[Clinical significance of serum CEA determination in the diagnosis of colo-rectal cancer]

Serum CEA levels of 581 specimens obtained from 350 colo-rectal cancer patients and 61 specimens from 54 non-tumor subjects were determined by sandwich method of CEA-EIA McAb kit supplied by the Beijing Institute of Biological Products. In patients with primary colo-rectal cancer, the serum CEA level was 15.0 +/- 52.1 ng/ml and 37.9% of patients gave a CEA level greater than 5 ng/ml. In recurrent colo-rectal cancer patients, serum CEA increased to 124.2 +/- 454.8 ng/ml with a positive rate of 78.0%. Both the CEA value and the positive rate of patients in clinically tumor-free period after surgery were 2.9 +/- 2.2 ng/ml and 16.5%, respectively. Serial follow-up CEA assays in selected cases were helpful to reflect the clinical status. Generally, CEA is useful to predict prognosis and to guide follow-up management.

Isolation and characterization of rabbit gastrin

The heptadecapeptide form the rabbit gastrin was extracted from 16 rabbit antra and purified by a combination of DEAE Sephadex, C-18 SEP PAK cartridges, fast performance liquid chromatography (FPLC) and reverse phase high pressure liquid chromatography (HPLC) steps. After the HPLC purification, a sharp, single peak of gastrin-like immunoreactivity was detected that had the same absorption to immunoreactivity ratio as human gastrin. An amino terminal pyrrolidone carboxylic acid blocking group was removed by incubation with pyrrolidone carboxylic peptidase. The amino acid analysis, microsequence analysis and mass spectrometry all confirmed the structure of rabbit gastrin being pQGPWLQEEEEAYGWMDFamide. This sequence is identical to human gastrin-17 except for glutamine in position 6 which replaces glutamate in human gastrin. Both sulfated and unsulfated rabbit gastrin-17 were characterized by mass spectrometry.