Procedure for rapid determination of δ15N and δ18O values of nitrate: development and application to an irrigated rice paddy watershed.

The dual isotope approach using the stable isotope ratios of nitrate nitrogen (δ(15)N(NO3)) and oxygen (δ(18)O(NO3)) is a strong tool for identifying the history of nitrate in various environments. Basically, a rapid procedure for determining δ(15)N(NO3) and δ(18)O(NO3) values is required to analyze many more samples quickly and thus save on the operational costs of isotope-ratio mass spectrometry (IRMS). We developed a new rapid procedure to save time by pre-treating consecutive samples of nitrous oxide microbially converted from nitrate before IRMS determination. By controlling two six-port valves of the pre-treatment system separately, IRMS determination of the current sample and backflush during the next sample pre-treatment period could be conducted simultaneously. A set of 89 samples was analyzed precisely during a 25-h continuous run (17 min per sample), giving the fastest reported processing time, and simultaneously reducing liquid nitrogen and carrier helium gas consumption by 35%. Application of the procedure to an irrigated rice paddy watershed suggested that nitrate concentrations in river waters decreased in a downstream direction, mainly because of the mixing of nitrate from different sources, without distinct evidence of denitrification. Our procedure should help with more detailed studies of nitrate formation processes in watersheds.

Natto (fermented soybeans)-induced anaphylaxis in a surfer with the possibility of sensitization to poly(γ-glutamic acid) from cutaneous exposure to jellyfish sting: a case report.

BACKGROUND: We report a case of anaphylaxis induced by natto (fermented soybeans) allergy that occurred following dermal sensitization from a jellyfish sting. CASE PRESENTATION: A 49-year-old male presented to the emergency room complaining of an acute onset of erythema with pruritis that appeared while he was surfing. Given that his heart rate dropped to ~ 40 bpm without a decline in blood pressure or oxygen saturation, we suspected anaphylaxis and administered 0.5 mg of adrenaline intramuscularly. Immediately after the muscular adrenaline injection, his heart rate recovered to ~ 60-70 bpm. CONCLUSIONS: The major allergen that induces natto allergy is poly(γ-glutamic acid) (PGA), which is present in its mucilage. Given that PGA is also produced by jellyfish tentacles, it can be inferred that the PGA sensitization occurred via dermal exposure to jellyfish PGA. This is an example of a food allergy induced by animal stings. As PGA is a high-molecular-weight polymer, natto allergy, despite being IgE-mediated, often presents with late-onset anaphylaxis, which typically develops half a day after digestion. PGA has a wide range of applications in pharmaceuticals, cosmetics, and foods. Patients may develop allergic symptoms and experience repeated anaphylaxis with no known cause. Therefore, it is important to obtain a detailed medical history and individually instruct patients suspected of being allergic to PGA to avoid PGA-containing products.

Central Nervous System Adverse Reactions to Amantadine Intoxication: A Case Report and Analysis of JADER.

BACKGROUND/AIM: A few case reports of central nervous system (CNS) symptoms caused by amantadine intoxication have been published, detailing various types of symptoms and differing times to onset. We encountered a patient who developed CNS symptoms with amantadine. This prompted us to investigate the types, time to onset, and outcome of CNS adverse reactions to amantadine by analyzing data from a pharmacovigilance database. PATIENTS AND METHODS: The patient was evaluated at Chutoen General Hospital, Shizuoka, Japan. Analysis was performed using the Japanese Adverse Drug Event Report (JADER) database. RESULTS: In our case, the amantadine blood concentration was 4,042 ng/ml, i.e., in the toxic range. The time to onset was 26 days for dyskinesia and 90 days for depressed level of consciousness. Symptoms resolved when amantadine was discontinued. The JADER database contained 974 cases of adverse reactions to amantadine. The most frequently reported CNS adverse reaction was hallucination, with a reporting odds ratio of 64.28 (95% confidence interval=52.67-78.46). Positive signals were detected for all CNS adverse reactions. For all CNS reactions, clinical outcomes were poor in a comparatively low percentage of cases. Most CNS reactions occurred soon after administration of amantadine, usually within approximately one month. CONCLUSION: Because most CNS adverse reactions to amantadine usually occur within approximately one month of initiating treatment, healthcare providers should exercise heightened vigilance in monitoring patients for such reactions during this period.

Mechanism for regulation of the putrescine utilization pathway by the transcription factor PuuR in Escherichia coli K-12.

In Escherichia coli, putrescine is metabolized to succinate for use as a carbon and nitrogen source by the putrescine utilization pathway (Puu pathway). One gene in the puu gene cluster encodes a transcription factor, PuuR, which has a helix-turn-helix DNA-binding motif. DNA microarray analysis of an E. coli puuR mutant, in which three amino acid residues in the helix-turn-helix DNA binding motif of PuuR were mutated to alanine to eliminate DNA binding of PuuR, suggested that PuuR is a negative regulator of puu genes. Results of gel shift and DNase I footprint analyses suggested that PuuR binds to the promoter regions of puuA and puuD. The binding of wild-type PuuR to a DNA probe containing PuuR recognition sites was diminished with increasing putrescine concentrations in vitro. These results suggest that PuuR regulates the intracellular putrescine concentration by the transcriptional regulation of genes in the Puu pathway, including puuR itself. The puu gene cluster is found in E. coli and closely related enterobacteria, but this gene cluster is uncommon in other bacterial groups. E. coli and related enterobacteria may have gained the Puu pathway as an adaptation for survival in the mammalian intestine, an environment in which polyamines exist at relatively high concentrations.

