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PubMed1982

[Effect of nitrates, nitrate-like substances, calcium antagonists and beta-adrenergic receptor blockers on peripheral circulation].

The effectiveness of organic nitrates in the therapy of angina pectoris can be explained from their direct relaxing action on vascular smooth muscle. At conventional dosage the most important action of nitrates is a pooling of blood in the large systemic venous capacitance vessels which leads to a decrease of central venous pressure and ventricular filling pressure. The resulting reduction in left ventricular volume lowers, at virtually constant arterial pressure, systolic wall tension and hence myocardial oxygen consumption. Only at higher dosage, is a distinct dilatation of systemic resistance vessels affected. The fundamental action of the "Ca antagonists", i.e. the inhibition of transmembrane calcium influx in the myocardium and the vascular smooth muscle, includes various beneficial effects for the treatment of angina pectoris. The lowering of myocardial oxygen consumption after application of calcium antagonist is mainly due 1. to the decrease in afterload of the left ventricle, caused by the relaxation of peripheral resistance vessels, 2. to the reduction in ventricular preload by a peripheral venodilation. By a direct inhibitory effect on the coronary vascular tone, coronary blood flow at rest in patients with angina pectoris increases. In addition, Ca antagonists are very efficacious in relieving angiospastic angina. The primary mode of action of beta-blocking drugs in angina pectoris affects, in contrast to the peripheral mechanisms of nitrates and Ca antagonists, is on the heart directly. By the reduction in the extent of exercise heart rate, the increase in cardiac output and, hence, the mean arterial pressure is also significantly lower during exercise under beta-blockade. Beta-blockers also depress the contractile state of myocardium. Therefore, the main factors of the myocardial oxygen consumption (mean arterial pressure, size of the left ventricle, contractility and heart rate) may be essentially influenced. By the decrease in heart rate and the longer diastolic period a better myocardial oxygen delivery results. Besides the immediate cardiac effects of beta-adrenergic blockade, a decline in peripheral resistance combined with a fall in blood pressure occur in hypertensive patients during long-term drug administration. Different hypotheses have been proposed in the last years to explain the antihypertensive mode of action of beta-blockers. Some possible mechanisms are discussed.

Adrenergic beta-Antagonists↗
PubMed1995

Sample pretreatment with nitrate reductase and glucose-6-phosphate dehydrogenase quantitatively reduces nitrate while avoiding interference by NADP+ when the Griess reaction is used to assay for nitrite.

An assay for the simultaneous measurement of nitrite and nitrate, products of nitric oxide metabolism, is described. Others have reported pretreating sample by using nitrate reductase (NR) and NADPH to reduce endogenous NO3- before assaying the resultant NO2- using the Griess reaction. However, we found that the NADP+ formed during pretreatment interfered with the Griess reaction when NADPH was used at concentrations necessary to drive the NR reaction. For instance, 500 microM NADP+ in 100 microM NaNO3- (without NR) causes a 90% interference with the formation of Griess reaction product. To limit interference, we modified the method by decreasing the NADPH concentration to 1 microM. NADPH was regenerated by coupling the NR reaction with that catalyzed by glucose-6-phosphate dehydrogenase (GD). Using this method, NaNO3- standard curves were linear up to 100 microM and coincided with control curves obtained using NaNO2- incubated in parallel. Addition of urine up to a strength of 20% did not interfere with the assay. Comparison with an alternative assay based on cadmium reduction resulted in the following linear regression: [Cd method] = 0.915*[NR-GD method] + 0.37, r2 = 0.997. Coupling GD to NR to recycle NADPH allows this cofactor to be used at a low concentration so that interference with the Griess reaction is negligible.

Animals↗
PubMed1997

Stable Transformation of Chlorella: Rescue of Nitrate Reductase-Deficient Mutants with the Nitrate Reductase Gene

Unicellular green algae, like Chlorella, offer a potentially useful system for the expression of heterologous proteins. However, the development of Chlorella as a bioreactor has been delayed owing to the lack of a stable transformation technique. Here we report on the use of micro-projectile bombardment to introduce the nitrate reductase (NR) gene from Chlorella vulgaris into NR-deficient Chlorella sorokiniana mutants, resulting in stable transformants. The stable transformants were able to grow on nitrate medium after repeated passages between selective and nonselective medium and exhibited inducible nitrate reductase activity comparable to that of wild-type cells. Southern analysis suggests homologous recombination occurs with insertion of the wild type gene into the mutated gene and that the genes of the two Chlorellaspecies used are very similar. Specific RNase protection assays, selecting for a poorly conserved region of the gene, identified the presence of the C. vulgaris NR transcript only in the transformed C. sorkiniana mutant and not in the mutant.

