Continuous records of gastric ρh in situ and their possible use in pre-operative assessment of peptic ulcer patients

Grieve, John

doi:10.1002/bjs.18004921415

Cited by 9 publications

(6 citation statements)

References 28 publications

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“…Ingestion of certain foods may cause the pH to increase to pH 7, but returns to its normal level within 15 to 20 min (Grieve, 1961). Based on our in vitro studies with the guinea pig (Table 1), the human stomach would be an excellent environment for nitrosocarbamate formation should the carbamate and nitrite occur therein at the same time.…”

Section: Resultsmentioning

confidence: 96%

“…Although the pH of the human stomach varies according to eating habits, the normal resting stomach ranges from pH 1 to 2 (Goldstein et al, 1974;Grieve, 1961). Following a meal, the pH may increase to about pH 7, but returns to pH 1-2 within about 20 min (Grieve, 1961;Noller and Khodabakhah, 1964).…”

Section: Discussionmentioning

confidence: 96%

“…Following a meal, the pH may increase to about pH 7, but returns to pH 1-2 within about 20 min (Grieve, 1961;Noller and Khodabakhah, 1964). It is quite likely, therefore, that in humans carbamates and nitrite would occur simultaneously in an environment ideal for nitrosation; in our study with rats, the stomach acidity was never observed to fall below pH 3.0.…”

Section: Discussionmentioning

confidence: 97%

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In vivoformation of nitrosocarbamates in the stomach of rats and guinea pigs

Rickard

Dorough

1984

Journal of Toxicology and Environmental Health

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The N-nitrosocarbamates are potent mutagens and carcinogens, and have been synthesized under acid conditions that prevail in the human stomach. However, it has never been documented that nitrosocarbamates are actually formed in vivo in the stomach of any mammalian species. Using 14C-labeled carbaryl and carbofuran, attempts were made to isolate the nitroso derivatives from the stomach contents of rats and guinea pigs treated orally with the carbamate and sodium nitrite. Only trace quantities of nitrocarbamate were recovered from the rat stomach, whereas 0.5 to 2.0% of the carbamate doses were isolated as the nitroso derivative from the contents of the guinea pig stomach. The rather low apparent yields resulted in part from the instability of the nitrosocarbamates and from absorption of the carbamate and/or nitrosocarbamate from the stomach. Higher rates of synthesis were indicated by incubating the carbamates with sodium nitrite in the presence of the stomach contents at 37 degrees C for 15 min. About 30% nitrosation occurred with the guinea pig and about 0.5% with the rat. The difference was attributed to the pH of the gastric contents. For the rat, the pH ranged from 3 to 5; gastric contents of the guinea pig had a pH between 1 and 2. Since the pH of the human stomach is also in the pH 1-2 range, it is likely that nitrosation of carbamates in humans would be very similar to that in the guinea pig.

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Section: Resultsmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

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In vivoformation of nitrosocarbamates in the stomach of rats and guinea pigs

Rickard

Dorough

1984

Journal of Toxicology and Environmental Health

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“…As the pK, values of the amine used in the present studies are reported to be -2.0, the optimum nitrosation takes place at pH 1-2 (Jencks and Regenstein 1968;De Jong et a1 1985). Since the pH of the normal and resting human stomach is also in the pH range 1-2, it is likely that there would be enhanced endogenous nitrosation within this pH range (Grieve 1961;Goldstein et a1 1974). The present study indicates that the human stomach can be an excellent environment for nitrosamine formation as the amines and nitrite occur therein simultaneously.…”

Section: Discussionmentioning

confidence: 99%

Nitrosation of some food‐related tetrahydro‐β‐carboline‐3‐carboxylic acids

Salvi

Choughuley

1990

J Sci Food Agric

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A number of p-carbolines whose nitroso derivatives are known mutagens and carcinogens are formed in cooked and processed foods. I n this work the formation of N-nitroso derivatives porn 1 -substituted-I,2,3,4-tetrahydro- 9H-p yrido[3,4-b] indole-3-carboxylic acid ( I -R-TH BC-3-COO H ) and nitrite in aqueous solution was studied. The effect of reaction p H , nitrite concentration and duration of the reaction was evaluated. The yield of Nnitroso-1-R-THBC-3-COOH ut 37°C was enhanced ut low pH (about pH 2)and reached a maximum within 1 h when the stoichiometric amount was used in the reaction, Formation of the nitroso derivative was detected even when only half the stoichiometric quantity was used.

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“…In an investigation of the pH of a solution, the glass electrode as well as the reference electrode are generally placed in the solution whose pH is to be measured. In the intragastric determination of pH on patients several investigators have placed the reference electrode on the rectal mucosa, oral mucosa (2,16,17,30), or on the skin (8,15,21,24,25,26) instead of having both electrodes in the stomach (6,7,9,23,24). Below, the technique and accuracy of the skin electrode method will be described.…”

mentioning

confidence: 99%

Continuous Intragastric pH Determination

Kristensen¹

1965

Journal of Internal Medicine

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Continuous records of gastric ρh in situ and their possible use in pre-operative assessment of peptic ulcer patients

Cited by 9 publications

References 28 publications

In vivoformation of nitrosocarbamates in the stomach of rats and guinea pigs

In vivoformation of nitrosocarbamates in the stomach of rats and guinea pigs

Nitrosation of some food‐related tetrahydro‐β‐carboline‐3‐carboxylic acids

Continuous Intragastric pH Determination

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