Long-Term Source Apportionment of Ammonium in PM at a Suburban and a Rural Site Using Stable Nitrogen Isotopes.

Ammonia gas (NH) is an important alkaline air pollutant and a precursor to particulate matter, and its source has been thought to be agricultural, but in recent years, nonagricultural sources have been suspected. In this study, stable nitrogen isotope ratios of ammonium (δN-NH) in fine particulate matter (PM) were measured at a suburban site and a rural site in Japan. Then, the long-term sources of NH were identified using the δN-NH and an isotopic mixing model.

Ion-exchange resin and denitrification pretreatment for determining δ N-NH , δ N-NO , and δ O-NO values.

Rationale: There has never been a highly sensitive method for simultaneously measuring the δ N and δ O values of nitrate ions (NO ) and the δ N values of ammonium ions (NH ) in particulate matter using denitrifying bacteria. In this study, we explored a method that combines use of an anion-exchange resin and denitrifying bacteria to make such measurements.

Methods: The δ N-NH values of samples obtained using the hypobromite and denitrifying bacteria method were measured by isotope ratio mass spectrometry.

Heart-cutting two-dimensional liquid chromatography combined with isotope ratio mass spectrometry for the determination of stable carbon isotope ratios of gluconic acid in honey.

Liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is used to analyze various types of samples, including foodstuffs, to determine their authenticity and trace their origin on the basis of their stable carbon isotope ratios (δC). However, multicomponent samples are difficult to analyze. For example, determining the δC values of the organic acids in honey is complicated by the presence of large amounts of carbohydrates.

Stable carbon isotope ratios for organic acids in commercial honey samples.

Stable carbon isotope ratios (δC) for glucose, fructose, disaccharides, trisaccharides, and organic acids in 116 commercial honey samples were measured by LC/IRMS. On the basis of EA/IRMS and LC/IRMS authenticity criteria, 39 of the samples were judged to have been adulterated. The δC values for organic acids from pure honey, reported here for the first time, ranged from -33.

Online wet oxidation/isotope ratio mass spectrometry method for determination of stable carbon isotope ratios of water-soluble organic carbon in particulate matter.

Rationale: Water-soluble organic carbon (WSOC) is formed by oxidation of organic compounds in particulate matter (PM) and accounts for 25-80% of the organic carbon in PM. Stable carbon isotope ratio (δ C) analysis is widely used to identify the sources of PM, but determining the δ C values of WSOC is complicated and requires a time-consuming pretreatment process.

Methods: We have developed an online wet oxidation/isotope ratio mass spectrometry method with a reduced pretreatment time.

Determination of carbon isotope ratios for honey samples by means of a liquid chromatography/isotope ratio mass spectrometry system coupled with a post-column pump.

Rationale: Liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) has been used to authenticate and trace products such as honey, wine, and lemon juice, and compounds such as caffeine and pesticides. However, LC/IRMS has several disadvantages, including the high cost of the CO membrane and blocking by solidified sodium persulfate. Here, we developed an improved system for determining carbon isotope ratios using LC/IRMS.

Classification of nine malathion emulsion samples by using carbon isotope ratios and the ratio of organic solvents.

The compound specific isotope analysis is nowadays an important and powerful tool in geochemical, environmental and forensics field. On November 2013, Aqli Foods Corporation in Japan dealt with complaints about stench from frozen foods produced. Subsequently, very high concentrations of organophosphorus pesticide as malathion, ethylbenzene and xylene were detected in recovered frozen foods.

Morphological and Functional Attenuation of Degeneration of Peripheral Neurons by Mesenchymal Stem Cell-Conditioned Medium in Spinocerebellar Ataxia Type 1-Knock-in Mice.

Aims: Spinocerebellar ataxia type 1 (SCA1) is caused by the ataxin-1 protein (ATXN1) with an abnormally expanded polyglutamine tract and is characterized by progressive neurodegeneration. We previously showed that intrathecal injection of mesenchymal stem cells (MSCs) during the nonsymptomatic stage mitigates the degeneration of the peripheral nervous system (PNS) neurons in SCA1-knock-in (SCA1-KI) mice. We tested in this study whether the therapeutic effects of MSCs in SCA1-KI mice could be reproduced with MSC-releasing factor(s).

Mesenchymal stem cells attenuate peripheral neuronal degeneration in spinocerebellar ataxia type 1 knockin mice.

Spinocerebellar ataxia type 1 (SCA1) is a devastating neurodegenerative disorder in which an abnormally expanded polyglutamine tract is inserted into causative ataxin-1 proteins. We have previously shown that SCA1 knockin (SCA1-KI) mice over 6 months of age exhibit a degeneration of motor neuron axons and their encasing myelin sheaths, as reported in SCA1 patients. We examined whether axon degeneration precedes myelin degeneration or vice versa in SCA1-KI mice and then attempted to mitigate motor neuron degeneration by intrathecally administering mesenchymal stem cells (MSCs).

Mesenchymal stem cells as a potential therapeutic tool for spinocerebellar ataxia.

Spinocerebellar ataxia (SCA) is a devastating progressive neurodegenerative disorder, for which no effective treatments have been developed. However, some studies have shown that an intracerebellar or intrathecal injection of mesenchymal stem cells (MSCs) was partially effective in some genetic mouse models of cerebellar ataxia such as SCA1 and Lurcher mutant. MSCs likely exert their therapeutic efficacy by secreting innate factors to induce neuronal growth and synaptic connection and reduce apoptosis.

Cranial irradiation induces bone marrow-derived microglia in adult mouse brain tissue.

Postnatal hematopoietic progenitor cells do not contribute to microglial homeostasis in adult mice under normal conditions. However, previous studies using whole-body irradiation and bone marrow (BM) transplantation models have shown that adult BM cells migrate into the brain tissue and differentiate into microglia (BM-derived microglia; BMDM). Here, we investigated whether cranial irradiation alone was sufficient to induce the generation of BMDM in the adult mouse brain.

Impairment of spinal motor neurons in spinocerebellar ataxia type 1-knock-in mice.

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by the expansion of polyglutamine repeats in the Ataxin-1 protein. An accumulating body of cerebellar, histological and behavioral analyses has proven that SCA1-knock-in mice (in which the endogenous Atxn1 gene is replaced with mutant Atxn1 that has abnormally expanded 154 CAG repeats) work as a good tool, which resembles the central nervous system pathology of SCA1 patients. However, the peripheral nervous system pathology of the model mice has not been studied despite the fact that the clinical manifestation is also characterized by peripheral involvement.