Journal Article↗
PubMed1995

Intermittent transdermal nitrates do not improve ischemia in patients taking beta-blockers or calcium antagonists: potential role of rebound ischemia during the nitrate-free period.

OBJECTIVES: This study was conducted to determine whether rebound ischemia occurs during nitrate-free periods with intermittent cutaneous nitroglycerin therapy in patients with angina pectoris who are receiving background antianginal therapy. BACKGROUND: Rebound angina has been suggested to be a complication of the nitrate-free period with long-term cutaneous nitroglycerin therapy given intermittently to prevent tolerance. METHODS: Fifty-two patients with stable effort angina taking either a beta-adrenergic blocking agent (n = 25) or diltiazem (n = 22) or their combination (n = 5) completed a randomized, double-blind, placebo-controlled crossover study of cutaneous nitroglycerin patches (50 mg). Active or placebo patches were worn for 1 week, applied at 8 AM and removed at 10 PM to provide a 10-h daily nitrate-free (or placebo-free) period. During the last 48 h of each study phase, a Holter monitor was used to detect ischemia. RESULTS: Only 31 patients experienced ischemia during either phase of the study (23 during the patch-off period). A total of 463 ischemic episodes were recorded: 246 during placebo and 217 during nitroglycerin (p = 0.8, for per patient comparison). The majority (88%) of ischemic episodes were silent. Mean (+/- SEM) duration of ischemia during the total 48-h period was similar during active and placebo phases (35.5 +/- 15.0 min/24 h for active therapy vs. 29.7 +/- 9.8 for placebo, p = 0.8). This was due to an increase in duration of ischemia with active therapy during the patch-off period (46.9 +/- 17.9 min/24 h for active therapy vs. 22.5 +/- 9.2 for placebo, p = 0.07) and a decrease during the patch-on period (27.5 +/- 14.0 min/24 h for active therapy vs. 34.5 +/- 11.0 min/24 h for placebo, p = 0.16). The pattern of diurnal distribution of ischemic episodes differed between active and placebo phases. During placebo there was a nadir in the incidence of ischemia in the overnight patch-off period, with a significantly lower incidence between midnight and 6 AM (25 episodes) compared with the mean number of episodes during the three other 6-h periods (73 episodes, p < 0.001). During the nitroglycerin patch-off period, there was a loss of this overnight nadir, with the same incidence of ischemia between midnight and 6 AM (53 episodes) as the mean number of episodes for the three other 6-h periods (54 episodes). CONCLUSIONS: The majority of patients taking background antianginal therapy experienced no ischemia during the patch-off period. In the 44% of patients with ischemia during this period, there was a nonsignificant increase in the duration of ischemia with active therapy. Although this result was statistically inconclusive, the change in the distribution of diurnal ischemia offers suggestive evidence that rebound ischemia may be a problem with regard to intermittent cutaneous nitroglycerin.

Administration, Cutaneous↗
PubMed2002

Determination of the total oxygen isotopic composition of nitrate and the calibration of a delta 17O nitrate reference material.

A thermal decomposition method was developed and tested for the simultaneous determination of delta 18O and delta 17O in nitrate. The thermal decomposition of AgNO3 allows for the rapid and accurate determination of 18O/ 16O and 17O/16O isotopic ratios with a precision of +/- 1.5 per thousand for delta 18O and +/- 0.11 per thousand for delta 17O (delta 17O = delta 17O - 0.52 x delta 18O). The international nitrate isotope reference material IAEA-NO3 yielded a delta 18O value of +23.6 per thousand and delta 17O of -0.2 per thousand, consistent with normal terrestrial mass-dependent isotopic ratios. In contrast, a large sample of NaNO3 from the Atacama Desert, Chile, was found to have delta 17O = 21.56 +/- 0.11 per thousand and delta 18O = 54.9 +/- 1.5 per thousand, demonstrating a substantial mass-independent isotopic composition consistent with the proposed atmospheric origin of the desert nitrate. It is suggested that this sample (designated USGS-35) can be used to generate other gases (CO2, CO, N2O, O2) with the same delta 17O to serve as measurement references for a variety of applications involving mass-independent isotopic compositions in environmental studies.

