer + turmeric group diminish 14% with respect to the Cancer group, anticipating a lower concentration of methemoglobin in blood.

Potential roles of nitrate and live yeast culture in suppressing methane emission and influencing ruminal fermentation, digestibility, and milk production in lactating Jersey cows

Concern over the carbon footprint of the dairy industry has led to various dietary approaches to mitigate enteric CH4 production. One approach is feeding the electron acceptor NO3-, thus outcompeting methanogens for aqueous H2. We hypothesized that a live yeast culture (LYC; Saccharomyces cerevisiae from Yea-Sacc 1026, Alltech Inc., Nicholasville, KY) would stimulate the complete reduction of NO3- to NH3 by selenomonads, thus decreasing the quantity of CH4 emissions per unit of energy-corrected milk production while decreasing blood methemoglobin concentration resulting from the absorbed intermediate, NO2-. Twelve lactating Jersey cows (8 multiparous and noncannulated; 4 primiparous and ruminally cannulated) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Cattle were fed diets containing 1.5% NO3- (from calcium ammonium nitrate) or an isonitrogenous control diet (containing additional urea) and given a top-dress of ground corn without or with LYC, with the fourth week used for data collection. Noncannulated cows were spot measured for CH4 emission by mouth using GreenFeed (C-Lock Inc., Rapid City, SD). The main effect of NO3- decreased CH4 by 17% but decreased dry matter intake by 10% (from 19.8 to 17.8 kg/d) such that CH4:dry matter intake numerically decreased by 8% and CH4:milk net energy for lactation production was unaffected by treatment. Milk and milk fat production were not affected, but NO3- decreased milk protein from 758 to 689 g/d. Ruminal pH decreased more sharply after feeding for cows fed diets without NO3-. Acetate:propionate was greater for cows fed NO3-, particularly when combined with LYC (interaction effect). Blood methemoglobin was higher for cattle fed NO3- than for those fed the control diet but was low for both treatments (1.5 vs. 0.5%, respectively; only one measurement exceeded 5%), indicating minimal risk for NO2- accumulation at our feeding level of NO3-. Although neither apparent organic matter nor neutral detergent fiber digestibilities were affected, apparent N digestibility had an interaction for NO3- × LYC such that apparent N digestibility was numerically lowest for diets containing both NO3- and LYC compared with the other 3 diets. Under the conditions of this study, NO3- mitigated ruminal methanogenesis but also depressed dry matter intake and milk protein yield. Based on the fact that few interactions were detected, LYC had a minimal role in attenuating negative cow responses to NO3- supplementation.

Gasometric gradients between blood obtained from the pulmonary artery wedge and pulmonary artery positions in pulmonary arterial hypertension

IntroductionLittle is known on the pulmonary gradients of oxyhemoglobin, carboxyhemoglobin and methemoglobin in pulmonary arterial hypertension (PAH). We sought to determine these gradients in group 1 PAH and assess their association with disease severity and survival.MethodsDuring right heart catheterization (RHC) we obtained blood from pulmonary artery (PA) and pulmonary artery wedge (PAW) positions and used co-oximetry to test their gasometric differences.ResultsWe included a total of 130 patients, 65 had group 1 PAH, 40 had pulmonary hypertension (PH) from groups 2–5 and 25 had no PH during RHC. In all groups, PAW blood had higher pH, carboxyhemoglobin and lactate as well as lower pCO2 than PA blood. In group 1 PAH (age 58 ± 15 years, 72% females), methemoglobin in the PAW was lower than in the PA blood (0.83% ± 0.43 vs 0.95% ± 0.50, p = 0.03) and was directly associated with the degree of change in pulmonary vascular resistance (R = 0.35, p = 0.02) during inhaled nitric oxide test. Oxyhemoglobin in PA (HR (95%CI): 0.90 (0.82–0.99), p = 0.04) and PAW (HR (95%CI): 0.91 (0.84–0.98), p = 0.003) blood was associated with adjusted survival in PAH.ConclusionsMarked differences were observed in the gasometric determinations between PAW and PA blood. The pulmonary gradient of methemoglobin was lower in PAH patients compared to controls and a higher PAW blood methemoglobin was associated with a more pronounced pulmonary vascular response to inhaled nitric oxide. Pulmonary artery and PAW oxyhemoglobin tracked with disease severity and survival in PAH.

