Biomedical subjects

P L Rayford

Publications and source records attributed to P L Rayford.

At least 163 records · Page 9Linked to original sources

PubMed1975

Identification of cholecystokinin-secreting cells.

Cholecystokinin (C.C.K.)-producing cells were identified in the mucosa of the upper small intestine in man and other mammals by immunocytochemical techniques and electron microscopy on semi-thin and serial thin sections. Ultrastructural studies suggested that the C.C.K.-producing cells resemble I cells of the modified Wiesbaden classification. The combination of these techniques provides a simple and reliable method of identifying C.C.K. cells in human biopsy material and will be useful in the investigation and diagnosis of gut endocrine dysfunctions.

Animals↗

PubMed1975

Cholecystokinin metabolism in man and dogs.

We have developed a sensitive, specific and reproducible radioimmunoassay for cholecystokinin (CCK) with which basal levels of CCK of between 400-800 pg/ml have been measured in normal man, in patients with diabetes and with duodenal ulcer disease, and in normal dogs. After a meal, circulating levels of CCK rose to 1000-1200 pg/ml in human subjects. Release of CCK was more rapid in diabetic and duodenal ulcer patients than in normal subjects, but elevated postprandial levels persisted much longer in normal subjects. Patients with the Zollinger-Ellison syndrome had elevated values of cholecystokinin which rose after a meal. Lack of correlation between elevated basal levels of gastrin and CCK in patients with the Zollinger-Ellison syndrome suggest that the hypercholecystokininemia may be absolute. The disappearance half-time of exogenous CCK was about 21/2 minutes in normal subjects as well as in diabetic and duodenal ulcer patients. Studies in dogs demonstrated no uptake of basal levels of cholecystokinin by the kidney; on infusion of exogenous CCK-33, the kidney extracted 43% of the total CCK presented and 56% of the integrated CCK. We conclude that: 1) circulating basal and postprandial levels of CCK may be measured in a reproducible fashion; 2) postprandial release of CCK is more rapid in diabetic and duodenal ulcer patients than in normal man; 3) the disappearance half-time of exogenous CCK in man and dogs is about 21/2 minutes; 4) the kidney is a major site for uptake of CCK.

Animals↗

PubMed1975

Interlaboratory reproducibility of gastrin measurements by radioimmunoassay.

A collaborative study was conducted to determine interlaboratory variations in the measurement of gastrin by radioimmunoassay (RIA). A kit containing reagents for a communal RIA method, as well as test samples containing different amounts of human synthetic gastrin (SHG I) and test samples of serum from a fasting normal patient admixed with varying volumes of serum from a patient with the Zollinger-Ellison syndrome, was sent to each collaborating investigator. Each investigator was requested to measure the gastrin concentrations in test samples by means of the communal RIA method, as well as the RIA method utilized in his or her laboratory. Use of the communal RIA method resulted in no significant interlaboratory variation in the determination of gastrin concentration in SHG I test samples and a maximum two- to threefold variation in determination of gastrin serum test samples. In contrast, when individual RIA methods were used to measure gastrin concentrations, the amount of SHG I in test samples reported by one laboratory was significantly different than that reported by the other three. In addition, use of different RIA methods resulted in a 2- to 19-fold interlaboratory variation in serum gastrin measurements and the maximum variation was found when the gastrin in normal fasting serum was measured. Increased variations in results, when different RIA methods were used, may be due to differences in preparation and purification of labeled antigen, to differences in separation of bound from free hormone, and to differences in the antibodies themselves.

Gastrins↗

PubMed1975