Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to assess the potency of antigenic fragments of carcinoembryonic antigen (CEA) in the radioimmune assay; it is necessary to know whether the high affinity of goat anti-CEA antibody (which makes possible the detection of as little as 10--11M CEA) is due to bivalent binding of the CEA molecule. Immunoglobulin G and the F(ab')2 and Fab fragments derived from it were prepared from an anti-CEA serum and tested for their abioity to bind CEA. Equivalent concentrations of binding sites of the bivalent F(ab)2 and univalent Fab fragments of anti-CEA were identical to the immunoglobulin G fraction in the standard inhibition curve. Fragments of CEA obtained by trypsin digestion produced equivalent inhigition curves when tested with either immunoglobulin G, F(ab')2, or Fab". This, increased avidity due to bivalent binding to a single antigen molecule cannot be invoked to explain the sensitivity observed in the CEA assay. This high sensitivity implicates the protein rather than the carbohydrate as an important part of the antigenic determinant(s) of CEA.
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PMID:The binding of carcinoembryonic antigen by antibody and its fragments. 4 22

Biochemical characterization of serologically detected human melanoma antigens was undertaken for the development of immunodiagnostic assays in melanoma. An antiserum from a human melanoma patient, which detected melanoma antigens expressed on a large proportion of different melanoma cells, was used in leucocyte-dependent cytotoxic antibody (LDA) 51Cr-release assays to monitor the purification of melanoma antigens in urea/acetate extracts of lactoperoxidase 125I-labelled melanoma cell membranes. The separation procedures included affinity chromatography on Concanavalin A, gel filtration on porous polyacrylamide beads and preparative isoelectric focusing. The fractions were also monitored by polyacrylamide electrophoresis in sodium dodecyl sulphate and by measurement of beta 2 microglobulin and carcinoembryonic antigen content. The antigens detected by this antiserum appeared to be acidic (pI 3.5) low-mol.-wt glycoproteins of approximately 15,000 daltons which were resistant to heating at 56 degrees C and digestion with neuraminidase, but susceptible to repeated freeze-thawing and trypsin digestion. They did not appear to be related to HLA antigens, beta 2 microglobulin or known foetal antigens. The nature of the antigens detected in these studies is as yet unknown, but they appear similar to those described in the sera and urine of melanoma patients in previous reports. Thes combined results and the frequent expression of these antigens on melanoma cells from different patients suggest that assays to detect this antigen may provide a valuable immunodiagnostic aid in the management of melanoma.
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PMID:Detection of a low-molecular-weight antigen on melanoma cells by a human antiserum in leukocyte-dependent antibody assays. 9 79

An ovarian cystadenocarcinoma-associated antigen (OCAA) was found to be common to all serous and mucinous cystadenocarcinomas of the ovary. It was apparently absent in tissues of normal reproductive organs. Furthermore, OCAA was not detected in benign ovarian serous and mucinous cyst-adenomas or in any other gynecologic or nongynecologic cancers thus far tested. The antigenic determinant of OCAA was immunologically unrelated to the carcinoembryonic antigen, other known tumor antigens, or the histocompatibility antigens. We purified and partially characterized OCAA. The antigen was a high-molecular-weight glycoprotein soluble in 0.6 M perchloric acid. It consisted of about 50-60% protein (based on dry wt). Amino acid composition in OCAA was characterized by a high percentage of threonine, serine, proline, and valine. Galactose and N-acetylglucosamine were the principal carbohydrate constituents. The antigenic activity was resistant to treatment with trypsin and protease and also to treatment with DNase, RNase, and N-acetylneuraminidase. The antigenicity was considerably reduced by mild periodate oxidation.
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PMID:Tumor-associated antigen for cystadenocarcinomas of the ovary. 82 81

We undertook to test the recent suggestion that measurement of immunoreactive carcinoembryonic antigen (CEA) in pancreatic secretion may be useful in diagnosis of pancreatic cancer. Using duodenal intubation and a perfusion method in 57 cases, we measured the rate of pancreatic CEA secretion into the duodenum under basal saline perfusion, alone and with continuous intravenous infusion of secretin (2 clinical units per kg per hr) and of cholecystokinin-pancreozymin (CCK, 15 Crick-Harper-Raper units per kg per hr); and we compared the CEA output with secretion of trypsin, lipase, and bicarbonate under the same conditions. Subsequent laparotomy revealed pancreatic carcinoma in 25 patients, pancreatitis in 7, other intraabdominal malignancies in 6, and benign nonpancreatic disorders in 19. CEA output rates did not differentiate all pancreatic-cancer patients from other patients in any test condition. However, pancreatic enzyme outputs were abnormal with almost 90% of cancers of the pancreatic head and with 75% of cancers of the pancreatic body and tail. For detection of pancreatic cancer, enzyme and bicarbonate outputs in response to CCK are more accurate than pancreatic CEA or bicarbonate outputs in response to secretin. Since CCK-stimulated enzyme outputs can be related accurately to malabsorption (not reported here), we prefer them to bicarbonate output for assessment of pancreatic function.
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PMID:Prospective evaluation of the pancreatic secretion of immunoreactive carcinoembryonic antigen, enzyme, and bicarbonate in patients suspected of having pancreatic cancer. 89 42