Journal Article↗
PubMed2004

ipso-nitration of arylboronic acids with chlorotrimethylsilane-nitrate salts.

[reaction: see text] A mixture of nitrate salt and chlorotrimethylsilane is found to be an efficient regioselective nitrating agent for the ipso-nitration of arylboronic acids to produce the corresponding nitroarenes in moderate to excellent yields. High selectivity, simplicity, and convenience are the key features of the reaction.

Journal Article↗
PubMed2006

Synthesis, a case of isostructural packing, and antimicrobial activity of silver(I)quinoxaline nitrate, silver(I)(2,5-dimethylpyrazine) nitrate and two related silver aminopyridine compounds.

The synthesis and low temperature crystal structures of [Ag(quinoxaline)]n(NO3)n, 1, [Ag(2,5-dimethylpyrazine)(NO3)]n, 2 and [Ag4(3-aminopyridine)4(NO3)4]n 3 are presented. The quinoxaline compound forms a 1D coordination polymer with the characteristic linear 2-coordination figure of silver(I), the N-Ag-N angle being 164.2(1) degrees, and only weak silver-nitrate interactions. In addition there is an interaction giving pairs of parallel chains as the main structural theme. The 2,5-dimethylpyrazine compound has approximately trigonal-planar coordination, also binding one nitrate at the relatively short Ag-O distances 2.444(3) angstroms and 2.484(3) angstroms, respectively, for the two crystallographically different silver atoms. This also results in a 1D coordination polymer that, despite the large differences in the Ag(I) coordination environment, is isostructural with 1. [Ag4(3-aminopyridine)4(NO3)4]n 3 forms a 2D coordination polymer by bridging nitrate ions. The antimicrobial activity of 1-3, and also of [Ag3(2-aminopyridine)4](NO3)3, 4 was screened for 13 different pathogens and substantial activity was shown for 1 against Escherichia coli and Pseudomonas aeruginosa (MIC 4 microg cm(-3)) and somewhat lower activity was registered against Sarcina lutea and Salmonella typhi for 1, Bordetella bronchiseptica for 2, Salmonella typhi and Pseudomonas aeruginosa for 3, and Escherichia coli and Shigella sonnie for 3 (MIC 8 microg cm(-3)). Only low activity was shown against the yeast Candida albicans for 1, 2 and 4 whereas no activity against this pathogen was registered for 3.

Aminopyridines↗
PubMed1985

Nitrate storage and retrieval in Beta vulgaris: Effects of nitrate and chloride on proton gradients in tonoplast vesicles.

The fluorescent probes acridine orange and oxonol-V were used as indicators of pH gradients (DeltapH) and membrane potential differences (DeltaPsi), respectively, in membrane vesicles believed to be derived from the tonoplast of Beta vulgaris L. Low concentrations of nitrate (1-5 mM) caused a partial dissipation of both DeltapH and DeltaPsi at vesicle transport sites distinct from the H(+)-ATPase. In contrast, chloride dissipated only DeltaPsi. A model is proposed in which nitrate and chloride enter the plant cell vacuole in response to a potential generated by the tonoplast H(+)-ATPase. Nitrate but not chloride may then be retrieved for metabolic use by the operation of a nitrate/proton symport at the tonoplast.

Journal Article↗
PubMed1981

In Vivo Determination of Parameters of Nitrate Utilization in Wheat (Triticum aestivum L.) Seedlings Grown with Low Concentration of Nitrate in the Nutrient Solution.

Six genotypes of winter wheat (Triticum aestivum L.) differing in grain protein concentration were grown on a nutrient solution containing low concentrations of NO(3) (-) (2 millimolar). Total NO(3) (-) uptake varied between genotypes but was not related to grain protein content. An in vivo nitrate reductase assay was used to determine the affinity of the enzyme for NO(3) (-), and large phenotypic variations were observed. In vivo estimations of the concentration and size of the metabolic pool were variable. However, the three genotypes with the higher ratios of metabolic pool size to leaf total NO(3) (-) concentration were the high protein varieties. It is proposed that a high affinity of nitrate reductase for nitrate might be a biochemical marker for the capacity of the plant to continue assimilating NO(3) (-) for a longer period during the last stage of growth.The potential use of such physiological criteria as markers is discussed, in particular with respect to breeding programs for the development of plants with efficient nitrogen utilization.

