Betaine in human nutrition

Altered methionine metabolism, DNA methylation and oncogene expression in carcinogenesis. A review and synthesis.

A method is described for the continuous recording of acid gastric secretion in the rat. The stomach of the rat anaesthetized with urethane is perfused with a dilute sodium hydroxide solution by way of the oesophagus and the pH of the fluid emerging from a cannula in the pylorus is registered graphically. In passing through the stomach, the perfusate collects sufficient buffer to act as an approximately linear buffer system over the relevant range, so that the change in pH becomes a measure of acid secretion. The preparation is suitable for the bioassay of secretory stimulants. Ten or more drug doses can be administered in succession in one preparation, so that each animal serves as a self-contained assay unit. Intravenous doses of histamine, methacholine, carbachol and acetylcholine produce a graded and reversible stimulation of acid secretion. The secretory effect of histamine is markedly and specifically potentiated by antihistaminases.

https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1476-5381.1958.tb00190.x

Continuous recording of acid gastric secretion in the rat.

This report describes the synthesis of L- and D-[methyl-11C]methionine in pure enantiomeric forms The compounds were prepared routinely approximately 1,000 times with less than 20 failures Starting with carbon-11 (11C) methyl iodide, a simple one-carbon precursor produced from a one-pot or a two-pot apparatus, L- and D-[methyl-11C]methionine were prepared, respectively, with an optical purity higher than 99% in 40%-90% radiochemical yields The total time for synthesis, starting from [11C]carbon dioxide, was 12-15 min The crude product usually had a radiochemical purity greater than 95% The total time for synthesis, including LC purification, was 20-30 min The radiochemical purity of the product in each case was greater than 98%

http://jnm.snmjournals.org/content/28/6/1037.full.pdf

Synthesis of L- and D-[methyl-11C]methionine.

In recent years, there has been an upsurge of interest in elevation of the plasma concentration of homocysteine and closely related metabolites as an independent risk factor for cardiovascular disease (reviewed, for example, in References 1 through 3). Homocysteine itself is a thiol(sulfhydryl-) containing amino acid, but in normal human plasma and other tissues, a variety of related disulfide derivatives may be present. Different authors have written about these compounds and their effects by using differing terminologies. To promote clarity of meaning and to minimize uncertainty, perhaps even confusion, it is important that each article discussing these compounds either defines explicitly the terms and/or abbreviations used or cites a prior publication in which such definitions are provided. Optimally, a more uniform consensus terminology will be developed and adopted by the field. This article describes very briefly the structures of the relevant compounds and sets forth terms and abbreviations that, it is hoped, may provide a basis

Homocysteine and Its Disulfide Derivatives: A Suggested Consensus Terminology

Evidence of the physiological specificity of methionine in regard to the methylthiol group: the synthesis of s-ethylhomocysteine (ethionine) and a study of its availability for growth

Helen M. Dyer

Papers

Evidence of the physiological specificity of methionine in regard to the methylthiol group: the synthesis of s-ethylhomocysteine (ethionine) and a study of its availability for growth

The growth-promoting properties of homocystine when added to a cystine-deficient diet and the proof of structure of homocystine

A relationship between the nature of the vitamin b complex supplement and the ability of homocystine to replace methionine in the diet

Purification of the Pressor Principle of the Posterior Lobe of the Pituitary Gland by Electrophoresis

Electrophoresis of posterior pituitary gland preparations