Distinguishing glutamate and glutamine in in vivo 1 H MRS based on nuclear spin singlet order filtering

PURPOSE

The signals of glutamate (Glu) and glutamine (Gln) are often significantly overlapped in routine ¹ H-MR spectra of human brain in vivo. Selectively probing the signals of Glu and Gln in vivo is very important for the study of the metabolisms in which Glu and Gln are involved.

METHODS

The Glu-/Gln- targeted pulse sequences are developed to selectively probe the signals of Glu and Gln. The core part of the Glu-/Gln- targeted pulse sequences lies on the preparation of the nuclear spin singlet orders (SSOs) of the five-spin systems of Glu and Gln. The optimal control method is used to prepare the SSOs of Glu and Gln with high efficiency.

RESULTS

The Glu-/Gln- targeted pulse sequences have been applied on phantoms to selectively probe the signals of Glu and Gln. Moreover, in the in vivo experiments, the signals of Glu and Gln in human brains of healthy subjects have been successfully probed separately.

CONCLUSION

The developed Glu-/Gln- targeted pulse sequences can be used to distinguish the ¹ H-MR signals of Glu and Gln in human brains in vivo. The optimal control method provides an effective way to prepare the SSO of a specific spin system with high efficiency and in turn selectively probe the signals of a targeted molecule.

Multiple-targeting NMR signal selection by optimal control of nuclear spin singlet

Selectively probing specific molecules in complex mixtures with nuclear magnetic resonance promises new insights into molecular structures or molecular interaction. Such a study often can be further facilitated when two or more objects in chemical moieties of interest can be precisely targeted. Herein, we proposed a novel method to implement the multiple-targeting signal selection by optimal control of the spin singlets of two or more targeted spin systems from one or more molecules. This method can endow the conventional nuclear magnetic resonance (NMR), magnetic resonance image (MRI) and magnetic resonance spectrum (MRS) with the multiple-targeting signal selectivity to selectively probe several targeted molecules and/or chemical groups simultaneously.

Rapid Identification of Adulteration in Edible Vegetable Oils Based on Low-Field Nuclear Magnetic Resonance Relaxation Fingerprints

Most current approaches applied for the essential identification of adulteration in edible vegetable oils are of limited practical benefit because they require long analysis times, professional training, and costly instrumentation. The present work addresses this issue by developing a novel simple, accurate, and rapid identification approach based on the magnetic resonance relaxation fingerprints obtained from low-field nuclear magnetic resonance spectroscopy measurements of edible vegetable oils. The relaxation fingerprints obtained for six types of edible vegetable oil, including flaxseed oil, olive oil, soybean oil, corn oil, peanut oil, and sunflower oil, are demonstrated to have sufficiently unique characteristics to enable the identification of the individual types of oil in a sample. By using principal component analysis, three characteristic regions in the fingerprints were screened out to create a novel three-dimensional characteristic coordination system for oil discrimination and adulteration identification. Univariate analysis and partial least squares regression were used to successfully quantify the oil adulteration in adulterated binary oil samples, indicating the great potential of the present approach on both identification and quantification of edible oil adulteration.

Shrew submaxillary gland epidermal growth factor: homologous radioreceptor assay and mitogenic activity

A homologous radioreceptor assay was developed to determine the epidermal growth factor (EGF) contents of the shrew submaxillary glands. The results supported previous findings by heterologous radioreceptor assay that this gland in the shrew contained a high level of EGF. This EGF was also found to be a powerful mitogen in two fibroblast cell lines.

Studies on shrew (Suncus murinus) epidermal growth factor

The shrew SMG contains a very high level of EGF. By heterologous radioreceptor assay, the EGF content was determined to be about 300 pmol/mg wet weight in the male. The content is sex dependent; in the female gland, it is only 4% of the male gland level. EGF level and EGF receptor content in other tissues showed a reciprocal distribution pattern with the parotid gland containing the second highest level of EGF and the liver containing the largest amount of EGF receptor. Shrew EGF is heat stable. It could induce early eyelid opening and incisor eruption in neonatal rat pups at a very low dose level. There is apparently no high molecular weight form of EGF in shrew tissues and body fluids. However, gel chromatography revealed that the foetus contained multiple forms of EGF. The contribution of a high EGF level to the active life in adult shrews and the exceptionally high growth rate in shrew pups are discussed.