A putrescine-inducible pathway comprising PuuE-YneI in which gamma-aminobutyrate is degraded into succinate in Escherichia coli K-12.

Gamma-aminobutyrate (GABA) is metabolized to succinic semialdehyde by GABA aminotransferase (GABA-AT), and the succinic semialdehyde is subsequently oxidized to succinate by succinic semialdehyde dehydrogenase (SSADH). In Escherichia coli, there are duplicate GABA-ATs (GabT and PuuE) and duplicate SSADHs (GabD and YneI). While GabT and GabD have been well studied previously, the characterization and expression analysis of PuuE and YneI are yet to be investigated. By analyzing the amino acid profiles in cells of DeltapuuE and/or DeltagabT mutants, this study demonstrated that PuuE plays an important role in GABA metabolism in E. coli cells. The similarity of the amino acid sequences of PuuE and GabT is 67.4%, and it was biochemically demonstrated that the catalytic center of GabT is conserved as an amino acid residue important for the enzymatic activity in PuuE as Lys-247. However, the regulation of expression of PuuE is significantly different from that of GabT. PuuE is induced by the addition of putrescine to the medium and is repressed by succinate and low aeration conditions; in contrast, GabT is almost constitutive. Similarly, YneI is induced by putrescine, while GabD is not. For E. coli, PuuE is important for utilization of putrescine as a sole nitrogen source and both PuuE and YneI are important for utilization of putrescine as a sole carbon source. The results demonstrate that the PuuE-YneI pathway was a putrescine-inducible GABA degradation pathway for utilizing putrescine as a nutrient source.

Accumulation and mobility of zinc in soil amended with different levels of pig-manure compost.

Applying manure compost not only results in zinc accumulation in the soil but also causes an increase in zinc mobility and enhances zinc leaching. In this study, the physical and chemical characteristics of zinc, zinc profiles, and zinc balance were investigated to characterise the fate of zinc in fields where the quality and amount of pig manure compost applied have been known for 13 years. Moreover, we determined zinc fractionation in both 0.1 mol L(-1)HCl-soluble (mobile) and -insoluble (immobile) fractions. Adsorption of zinc in the soil was enhanced with increasing total carbon content following the application of pig manure compost. The 159.6 mg ha(-1) year(-1)manure applied plot (triplicate) exceeded the Japanese regulatory level after only 6 years of applying pig manure compost, whereas the 53.2 mg ha(-1) year(-1) manure applied plot (standard) reached the regulatory level after 13 years. The zinc loads in the plots were 17.0 and 5.6 kg ha(-1) year(-1), respectively. However, 5.9 % and 17.2 % of the zinc loaded in the standard and the triplicate pig manure compost applied plots, respectively, were estimated to be lost from the plough layer. Based on the vertical distribution of mobile and immobile zinc content, a higher rate of applied manure compost caused an increase in the mobile zinc fraction to a depth of 40 cm. Although the adsorption capacity of zinc was enhanced following the application of pig manure compost, a greater amount of mobile zinc could move downward through the manure amended soil than through non manure-amended soil.

[Risk of Euglycemic Diabetic Ketoacidosis Due to Low-carbohydrate Diet While Taking Empagliflozin: a Case Report].

Empagliflozin reduces blood glucose levels independently of insulin secretion by reducing glucose reabsorption in the proximal renal tubules through inhibition of sodium-glucose cotransporter 2 (SGLT2). Because SGLT2 inhibitors have a different mechanism of action to conventional antidiabetic drugs, recommendations have been issued about the management of specific side effect such as ketoacidosis, urinary tract infection, and genital infection. There have been some reports of SGLT2 inhibitor-associated euglycemic diabetic ketoacidosis (euDKA), but there have been few reports about euDKA in patients with type 2 diabetes using SGLT2 inhibitors while on a low-carbohydrate diet. Here we report a patient who developed euDKA after starting a very low-carbohydrate diet while taking empagliflozin. A 51-year-old man was hospitalized with nausea and vomiting, and investigations revealed metabolic acidosis. euDKA was diagnosed from the information about medications in his drug notebook and a history of eating a low-carbohydrate diet (1900 kcal, consisting of 5.7% carbohydrate, 21.1% protein, 47.3% fat and 25.9% alcohol) for 4 d. The patient improved after infusion of acetated Ringer's solution with 5% glucose and administration of regular insulin. It is necessary for physicians and pharmacists to thoroughly inform patients about the side effects of SGLT2 inhibitors such as ketoacidosis, urinary tract infection, and genital infection. Patients should also be advised about the higher risk of euDKA associated with a low-carbohydrate diet while taking SGLT2 inhibitors.