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Biomedical subjects

A Sedo

Publications and source records attributed to A Sedo.

29 records · Page 2Linked to original sources
PubMed1992

Two-step generation of spirocyclic dipeptides from linear peptide ethyl ester precursors.

Linear tri- and tetrapeptide precursors of 2,5-piperazinedione were prepared and their conversion to spirocyclic dipeptidase enzymes, the spirocyclic dipeptides (SpDp) were generated from the precursors by a two-step mechanism consisting in the proteolytic release of the C-terminal dipeptide ethyl ester and its subsequent spontaneous cyclization. After intraperitoneal administration of urokinase and Ac-Leu-Lys-Gly-Acp-OEt, a SpDp precursor targeted to endogenous plasmin, or the administration of the activated Hageman factor fragment and Ac-Leu-Arg-Ala-Acp-OEt, a SpDp precursor, targeted to endogenous kallikrein, the generated corresponding C-terminal dipeptide ethylester intermediates and SpDp, cyclo(Gly-Acp) and cyclo (Ala-Acp), respectively, were detected in the blood serum of C57B1 mice. Suppression of partial amnesia induced by sodium nitrite was observed in rats where it was subcutaneously administered with H-Leu-Ala-Acp-OEt, a peptide precursor of alaptide, the active SpDp, i.e. cyclo(1-amino-1-cyclopentanecarbonyl-L-alanyl).

Amino Acid Sequence↗
PubMed1991

Dipeptidyl peptidase IV, prolyl endopeptidase and cathepsin B activities in primary human lung tumors and lung parenchyma.

The activities of dipeptidyl peptidase IV (DPP-IV), prolyl endopeptidase (PE) and cathepsin B (CB) were investigated in primary human lung tumours and matched lung parenchyma, using continuous-rate fluorometric assays of the enzymes. Squamous-cell lung carcinomas showed significantly higher specific activities of all three enzymes studied. In lung adenocarcinomas only activities of PE and CB were increased significantly. In a limited number of primary human lung tumours of other histological types the activities of DPP-IV, PE and CB were also elevated. Mixing the matched homogenates of lung tumours and lung parenchyma gave additive activities for each enzyme studied. A significant correlation between tumour/lung ratios of specific activities of DPP-IV and CB was observed.

Adenocarcinoma↗
PubMed1991

Aminopeptidases and angiotensin I-converting enzyme activities in primary human lung tumors and lung parenchyma.

The activities of alanyl aminopeptidase (AAP), arginyl aminopeptidase (RAP), alpha-glutamyl aminopeptidase (EAP) and angiotensin I-converting enzyme (ACE) were investigated in primary human lung tumors of different histological types and in matched lung parenchyma. In contrast to the studied aminopeptidases whose activity differences between tumor and lung tissues were infrequently significant, the activity of ACE was decreased highly significantly in the majority of lung tumors.

Adenocarcinoma↗
PubMed1991

Dipeptidyl peptidase IV in the human lung and spinocellular lung cancer.

The isoelectric point and proportions of soluble and membrane bound dipeptidyl peptidase IV (DPP-IV) in human lung and spinocellular lung cancer tissue were tested. It was found that soluble DPP-IV is relatively less frequent in the cancer than in normal lung tissue. We demonstrated multiple molecular forms of DPP-IV in normal and cancer lung tissues, differing probably not only in the degree of sialylation. DPP-IV from lung cancer tissue consists of more basic molecular forms than that from normal lung tissue. These results suggest that the molecular properties of DPP-IV in normal and cancerous lung tissues may be different.

Carcinoma, Squamous Cell↗
PubMed1989

A kinetic fluorometric assay of dipeptidyl peptidase IV in viable human blood mononuclear cells.

A continuous-rate fluorometric assay of dipeptidyl peptidase IV (DP-IV) in viable human blood mononuclear cells using 7-(L-glycyl-L-prolylamido)-4-methylcoumarin as the substrate is described. The assay method is accurate, rapid, and highly sensitive for measuring the level of cell-surface bound DP-IV activity in suspension of blood mononuclear cells, as well as of other viable cells bearing this enzyme. We believe that the kinetic assay is suitable for studying the regulation of expression and the role of plasma membrane-bound DP-IV on the cellular level.

Cell Separation↗
PubMedDate not supplied

Detection of cell type and marker specificity of nuclear binding sites for anionic carbohydrate ligands.

The emerging functionality of glycosaminoglycan chains engenders interest in localizing specific binding sites using cytochemical tools. We investigated nuclear binding of labeled heparin, heparan sulfate, a sulfated fucan, chondroitin sulfate, and hyaluronic acid in epidermal keratinocytes, bone marrow stromal cells, 3T3 fibroblasts and glioma cells using chemically prepared biotinylated probes. Binding of the markers was cell-type specific and influenced by extraction of histones, but was not markedly affected by degree of proliferation, differentiation or malignancy. Cell uptake of labeled heparin and other selected probes and their transport into the nucleus also was monitored. Differences between keratinocytes and bone marrow stromal cells were found. Preincubation of permeabilized bone marrow stromal cells with label-free heparin reduced the binding of carrier-immobilized hydrocortisone to its nuclear receptors. Thus, these tools enabled binding sites for glycosaminoglycans to be monitored in routine assays.

3T3 Cells↗
PubMedDate not supplied

Detection of dipeptidyl peptidase IV in glioma C6 and neuroblastoma SK-N-SH cell lines.

The dipeptidyl peptidase IV (DPP-IV) activity of the rat glioma cell line C6 and the human neuroblastoma cell line SK-N-SH was investigated. DPP-IV fluorescent substrate was cleaved by both cell lines. The pH reaction optimum determined was typical for DPP-IV described in other cell models. The reaction was inhibited by specific inhibitors diprotins A and B. Enzyme activity was localized, both on the cell surface and intracellularly. Most of the DPP-IV activity was membrane bound. However, soluble intra-cellular activity was found in both cell lines. Secreted activity was not detected in either cell line. In the C6 line, but not in the SK-N-SH line, we demonstrated depression of the ratio of cell surface to total cell DPP-IV activity at higher cell densities, indicating possible enzyme redistribution during cell growth in culture. Identification of DPP-IV activity is the first step in our study of the role of DPP-IV in the neural system.

Animals↗