The normal pancreas consists of three major cell types or lineages that share a common embryologic origin from pluripotent endodermal precursors. The type of cell that undergoes neoplastic transformation to form a pancreatic carcinoma is controversial and may influence the phenotype and biologic behavior of the tumor. In this study, immunohistologic techniques were used to determine the cell lineage differentiation expressed in 29 primary exocrine pancreatic adenocarcinomas, five metastatic exocrine pancreatic adenocarcinomas, and five islet cell neoplasma. Specimens of normal pancreas and chronic pancreatitis were used for comparison. The cell lineage markers consisted of monoclonal and polyclonal antibodies against trypsin and lipase (acinar cells); secretory component, carbonic anhydrase II, and pancreatic cancer mucin SPan-1 (ductal cells); and chromogranin-A and somatostatin (islet cells). The expression of carcinoembryonic antigen (CEA) and lysozyme were also determined. This collection of markers allowed the differentiation between acinar, ductal, and islet cells of normal pancreas and chronic pancreatitis specimens. The expression of cell lineage markers in islet cell tumors was homogeneous and restricted to chromogranin-A. In contrast, the expression of these markers in primary and metastatic exocrine pancreatic adenocarcinomas was variable. Reactivity with monoclonal anti-CEA was absent in normal pancreas, and was present in 83% of chronic pancreatitis specimens as well as 90% of exocrine pancreatic adenocarcinomas. In addition, lysozyme reactivity was absent in normal pancreas; however, lysozyme was expressed in one case of chronic pancreatitis, 17 cases of primary carcinoma, and three cases of metastatic carcinoma. These findings support the concept that the original transformed cell type in many pancreatic exocrine carcinomas resemble endodermal "stem cells" that retain the capability of differentiation along more than one cell lineage pathway.
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PMID:Cell lineage markers in human pancreatic cancer. 222 68

A human hepatocellular carcinoma (HCC) cell line (KYN-1) has been established from a resected HCC of a 58-yr-old Japanese, male patient with HCC. Original resected HCC was moderately differentiated and proliferated in a solid pattern with vague trabecular structure in part. This cell line has been maintained for 10 mo. through 50 passages. Morphological features of KYN-1 cells demonstrated one or more large, round-to-oval nuclei with prominent nucleoli and eosinophilic polygonal-to-spindle abundant cytoplasm. In addition, some of these cells contained mucicarmin-positive materials in the cytoplasm. The cells exhibited a typical epithelial feature with pavementlike cell arrangement, and lacked contact inhibition. The doubling times of the cells grown in a serum-containing and a serum-free medium were about 31 h and 10 to 11 d, respectively. Functionally, KYN-1 cells produced albumin, alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), ferritin, beta 2-microglobulin (BMG), and alpha 1-anti-trypsin (AAT). Positive reactions for albumin, AFP, CEA, and ferritin were identified in the cells by immunohistochemical techniques. Chromosome study revealed the chromosome number in a range from 61 to 74 without mode. The tumorigenicity of KYN-1 cells was identified by the tumor formation after subcutaneous inoculation of the cells into nude mice. The developed tumor showed compact growth of the tumor cells with gland formations containing mucicarmin-positive materials. Features of adenocarcinoma were identified by electron microscopy. The tumor cells were also identified to contain albumin, AFP, CEA, ferritin, and AAT by immunohistochemical techniques. AFP, CEA, and BMG were detected in the sera of nude mice. Thus, KYN-1 cells represented the morphologic features of adenocarcinoma, retaining some characteristics of original HCC. These findings suggest that KYN-1 is a new human HCC cell line with transformation to adenocarcinoma, which will provide useful information to clarify the histogenesis of combined hepatocellular and cholangiocellular carcinoma.
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PMID:A new human hepatocellular carcinoma cell line (KYN-1) with a transformation to adenocarcinoma. 243 Sep 33