Effect of Zamzam water on blood methemoglobin level in young rats.

BACKGROUND:Methemoglobin (MetHb) level in blood indicates exposure to nitrogenous compounds. Acquired methemoglobinemia as a result of exposure to nitrates in drinking water is primarily an issue for infants. The amount of nitrates in Zamzam water is said to be on the high side. This study was designed to determine the effect of prolonged use of Zamzam water on MetHb in rat pups.MATERIALS AND METHODS:Wistar rat pups (n = 52, 3 weeks old) were divided into four equal groups. All of them were given normal laboratory chow. The groups differed only in the exclusive source of water, that is ordinary bottled water, standardized mineral water, old Zamzam water (stored since 2008) or fresh Zamzam water. MetHb level was checked (using Avoximeter 4000) at the baseline, and then every week for 4 weeks from blood obtained from retro-orbital sinus. Other parameters tested were total haemoglobin, oxyhemoglobin and carboxyhemoglobin. ANOVA was used to compare the means between the groups.RESULTS:None of the rats in any of the four groups showed any sign of methemoglobinemia or toxicity. Both groups on Zamzam water showed higher increments in their total hemoglobin by the end of the study compared to their baseline (22%) than the ordinary water (9%) and the mineral water (5%) groups. None of the groups showed any significant difference in MetHb levels on intergroup comparison at any of the weekly readings and at the end of the study.CONCLUSION:Prolonged use of Zamzam water did not induce any significant difference in MetHb concentration in rat pups, which might indicate that it is safe for infants.

Morphological blood indices of bulls in experimental chronic cadmium toxico-sis

The article presents the results of research on the influence of cadmium load on the body of young cattle. The purpose of the work was to investigate morphological indices of bulls blood during the development of experimental chronic cadmium toxicity. According to the morphological analysis of the quantitative and qualitative composition of blood, it is possible to deem objectively about the functional state of the hematopoietic system of the organism of young cattle. The research was conducted (on the basis of the farm of the village of Ivanivtsi, Zhydachiv rayon of the Lviv region) on 10 bulls of six months old, Ukrainian black-and-white milk breed, which were formed in 2 groups of 5 animals in each: control and experimental. Bulls of the control group were in the usual diet. Bulls of the experimental group were fed with a feed with cadmium chloride at a dose of 0.04 mg/kg body weight of the animal. It has been established that feeding Bulls with cadmium chloride in a dose of 0.04 mg/kg of body weight contributed to a decrease in hemoglobin to 84.5 ± 1.60 g/l and an increase in the content of methemoglobin to 5.2 ± 0.099%. The decrease in hemoglobin levels is due to the toxic effect of cadmium on erythrocytes, resulting in damage to erythrocyte membranes and increased content of methemoglobin. Formation of methemoglobin in bull blood during cadmium loading occurs as a result of oxidation of hemoglobin with the formation of superoxide anion, which in turn triggers (begins) free radical processes and exerts a destructive effect on cell membranes, as well as initiates the appearance of other active forms of oxygen. Feeding calcium cadmium chloride in a dose of 0.04 mg/kg contributed to a decrease in the number of erythrocytes in their blood. At day 20 of the experiment, the number of erythrocytes decreased by 14% relative to the control group. Decreasing the number of erythrocytes in the blood of young cattle may have been due to the inhibition of their production in the bone marrow. An important morphological indicator of blood is the determination of the average content of hemoglobin in one erythrocyte, which indicates the saturation of erythrocyte with hemoglobin. It was found that the average hemoglobin content in one erythrocyte of the bulls of the experimental group increased by 11.4 and 13.9% for 5 and 10 days. According to the results of the research, the reduction of the hematocrit values in the experimental group of bulls was detected at 10, 15 and 20 days of the experiment. A significant increase in the number of leukocytes in the blood of the bulls of the experimental group was observed at 15 days of the experiment, according to the control group indicators, it increased by 12%.

