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C K Ching

Publications and source records attributed to C K Ching.

At least 55 records · Page 3Linked to original sources
PubMed1993

Comparison of two sialosyl-Tn binding monoclonal antibodies (MLS102 and B72.3) in detecting pancreatic cancer.

An immunohistochemical study has been carried out to compare and contrast the cellular distribution of two different sialosyl-Tn antigen binding monoclonal antibodies, MLS102 and B72.3, in the pancreas. MLS102 but not B72.3 monoclonal antibody binding increases with the content of the sialosyl-Tn epitopes. It was found that all 13 pancreatic cancer specimens bound both MLS102 and B72.3 monoclonal antibodies. Their cellular distribution in the cancer was virtually identical. Fifteen of 20 (75%) patients with chronic pancreatitis and five of 10 (50%) normal subjects were B72.3 positive, but MLS102 was completely negative in the latter group. Both monoclonal antibodies bound fetal pancreas diffusely. Thus, when pancreatic ductal cells have undergone malignant transformation, like the fetal pancreas, they express cell surface and secreted glycoconjugates with increased sialosyl-Tn epitopes suggesting enhanced 2-6 sialosyltransferase activity. This study shows that MLS102 is an extremely sensitive and specific tumour marker in the pancreas and that it is better than B72.3 in distinguishing pancreatic cancer from normal and chronic pancreatitis.

Adenocarcinoma↗
PubMed1993

Evaluation of a commercial enzyme-linked immunosorbent assay (ELISA) kit for serological diagnosis of Helicobacter pylori infection in a group of non-ulcer dyspepsia sufferers.

Helicobacter pylori infection of the stomach is associated with gastritis and peptic ulceration and may be causative. A noninvasive test for this organism might be useful in managing some patients with dyspepsia without the need for further investigation. We have evaluated a new commercially available serological test (Helico-G ELISA, Porton Cambridge, UK) for this infection to assess its diagnostic accuracy in a retrospective study of 115 patients with non-ulcer dyspepsia. Sixty-three of these patients (55%) were found to have H. pylori infection and gastritis on histology. A sensitivity of 81% and specificity of 90% were obtained. No significant fall in the antibody titres was found in a subgroup of 15 patients who were selected to complete a course of triple therapy despite significant improvement in their dyspepsia score and confirmed eradication of H. pylori organism in 80% of these patients. We conclude that the test has limited value in aiding clinical decision of managing patients with dyspepsia.

Adult↗
PubMed1992

A new enzyme-linked lectin/mucin antibody sandwich assay (CAM 17.1/WGA) assessed in combination with CA 19-9 and peanut lectin binding assay for the diagnosis of pancreatic cancer.

BACKGROUND: Mucus glycoproteins are often present in the sera of patients with pancreatic cancer, and their detection and quantification can be used in serologic diagnosis. METHODS: A novel enzyme-linked "sandwich" assay (CAM 17.1/WGA) has been developed in which a lectin, wheat germ agglutinin (WGA), is bound to the solid phase to capture serum glycoproteins, and after addition of test sera, a monoclonal antimucin antibody (CAM 17.1) and peroxidase-tagged second antibody are used as a detection system. RESULTS: The test has been applied to sera from 79 patients with pancreatic cancer and 120 controls. The CAM 17.1/WGA assay alone had a sensitivity of 78% and specificity of 76% in the diagnosis of pancreatic cancer. Combination of the CAM 17.1/WGA test with a previously described peanut lectin binding assay (PNA/ELLA) provided a sensitivity of 92% and specificity of 70%, whereas combination of the CAM 17.1/WGA assay with the CA 19-9 radioimmunoassay had a sensitivity of 85% and specificity of 76%. Combination of all three tests had a sensitivity of 94% and specificity of 66%. In nonjaundiced patients, the combination of CAM 17.1/WGA and PNA/ELLA had a sensitivity of 93% and specificity of 79% in the diagnosis of pancreatic cancer. CONCLUSIONS: This new test adds significantly to the armamentarium of serologic tests for pancreatic cancer. These tests are particularly effective when used in combination to detect different mucin-borne carbohydrate antigens. They deserve more widespread use, particularly in examining nonjaundiced patients with unexplained abdominal pain or weight loss.