The cellular sediments of 42 malignant and 16 benign effusions (58 cases) were studied using the immunoperoxidase technique. Serial sections of formalin-fixed, paraffin-embedded residual sediments of effusions, sent for routine cytologic examination, were studied by commercially available polyclonal antisera against lysozyme, alpha 1-anti-trypsin, alpha 1-anti-chymotrypsin, tissue polypeptide antigen (TPA), a wide-spectrum anti-keratin, carcinoembryonic antigen (CEA) and, in single cases, thyroglobulin and prostate-specific antigen. A final definite diagnosis from histologic study of biopsy or autopsy specimens was known in all cases. All carcinomas, the mesotheliomas and the reactive mesothelial cells showed a positive reaction for TPA and, partly, the wide-spectrum keratin. Lysozyme could be demonstrated in the cells of the one proven malignant fibrous histiocytoma; all malignant epithelial cells were negative. Alpha 1-anti-chymotrypsin and alpha 1-anti-trypsin showed similar reactions: they were often positive in carcinoma cells of the breast, the bronchial system and the pancreas, in contrast to a mostly negative reaction in carcinomas of the stomach and ovary. CEA showed considerable differences; it was always negative in benign and malignant mesothelial proliferations but mostly positive in carcinomas of the stomach, pancreas and bronchial system. It was only positive in less than 20% of the carcinomas of the breast and always negative in the proven malignant effusions of primary carcinomas of the ovary and prostate. Studying a combination of several tumor markers is possible in serial paraffin-embedded sections and may be a valuable criterion in the cytologic diagnosis of effusions.
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PMID:Immunohistochemical study of lysozyme, alpha 1-anti-chymotrypsin, tissue polypeptide antigen, keratin and carcinoembryonic antigen in effusion sediments. 243 1

Immunoperoxidase stains were performed on normal and neoplastic tissue from prostate, colon, thyroid, lung, nerve, uterus, and placenta embedded in both plastic (glycolmethacrylate [GMA]) and paraffin. Positive results in plastic section were obtained for carcinoembryonic antigen (CEA), keratin, epithelial membrane antigen (EMA), thyroglobulins, S-100, prostate-specific antigen, human chorionic gonadotrophin (HCG), and beta-HCG. More delicate staining with more precise localization of antigens is noted. Superior (paraformaldehyde) fixation and cold processing followed by GMA polymerization (4 degrees C) allow for optimum antigen survival. After fixation, tissue processing involves a series of 0.1 mol/L phosphate buffer rinses with sucrose and ammonium chloride in a conventional dip-and-dunk processor placed in a 4 degrees C cold room. Acetone dehydrations are used before GMA infiltration, cold polymerization, and sectioning. Before immunoperoxidase staining, the plastic section is digested in .25% bovine trypsin for ten minutes. The immunoperoxidase methods described can be useful when small biopsies are routinely embedded in plastic to obtain improved histologic (hematoxylin-eosin) sections. There may also be research applications in quantifying antigen expression in benign, dysplastic, and neoplastic tissues by examining the stains under high power.
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PMID:Antigen localization in immunoperoxidase-stained plastic-embedded soft tissues. 245 78

A panel of 17 monoclonal antibodies (MAbs), which are reactive with purified carcinoembryonic antigen (CEA), was tested. The MAbs were categorized into 6 groups according to their reactivity with CEA 180, CEA 160, non-specific cross-reacting antigen (NCA) 97 and NCA 50. After chemical modification of CEA (reduction, carboxymethylation, deglycosylation, enzymatic cleavage) and binding studies, the MAbs were further divided into 8 subgroups, representing 8 different antigenic sites on CEA. All MAbs bind to deglycosylated CEA. Most of the MAbs are directed against conformational determinants, since only three of them recognize reduced and alkylated CEA. The same three MAbs are able to detect 29 kDa glycosylated fragments obtained by enzymatic cleavage of CEA. These three protease V8- and trypsin-resistant fragments, probably obtained by interdomain cleavage, show a close relationship in peptide patterns, supporting the repeating structural domain-model of CEA as deduced from the cDNA sequence of CEA.
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PMID:Analysis of the specificity of CEA reactive monoclonal antibodies. Immunological support for the domain-model of CEA. 246 81

Microwave (MW) energy permits rapid tissue fixation for light and electron microscopy but its effects on antigen preservation have not been fully evaluated. We, therefore, fixed three samples of human skin, uterus, and cervix, and two samples of human colon and breast by MW irradiation (5 to 8 seconds) during simultaneous immersion in a dilute aldehyde mixture (2% formaldehyde and 0.05% glutaraldehyde). For comparison, similar portions of each specimen were fixed in formalin. Specimens were processed routinely and embedded in paraffin for light microscopy. Sections from each specimen were stained with hematoxylin and eosin and, by immunoperoxidase techniques, for epithelial membrane antigen, leukocyte common antigen, S-100 keratin, carcinoembryonic antigen, and factor VIII-related antigen, the latter three with and without preliminary trypsinization. Colon sections were also stained for chromogranin. In all cases, light microscopic morphology was comparable for tissues fixed by the MW method and formalin-fixed specimens, as was immunostaining for epithelial membrane antigen, leukocyte common antigen, S-100 protein, and chromogranin. Formalin-fixed tissues required trypsinization for optimal detection of keratin, carcinoembryonic antigen, and factor VIII-related antigen. In contrast, trypsin-pretreatment was not necessary to demonstrate these antigens in MW-fixed specimens and, in fact, resulted in tissue digestion. We conclude that this MW fixation method provides a means for rapidly fixing tissues for immunoperoxidase staining while preserving excellent light microscopic morphology.
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PMID:Rapid microwave fixation of human tissues for light microscopic immunoperoxidase identification of diagnostically useful antigens. 331 39


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