Therapeutic effect of ascorbic acid on dapsone-induced methemoglobinemia in rats.

ObjectiveDapsone (diaminodiphenyl sulfone, DDS) is currently used to treat leprosy, malaria, dermatitis herpetiformis, and other diseases. It is also used to treat pneumocystis pneumonia and Toxoplasma gondii infection in HIV-positive patients. The most common adverse effect of DDS is methemoglobinemia from oxidative stress. Ascorbic acid is an antioxidant and reducing agent that scavenges the free radicals produced by oxidative stress. The present study aimed to investigate the effect of ascorbic acid in the treatment of DDS induced methemoglobinemia.MethodsMale Sprague-Dawley rats were divided into three groups: an ascorbic acid group, a methylene blue (MB) group, and a control group. After DDS (40 mg/kg) treatment via oral gavage, ascorbic acid (15 mg/kg), MB (1 mg/kg), or normal saline were administered via tail vein injection. Depending on the duration of the DDS treatment, blood methemoglobin levels, as well as the nitric oxide levels and catalase activity, were measured at 60, 120, or 180 minutes after DDS administration.ResultsMethemoglobin concentrations in the ascorbic acid and MB groups were significantly lower compared to those in the control group across multiple time points. The plasma nitric oxide levels and catalase activity were not different among the groups or time points.ConclusionIntravenous ascorbic acid administration is effective in treating DDS-induced methemoglobinemia in a murine model.

Lokal anestezik (prilokain) uygulamasına bağlı gelişen methemoglobinemi: Olgu sunumu

Introduction: Circumcision is a surgical procedure performed by many societies for religious, medical and cultural purposes. One of the agents used during this procedure is prilocaine, a commonly used local anesthetic. In the literature, cases of methemoglobinemia which can be developed with the application of prilocaine in normal dose have been reported. Oxidation of hemoglobin with various oxidative stresses is called methemoglobinemia when the divalent iron in its content is converted into its trivalent form. This reaction leads to hypoxaemia in the tissue and a clinical picture of cyanosis occurs at varying degrees.Case Report: Two-and-a-half-month-old patient was referred to my hospital by a physician because of the complaint of bruising after local anesthesia with prilocaine and the measured oxygen saturation was 79%. Physical examination revealed cyanosis in the peroral region, hands and feet. It was decided that methylene blue should be administered considering the fact that the patient was given prilocaine as a local anesthetic, due to the inability to find an underlying respiratory and cardiac cause, and because of the high value of methemoglobin in blood gas. Methylene blue 2 mg/kg was given orally. About an hour later, cyanosis disappeared. The control methhemoglobin level was found to be 2.7%. Conclusion: Methemoglobinemia should be considered in the differential diagnosis of cyanosis after local anesthetic application and local anesthetics with less side effects should be preferred in early infancy. In this case report, it was aimed to discuss the differential diagnosis and treatment methods of methemoglobinemia after local anesthesia with prilocaine.