Journal Article↗
PubMed1989

Tungstate, a molybdate analog inactivating nitrate reductase, deregulates the expression of the nitrate reductase structural gene.

Nitrate reductase (NR, EC 1.6.6.1) from higher plants is a homodimeric enzyme carrying a molybdenum cofactor at the catalytic site. Tungsten can be substituted for molybdenum in the cofactor structure, resulting in an inactive enzyme. When nitratefed Nicotiana tabacum plants were grown on a nutrient solution in which tungstate was substituted for molybdate, NR activity in the leaves decreased to a very low level within 24 hours while NR protein accumulated progressively to a level severalfold higher than the control after 6 days. NR mRNA level in molybdate-grown plants exhibited a considerable day-night fluctuation. However, when plants were treated with tungstate, NR mRNA level remained very high. NR activity and protein increased over a 24-hour period when nitrate was added back to N-starved molybdate-grown plants. NR mRNA level increased markedly during the first 2 hours and then decreased. In the presence of tungstate, however, the induction of NR activity by nitrate was totally abolished while high levels of NR protein and mRNA were both induced, and the high level of NR mRNA was maintained over a 10-hour period. These results suggest that the substitution of tungsten for molybdenum in NR complex leads to an overexpression of the NR structural gene. Possible mechanisms involved in this deregulation are discussed.

Journal Article↗
PubMed1999

Butoconazole nitrate 2% for vulvovaginal candidiasis. New, single-dose vaginal cream formulation vs. seven-day treatment with miconazole nitrate. Gynazole 1 Study Group.

OBJECTIVE: To compare the safety and efficacy of a single vaginal dose of a butoconazole nitrate 2% bioadhesive, sustained-release cream* (butoconazole 1-BSR) with a seven-day schedule of miconazole nitrate vaginal cream 2% (miconazole 7). STUDY DESIGN: The clinical trial was conducted according to a randomized, parallel, investigator-blind, multicenter study design. The patients self-administered the respective creams to the posterior vaginal fornix. Two hundred twenty-three patients started the trial and were analyzed for safety. A total of 205 patients qualified for efficacy analysis, 101 receiving butoconazole 1-BSR and 104 using miconazole 7. Patients receiving butoconazole 1-BSR inserted one applicator full of medication once. Those assigned to receive miconazole 7 inserted one applicator full daily for seven days. Patients were evaluated 7-10 and 30 days after completion of therapy. RESULTS: Butoconazole 1-BSR rapidly relieved the signs and symptoms of vulvovaginal candidiasis. The proportion of patients with severe symptoms declined from the pretreatment 20% to 6% on the 1st day, to 3% on the 4th day, and to 2-1% on the 5th-7th day after single-dose application. Eight to ten days after treatment completion, clinical symptoms regressed in 92%, and fungal cultures were negative in 87% of patients. At the 30-day posttreatment visit, 88% of patients remained clinically cured, and 74% had negative fungal cultures. In the miconazole 7 group, the proportion of patients with severe symptoms declined from 23% to 19% after the first dose; thereafter, symptom relief proceeded more rapidly. Eight to ten days after treatment completion, clinical symptoms regressed in 92% and fungal cultures were negative in 87% of patients. At the 30-day follow-up examination, 86% patients were clinically cured, and 77% were culture negative. After single-dose butoconazole 1-BSR, severe symptoms receded faster than after the first dose of miconazole 7, and the difference was statistically significant (P = .01). In all other efficacy parameters, the differences between the two groups were not statistically significant. Neither treatment regimen caused significant adverse events. CONCLUSIONS: This clinical trial demonstrated that butoconazole 1-BSR is an effective and safe alternative to longer-term therapy with miconazole nitrate (seven days) for vulvovaginal candidiasis.

Administration, Topical↗
PubMed2003

[The impact of nitrates and mono-therapy and nitrates combined with angiotensin converting enzyme inhibitors on left ventricular remodeling and exercise capacity in patients after acute myocardial infarction].

