Glycerine Determination in Tissues

Christensen, Halvor N.; Riggs, Thomas R.; Ray, Nancy E.

doi:10.1021/ac60058a057

Cited by 42 publications

(16 citation statements)

References 15 publications

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“…Peptides were estimated by determination of the glycine content before and after acid hydrolysis, as described by Newey & Smyth (1959). Glycine was determined by the method of Alexander, Landwehr & Seligmann (1945) as modified by Christensen, Riggs & Ray (1951). Glycine, glycylglycine, L-methionine and a methioiiine hydroxy analogue (DL-oc-OH-y-methylmercaptobutyric acid) were obtained commercially.…”

Section: H Ne We Y and D H Smythmentioning

confidence: 99%

Cellular mechanisms in intestinal transfer of amino acids

Newey¹,

Smyth²

1962

The Journal of Physiology

120

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Newey & Smyth (1960a) have shown that dipeptides present in the lumen of the intestine can enter the mucosal cells and undergo intracellular hydrolysis. The present work was undertaken to investigate these processes further. One problem was to determine whether entry of peptide could be accounted for by diffusion, or whether other processes were involved. If entry involves other processes, the question is raised as to the nature of these, and in particular their relationship to the mechanism for entry of amino acids. Having entered the cells the peptide is hydrolysed, and a further question arises about the mechanism of transfer of the amino acids liberated.While entry and hydrolysis of peptide can be shown to take place experimentally, it is not known how far these represent physiological processes. Quite apart, however, from the question whether peptide absorption plays a significant role in absorption of protein, the use of peptides has value from another point of view, in that it provides a means of getting amino acids inside the epithelial cells without these amino acids having entered as such. This offers a possibility of studying cellular mechanisms for amino-acid transfer, and of trying to separate different stages in aminoacid transfer by the cells. Preliminary accounts of this work have been given by Newey & Smyth (1960b. METHODSIn viro. The preparation used was the sac of everted small intestine of the rat (Wilson & Wiseman, 1954a) and the procedure was that described by Parsons, Smyth & Taylor (1958), except that in most of the experiments the sacs were not weighed as fluid transfer was not studied. In the experiments where fluid transfer was studied the sacs were weighed and transfers calculated as described by Parsons et al. (1958). The sacs were made from the middle fifth of the combined jejunum and ileum of the rat. They were filled with bicarbonate saline (Krebs & Henseleit, 1932) with or without added glucose, and were shaken in the same solution with a gas phase of 5 % CO2 and 95 % 02. In anaerobic experiments the gas phase was 5 % CO2 and 95 % N2. Amino acids or peptides were present as described subsequently. At the end of the experiment, which, unless otherwise stated, lasted 30 min the amino acid or peptide present in various sites was determined. In describing the results the * J. G. Graves Research Fellow.

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Section: H Ne We Y and D H Smythmentioning

confidence: 99%

Cellular mechanisms in intestinal transfer of amino acids

Newey¹,

Smyth²

1962

The Journal of Physiology

120

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“…Crude extracts were analyzed for hydroxyprollne (20), prollne (21), glycine (22), and tyrosine (23) before dialysis and, in some cases, after dialysis against 0.41 u NaC1. Analyses for the first three amino acids were made on hydrolysates prepared by heating 1 ml.…”

Section: Analyses Of Extractsmentioning

confidence: 99%

Studies on the Formation of Collagen

Gross

1959

The Journal of Experimental Medicine

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The essential role of ascorbic acid in collagen formation has been shown b y numerous histological and biochemical studies (2-7). The mode of action, however, is still in doubt.The question as to whether a deficiency of ascorbic add prevents synthesis of collagen molecules or interferes with subsequent polymerization to fibrils was raised by Wolbach (2), who favored the latter possibility. Biochemical studies of the carrageenan granuloma by van Robertson and Schwartz (7) and of healing skin wounds in scorbutic guinea pigs by Gould and Woessner (6) led these investigators to postulate that ascorbie add was required for the hydroxylation of proline to hydroxyproline in the polypeptlde chain of a precursor of collagen. The hypothetical proline-rich, hydroxyproline-poor precursor, they suggested, is synthesized normally in the scorbutic state but not hydroxylated, and this defect accounts for the relatively large amounts of proline with little hydroxyproline found in scorbutic granulation tissues. As yet, there has not been a reported success in isolating this precursor.Biochemical studies of collagen formation in granulation tissue (open wounds, granulomas, and implanted plastic sponges) are complicated by the variety of physiologic responses involved in healing. A method for the study of collagen formation in the intact scorbutic animal was provided by the discovery of neutral salt-extractible collagen in intact dermis (8,9). This fraction (in tissues which are not undergoing degradation) is newly synthesized and appears to be converted to insoluble fibrils (10-12).Studies of the solubility of extracted collagen in vitro have indicated a possible mechanism for this process (13).

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“…Glucose and other reducing sugars were estimated by the method of Nelson (1944) as modified by Somogyi (1945), or by the glucose oxidase method of Huggett & Nixon (1957) as modified by Dahlqvist (1961). Glycine was estimated after de-proteinization by the method of Alexander, Landwehr & Seligman (1945) as modified by Christensen, Riggs & Ray (1951). Glycyl-glycine was determined by estimating free and bound glycine as described by Newey & Smyth (1959).…”

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confidence: 99%