Динаміка змін фізіологічного стану і гематологічних показників райдужної форелі під час запуску біофільтра в установках замкненого водовикористання

Наведено результати змін фізіологічного стану і гематологічних показників райдужної форелі у воді установок замкненого водопостачання. Показано, що під час запуску біофільтра УЗВ найбільша загибель малька райдужної форелі виникає з 16 по 20 добу досліду і становить 14,9% від усієї риби. При цьому вся жива риба плавала у верхніх шарах води, у ≈ 50% риби спостерігалося нервове тремтіння тіла та плавників, вона масово підпливала до місця подавання води, у ≈ 90% риби ввідмічали потемніння тіла і плавників, які були ущільнені, у ≈ 90% риби колір зябер змінювався з червоного на коричневий.З моменту запуску біофільтра і до 25 доби у крові риби знижувалася кількість еритроцитів, яка виявилася вірогідною у період з 16 по 20 добу (Р ≤ 0,05) і з 21 по 25 добу, а також вірогідно знижувався рівень гемоглобіну на 16–20 і 21–25 доби (Р ≤ 0,05).Із запуском біофільтра в присутності малька райдужної форелі у крові риб, порівняно із початком запуску біофільтра, зростає вміст метгемоглобіну: на 6–10 добу досліду на 8,8%, 11–15 добу – на 15,0%, 16–20 добу – на 26,4%, 21–25 добу – на 16,8%, 26–30 добу – на 12,8% і 31–35 добу – на 2,1%.

Feasibility and preliminary safety of nitric oxide releasing solution as a treatment for bovine mastitis

Nitric oxide-releasing solution (NORS) is a liquid formulation that releases nitric oxide, a broad spectrum antimicrobial, single electron nitroxide radical. This solution was investigated as a potential antimicrobial treatment for bovine mastitis (BM). Three experiments were performed: a) NORS' effect on Staphylococcus aureus and Escherichia coli in an in vitro model; b) NORS' effect on milk obtained from dairy cows showing symptoms of clinical mastitis; and c) the consequences of administering NORS to healthy milking cattle using a dose-escalating in vivo study. Metabolite concentrations were estimated in their blood for methaemoglobin and nitrite; also, milk nitrite concentration and somatic cell count (SCC) were measured to study possible mammary gland inflammation following treatment. NORS lowered the bacterial concentration in all infected samples, in a time- and milk-diluted dependant fashion. Blood methemoglobin concentrations following treatment were all within the normal range for cattle. However, blood and milk nitrite concentrations increased initially but, during the next 24 h, returned to normal range, as did SCC, without any clinical signs of mammary gland inflammation. NORS, if shown to be effective, could be an alternative treatment for mastitis with a shorter clearance time.

Rejyonal İntravenöz Anestezi ve Aksiller Blok ile Üst Ekstremite Cerrahi Operasyonu Geçirecek Hastalarda Kan Methemoglobin Düzeyinin Karşılaştırılması

Rejyonal İntravenöz Anestezi ve Aksiller Blok ile Üst Ekstremite Cerrahi Operasyonu Geçirecek Hastalarda Kan Methemoglobin Düzeyinin Karşılaştırılması

Nitrate poisoning in ruminants

This paper describes the nitrate - nitrite poisoning of ruminants. This disease is caused by the ingestion of large amount of nitrate salts, which are reduced in the rumen to nitrite ions. Nitrites, after their absorption, cause the formation of methemoglobin and, in turn, respiratory and circulatory distress. The aim of the treatment is to reduce the percentage of methemoglobin in blood and to stop the continuing production of nitrite ions in the rumen. For the prevention of the disease, avoidance of feedstuff rich in nitrates and improvement of the water quality, are suggested.