Adolescent↗
PubMed1990

Purification and characterization of a peanut-agglutinin-binding pancreatic-cancer-related serum mucus glycoprotein.

A high-molecular-weight (approximately 3.5 x 10(3) kDa) peanut agglutinin (PNA)-binding glycoprotein was previously identified as a tumour marker in pancreatic cancer sera. In the present study the density of this glycoprotein has been estimated and further analysis performed using sequential lectin blotting combined with serial mild acid hydrolysis followed by repeated Smith degradation. This has allowed partial in-situ characterization of the carbohydrate side-chains. The PNA-binding glycoprotein variably expresses the blood group H and sialylated Lewis a antigens. H and sialyl Lea expression disappeared after mild acid hydrolysis and T (PNA acceptor) disappeared after the first Smith degradation step. T (beta gal(1-3)alpha galNAc) expression reappeared after a second Smith degradation, suggesting that the backbone regions of the mucin side-chains with this core sequence are built up by the further addition of at least 2 monosaccharides. A model has been constructed showing the minimum variations in side chain structure that would explain the results of the serial degradation and lectin blotting. Purification and caesium chloride density gradient centrifugation show that the intact PNA-binding glycoprotein has a density of greater than 1.48 g/ml, characteristic of a mucin. The development of assays using a panel of monoclonal antibodies (MAbs) or lectins directed against the different carbohydrate epitopes expressed on this mucin may provide better diagnostic accuracy for pancreatic cancer than current marker assays which rely on detection of a single epitope.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1990

Serum diagnostic tests for pancreatic cancer.

Serological tests for pancreatic cancer have been criticized too harshly as a result of being tested in inappropriate roles. They are never likely to become sufficiently specific for screening an asymptomatic population unless some way can be found of defining a population with a particularly high risk for the disease. Nor are they appropriate in the investigation of the jaundiced patient. The markers that are carried by secreted mucins seem the most promising and in view of the marked heterogeneity of carbohydrate expression on mucins a combination of tests for two or three carefully selected markers is likely to be better than one. The high cost per test that results from using commercially available radioimmunoassay kits with a short shelf-life can be reduced by using enzyme-linked assays which have a much longer shelf-life. These tests are likely to be of most help in the investigation of non-jaundiced patients with unexplained abdominal pain or weight loss. In this group of patients it seems probable that serological tests will compliment scanning techniques but further studies are needed to assess this.

Biomarkers, Tumor↗
PubMed1989

Enzyme-linked PNA lectin binding assay compared with CA19-9 and CEA radioimmunoassay as a diagnostic blood test for pancreatic cancer.

Previous studies have shown that sera from patients with pancreatic cancer often contain a mucus glycoprotein that expresses the oncofetal antigen galactose 1-3, N-acetyl galactosamine, which is the T blood group antigen and the binding site for the lectin peanut agglutinin (PNA). An enzyme-linked lectin assay has been developed to quantify PNA-binding glycoproteins in serum and has been evaluated as a serological test for pancreatic cancer. Sera were studied from 53 patients with pancreatic cancer and 154 controls, including benign obstructive jaundice, acute and chronic pancreatitis, chronic liver disease and inflammatory bowel disease. The enzyme-linked peanut lectin assay proved highly reproducible and has 77% sensitivity and 83% specificity for pancreatic cancer, results that are very similar to those achieved in the same sera by CA19-9 radioimmunoassay (75% sensitivity, 82% specificity with the upper limit of normal set at 37 u ml-1). CEA assay proved less useful (60% sensitivity, 47% specificity). In this study better results were obtained if an upper limit of normal of 50 u ml-1 was used for CA19-9 (75% sensitivity, 92% specificity). Combination of CA19-9 assay with the upper limit set at 50 u ml-1 and the peanut lectin assay improved the sensitivity to 85% with only a slight fall in specificity (85%). These results compare well with published results for ultrasound and CT scanning.

Adult↗