The objective of this paper was to evaluate potential beneficial effects of combined treatment with slow-release nitrates and angiotensin converting enzyme inhibitors (ACE) on left ventricular remodeling and exercise capacity in patients after acute myocardial infarction. In this study, 141 patients (aged 34 to 74, mean 56.6 years) with sufficient circulation received combined treatment with 24 hour nitroglycerin infusion followed by oral nitrates (isosorbide mononitrate 50 mg OD) from day 2 day 42 after myocardial infarction and ACE inhibitor (captopril 25 mg BID or enalapril 5 mg BID versus placebo) from day 10 to day 42. On days 10 and 42, echocardiographic examination was carried out and recorded on an optical disc. Simultaneously, on the same days, the treadmill exercise test (modified Bruce protocol) was performed. In the echocardiographic study the left ventricular endodiastolic and endosystolic volumes (biplane Simpson formula), ejection fraction, left ventricular wall motion score and left ventricular mass index were analyzed. Treadmill test criteria, used in the study, included exercise duration time and workload (METS). For each patient the data obtained examination II and I were measured and the differences in their values were classified. The obtained results were analyzed with one-way and three-way ANOVA test. A Kruskal-Wallis test was also used in one variable analysis. Results were analyzed after repartition of patients into groups according type of treatment (angiotensin converting ing enzyme inhibitor or placebo), infarct location (anterior or inferior wall) and enzyme level (CPK < 2000 IU/L or CPK > 2000 IU/L). A p value < 0.1 was considered statistically significant. In a single factor analysis ANOVA proved that the patients treated with nitrates and captopril showed greater improvement in exercise capacity (in METS) than patients treated with enalapril or placebo (+1.26 captopril, +0.2 enalapril and +0.29 placebo, p = 0.043). In addition, a decrease in left ventricular mass index was evident only in patients treated with angiotensin converting enzyme inhibitor (placebo +7.37 gm/m2, captopril -12.17 gm/m2, enalapril -10.14 gm/m2, p = 0.0032). The triple factor analysis ANOVA test revealed that the change in endodiastolic left ventricular volume depends on combination of three factors: infarct location, type of treatment and level of cardiac enzymes (p = 0.009). A decrease in left ventricular endodiastolic volume between day 42 and 10 was observed only in patients with inferior wall infarct and CPK level < 2000 IU/L, irrespective of treatment type and in patients with inferior wall infarct and CPK level > 2000 IU/L treated with angiotensin enzyme inhibitor. We noticed also that heart failure, considered as contraindication to randomization, was in addition the most frequent (up to day 10) cause for study termination and initiation of treatment with angiotensin enzyme inhibitor.

Adult↗
PubMed1986

[Comparative hemodynamics action of glycero-2-nitrate and glycerol trinitrate in various species and the pharmacokinetics of glycerol-2-nitrate in the dog].

Comparative Hemodynamic Activity of Glyceryl 2-Nitrate and Glyceryl Trinitrate in Various Species and Pharmacokinetics of Glyceryl 2-Nitrate in Dog A single dose of glyceryl 2-nitrate (G-2-N) had practically identical hypotensive and cardiovascular activity when administered intravenously or enterally to the anaesthetized rabbit, cat or dog. In all three species the hypotensive and also cardiovascular activity of G-2-N lasted much longer than that of glyceryl trinitrate (GTN, Nitro Mack). In the rabbit, cat and dog enterally active doses of GTN were 500-1000 times greater than parenterally active doses. In all species enterally administered GTN was about 8 times more active than enterally administered G-2-N. G-2-N is 100% bioavailable in the conscious dog.

Animals↗
PubMed1990

Nitrate reductases of Escherichia coli: sequence of the second nitrate reductase and comparison with that encoded by the narGHJI operon.

The structural genes for NRZ, the second nitrate reductase of Escherichia coli, have been sequenced. They are organized in a transcription unit, narZYWV, encoding four subunits, NarZ, NarY, NarW and NarV. The transcription unit is homologous (73% identity) to the narGHJI operon which encodes the genes for NRA, the better characterized nitrate reductase of this organism. The level of homology between the corresponding polypeptides ranges from 69% for the NarW/NarJ pair to 86% for the NarV/NarI pair. The NarZ polypeptide contains the five conserved regions present in all other known molybdoproteins of E. coli and their relative order is the same. The NarY polypeptide, which contains the same four cysteine clusters in the same order as NarH, is probably an electron transfer unit of the complex. Upstream of narZ, an open reading frame, ORFA, is present which could encode a product which has homology (73% identity) with the COOH-terminal end of NarK. The ORFA-narZ intergenic region, however, is about 80 nucleotides long and does not contain the cis-acting elements, NarL and Fnr boxes, nor the terC4 terminator sequence present in the 500 nucleotide narK-narG intergenic region. This might explain why the narZYWV and the narGHJI operons are regulated differently. Our results tend to support the hypothesis that a DNA fragment larger than that encompassing the narGHJI genes has been duplicated.