Nitrate induces a type 1 diabetic profile in alligator hatchlings

Type 1 diabetes (T1D) is a chronic autoimmune disease that affects 1 in 300 children by age 18. T1D is caused by inflammation-induced loss of insulin-producing pancreatic beta cells, leading to high blood glucose and a host of downstream complications. Although multiple genes are associated with T1D risk, only 5% of genetically susceptible individuals actually develop clinical disease. Moreover, a growing number of T1D cases occur in geographic clusters and among children with low risk genotypes. These observations suggest that environmental factors contribute to T1D etiology. One potential factor, supported primarily by epidemiological studies, is the presence of nitrate and nitrite in drinking water. To test this hypothesis, female hatchling alligators were exposed to environmentally relevant concentrations of nitrate in their tank water (reference, 10mg/L, or 100mg/L NO3-N) from hatch through 5 weeks or 5 months of age. At each time point, endpoints related to T1D were investigated: plasma levels of glucose, triglycerides, testosterone, estradiol, and thyroxine; pancreas, fat body, and thyroid weights; weight gain or loss; presence of immune cells in the pancreas; and pancreatic beta cell number, assessed by antibody staining of nkx6.1 protein. Internal dosing of nitrate was confirmed by measuring plasma and urine nitrate levels and whole blood methemoglobin. Cluster analysis indicated that high nitrate exposure (most animals exposed to 100mg/L NO3-N and one alligator exposed to 10mg/L NO3-N) induced a profile of endpoints consistent with early T1D that could be detected after 5 weeks and was more strongly present after 5 months. Our study supports epidemiological data correlating elevated nitrate with T1D onset in humans, and highlights nitrate as a possible environmental contributor to the etiology of T1D, possibly through its role as a nitric oxide precursor.

568 Effects of encapsulated nitrate on growth performance, nitrate toxicity, and enteric methane emissions in feedlot beef steers: Backgrounding phase

A backgrounding feedlot study was conducted to examine the effects of feeding encapsulated calcium ammonium nitrate (EN) on growth, enteric methane production, and nitrate (NO3-) toxicity in beef cattle. A total of 108 crossbred steers (292 ± 18 kg) were blocked by BW and randomly assigned to 18 pens. The pens (experimental unit; 6 animals per pen) received 3 dietary treatments: Control, a backgrounding diet supplemented with urea (0.2% NO3-and 0.9% urea in dietary DM); 1.25% EN, control diet supplemented with 1.25% EN (1.2% NO3-) in dietary DM, which partially replaced urea; or 2.5% EN, control diet supplemented with 2.5% EN (2.3% NO3-) in dietary DM, fully replacing urea. Twenty four steers were allocated to additional 4 pens and randomly assigned to 1 of the above 3 dietary treatments plus a fourth treatment: 2.3% UEN, control diet supplemented with 2.3% unencapsulated NO3-(UEN; 2.4% NO3-) fully replacing urea. Animals in the additional 4 pens were used for methane measurement in respiratory chambers and the pens (except UEN) were also part of the performance study (i.e., n = 7 pens/treatment). The experiment was conducted for 91 d in a randomized complete block design. During the experiment, DMI was not affected by inclusion of EN in the diet. Changes in BW, ADG, and gain:feed were not observed (P 0.57) by feeding EN. Methane production (g/d) tended to decrease (P= 0.099) by NO3-(188, 174, 156, and 152 g/d for Control, 1.25%, 2.5% EN, and UEN, respectively), but yield (g/kg DMI) did not differ (P= 0.56) among treatments. Inclusion of EN in the diet increased (P 0.02) sorting of the diets in favor of large and medium particles and against small and fine particles resulting in considerable increases in NO3-concentrations of orts without affecting DMI. Plasma NO3-and NO2-concentrations increased (P 0.05) for EN compared with Control in a dose response manner, but blood methemoglobin levels were below the detection limit. Nitrate concentration in fecal samples slightly increased (from 0.01% to 0.14%;P<0.01) with increasing levels of EN in the diet. In conclusion, EN can be used as a feed additive replacing urea in beef cattle diets during the backgrounding phase without NO3-intoxication or any negative effects on growth performance. In addition, the study confirmed that feeding EN tended to decrease enteric methane production in the long term.

Effects of encapsulated nitrate on growth performance, carcass characteristics, nitrate residues in tissues, and enteric methane emissions in beef steers: Finishing phase.

A finishing feedlot study was conducted with beef steers to determine effects of encapsulated nitrate (EN) on growth performance, carcass characteristics, methane production, and nitrate (NO) residues in tissues. The 132 crossbred steers were backgrounded in a feedlot for 91 d and transitioned for 28 days to the high-concentrate diets evaluated in the present study, maintaining the treatment and pen assignments designated at the start of the backgrounding period. The steers were initially assigned to 22 pens (6 animals per pen) in a randomized complete block design with BW (18 pens) and animals designated for methane measurement (4 pens) as blocking factors. Five animals in each pen designated for methane measurement (total of 20 animals) were monitored for methane emissions in respiratory chambers twice during the experiment. Pens received 3 dietary treatments (7 pens each): Control, a finishing diet supplemented with urea; 1.25% EN, control diet supplemented with 1.25% encapsulated NO in dietary DM that partially replaced urea; and 2.5% EN, control diet supplemented with 2.5% EN (DM basis) fully replacing urea. The final pen designated only for methane measurement received a fourth dietary treatment, 2.3% UEN, the control diet supplemented with unencapsulated NO (UEN) fully replacing urea. The cattle weighed 449 ± SD 32 kg at the start of the 150-d finishing period. The 2.5% EN diet decreased ( < 0.01) DMI compared with Control and 1.25% EN diets. Feeding EN tended to increase ( = 0.092) ADG compared with Control, and G:F was improved ( < 0.01) for EN compared with Control. No differences in methane production (g/d) and yield (g/kg DMI) were observed among treatments. Inclusion of EN in the diets increased ( ≤ 0.03) sorting in favor of large and medium particles and against small and fine particles. Plasma NO and NO concentrations were elevated ( < 0.01) with EN in a dose-response manner, but total blood methemoglobin levels for all treatments were low, below the detection limit. Feeding EN increased ( < 0.01) NO concentrations of samples from muscle, fat, liver, and kidney; NO concentrations of these tissues were similar between 1.25% EN and 2.3% UEN. In conclusion, inclusion of 2.5% EN in a finishing diet (DM basis; about 2% NO) did not cause NO toxicity or any health problems in the long term. In comparison with supplemental urea, feeding EN improved feed efficiency despite increases in sorting against dietary EN.

Effects of encapsulated nitrate on growth performance, nitrate toxicity, and enteric methane emissions in beef steers: Backgrounding phase.

A long-term experiment was conducted to examine the effects of feeding encapsulated nitrate (EN) on growth, enteric methane production, and nitrate (NO) toxicity in beef cattle fed a backgrounding diet. A total of 108 crossbred steers (292 ± 18 kg) were blocked by BW and randomly assigned to 18 pens. The pens (experimental unit; 6 animals per pen) received 3 dietary treatments: Control, a backgrounding diet supplemented with urea; 1.25% EN, control diet supplemented with 1.25% encapsulated calcium ammonium NO (i.e., EN) in dietary DM, which partially replaced urea; or 2.5% EN, control diet supplemented with 2.5% EN (DM basis) fully replacing urea. Additionally, 24 steers were located in 4 pens and randomly assigned to 1 of the above 3 dietary treatments plus a fourth treatment: 2.3% UEN, control diet supplemented with 2.3% unencapsulated calcium ammonium NO (UEN) fully replacing urea. Animals in the additional 4 pens were used for methane measurement in respiratory chambers, and the pens (except UEN) were also part of the performance study (i.e., = 7 pens/treatment). The experiment was conducted for 91 d in a randomized complete block design. During the experiment, DMI was not affected by inclusion of EN in the diet. Feeding EN had no effect on BW, ADG, and G:F ( ≥ 0.57). Methane production (g/d) tended to decrease ( = 0.099) with EN and UEN, but yield (g/kg DMI) did not differ ( = 0.56) among treatments. Inclusion of EN in the diet increased ( ≤ 0.02) sorting of the diets in favor of large and medium particles and against small and fine particles, resulting in considerable increases in NO concentrations of orts without affecting DMI. Plasma NO-N and NO-N concentrations increased ( ≤ 0.05) for EN compared with Control in a dose response manner, but blood methemoglobin levels were below the detection limit. Nitrate concentration in fecal samples slightly increased (from 0.01% to 0.14% DM; < 0.01) with increasing levels of EN in the diet. In conclusion, EN can be used as a feed additive replacing urea in beef cattle during a backgrounding phase in the long term without NO intoxication or any negative effects on growth performance. In addition, the study confirmed that feeding EN tended to decrease enteric methane production in the long term.