Amino Acid Sequence↗
PubMed2000

Improvement of capillary zone electrophoresis sensitivity with artificial seawater as the background electrolyte utilizing transient isotachophoresis for the determination of nitrate and nitrate ions in seawater.

We describe capillary zone electrophoresis (CZE) with transient isotachophoresis (ITP) for the determination of low concentrations of nitrite and nitrate ions in seawater. Bromide-free artificial seawater was adopted as background electrolyte (BGE) to eliminate the interference of high concentrations of salts in seawater. To reverse the electroosmotic flow (EOF), 3 mM cetyltrimethylammonium chloride (CTAC) was added to the BGE. High concentrations of chlorate were added to sample solutions as the terminating ion to generate the ITP process before the CZE separation. In general, the stacking effect increased with increasing amounts of chlorate injected into the capillary. The limits of detection (LODs) for nitrite and nitrate were 0.063 and 0.033 mg/L when the chlorate concentration was 600 and 200 mM, respectively; these were half of those obtained by CZE without the transient ITP. The LODs were obtained at a signal to noise ratio (S/N) of 3. The relative standard deviations (RSD, n = 10) of the peak areas for these ions were 3.2 and 2.9%. The RSDs of peak heights for these ions were 1.6 and 2.1%. The RSDs of migration times for these ions were 0.67 and 0.46%.

Electrolytes↗
PubMed1979

[Analytical methods for nitrate and nitrite determination in foods. 3. Spectrophotometric determination of nitrate and nitrite using sulphanilic acid/1-naphylamine, and of nitrite using resorcinol/zirconium (IV) oxychloride].

The Nitrate content of foods may be determined by means of azo-dye coupling after reduction of the nitrate with the aid of active cadmium produced in the sample solution. An easy method for determining nitrite consists in the colorimetric estimation of a coloured chelate formed from nitrite, resorcinol and zirconium(IV) oxychloride.

1-Naphthylamine↗
PubMed2003

Oxygen isotopes in nitrate: new reference materials for 18O:17O:16O measurements and observations on nitrate-water equilibration.

Despite a rapidly growing literature on analytical methods and field applications of O isotope-ratio measurements of NO(3)(-) in environmental studies, there is evidence that the reported data may not be comparable because reference materials with widely varying delta(18)O values have not been readily available. To address this problem, we prepared large quantities of two nitrate salts with contrasting O isotopic compositions for distribution as reference materials for O isotope-ratio measurements: USGS34 (KNO(3)) with low delta(18)O and USGS35 (NaNO(3)) with high delta(18)O and 'mass-independent' delta(17)O. The procedure used to produce USGS34 involved equilibration of HNO(3) with (18)O-depleted meteoric water. Nitric acid equilibration is proposed as a simple method for producing laboratory NO(3)(-) reference materials with a range of delta(18)O values and normal (mass-dependent) (18)O:(17)O:(16)O variation. Preliminary data indicate that the equilibrium O isotope-fractionation factor (alpha) between [NO(3)(-)] and H(2)O decreases with increasing temperature from 1.0215 at 22 degrees C to 1.0131 at 100 degrees C. USGS35 was purified from the nitrate ore deposits of the Atacama Desert in Chile and has a high (17)O:(18)O ratio owing to its atmospheric origin. These new reference materials, combined with previously distributed NO(3) (-) isotopic reference materials IAEA-N3 (=IAEA-NO-3) and USGS32, can be used to calibrate local laboratory reference materials for determining offset values, scale factors, and mass-independent effects on N and O isotope-ratio measurements in a wide variety of environmental NO(3)(-) samples. Preliminary analyses yield the following results (normalized with respect to VSMOW and SLAP, with reproducibilities of +/-0.2-0.3 per thousand, 1sigma): IAEA-N3 has delta(18)O = +25.6 per thousand and delta(17)O = +13.2 per thousand; USGS32 has delta(18)O = +25.7 per thousand; USGS34 has delta(18)O = -27.9 per thousand and delta(17)O = -14.8 per thousand; and USGS35 has delta(18)O = +57.5 per thousand and delta(17)O = +51.5 per thousand.

Mass Spectrometry↗