Three-wavelength method for the optical differentiation of methemoglobin and sulfhemoglobin in oxygenated blood.

Methemoglobinemia and sulfhemoglobinemia are rare, but potentially life threatening, diseases that refer to an abnormal amount of methemoglobin or sulfhemoglobin in the blood, respectively. Unfortunately, blood samples containing abnormal quantities of methemoglobin or sulfhemoglobin have similar spectral characteristics. This makes it difficult to optically differentiate them and, hence, difficult to diagnose a patient with either disease. However, performing treatments for one of the diseases without a correct diagnosis can introduce increased risk to the patient. In this paper, we propose a method for differentiating the presence of methemoglobin and sulfhemoglobin in blood, under several conditions, using reflectance values measured at three wavelengths. In order to validate our method, we perform in silico experiments considering various levels of methemoglobin and sulfhemoglobin. These experiments employ a cell-based light interaction model, known as CLBlood, which accounts for the orientation and distribution of red blood cells. We then discuss the reflectance curves produced by the experiments and evaluate the efficacy of our method. In particular, we consider various experimental conditions by modifying the flow rate, hemolysis level and incident light direction.

The novel nitric oxide donor PDNO attenuates ovine ischemia-reperfusion induced renal failure

BackgroundRenal ischemia-reperfusion injury is a common cause of acute kidney injury in intensive care and surgery. Recently, novel organic mononitrites of 1,2-propanediol (PDNO) were synthesized and shown to rapidly and controllably deploy nitric oxide in the circulation when administered intravenously. We hypothesized that intravenous infusion of PDNO during renal ischemia reperfusion would improve post-ischemic renal function and microcirculation.MethodsSixteen sheep were anesthetized, mechanically ventilated, and surgically instrumented. The left renal artery was clamped for 90 min, and the effects of ischemia were studied for a total of 8 h. Fifteen minutes prior to the release of the clamp, intravenous infusions of PDNO (n = 8) or vehicle (1,2 propanediol + inorganic nitrite, n = 8) were initiated (180 nmol/kg/min for 30 min, thereafter 60 nmol/kg/min for the remainder of the experiment).ResultsRenal artery blood flow, cortical and medullary perfusion, and diuresis and creatinine clearance decreased in the left kidney post ischemia. However, in the sheep treated with PDNO, diuresis and creatinine clearance in the left kidney were significantly higher post ischemia compared to vehicle-treated animals (1.7 ± 0.5 vs 0.7 ± 0.3 ml/kg/h, p = 0.04 and 7.5 ± 2.1 vs 1.7 ± 0.6 ml/min, p = 0.02, respectively). Left renal medullary perfusion and oxygen uptake were higher in the PDNO group (73 ± 9 vs 37 ± 5% of baseline, p = 0.004 and 2.6 ± 0.4 vs 1.6 ± 0.3 ml/min, p = 0.02, respectively). PDNO significantly increased renal oxygen consumption and reduced the oxygen utilization for sodium reabsorption (p = 0.03 for both). Mean arterial blood pressure was significantly reduced by PDNO (83 ± 3 vs 94 ± 3 mmHg, p = 0.02) but was still within normal limits. Total renal blood flow was not affected, and there were no signs of increased blood methemoglobin concentrations or tachyphylaxis.ConclusionsThe novel nitric oxide donor PDNO improved renal function after ischemia. PDNO also prevented the persistent reduction in medullary perfusion during reperfusion and improved renal oxygen utilization without severe side effects.