[Level of endothelial vasodilatation and activity of angiotensin converting enzyme as criterion of efficacy of therapy in patients with mild and moderate hypertension].
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Adult↗
Biomedical subjects
E A Dilakian
Publications and source records attributed to E A Dilakian.
[Comparative study of acid SH-dependent proteinases from the swine renal cortex].
The presence of porcine kidney cortex of the SH-dependent enzymes, lysosomal carboxypeptidase B and cathepsins B, H and L, was demonstrated. A method for isolation of these enzymes was described which involves gel filtration through Sephadex G-100, covalent chromatography on mercury-organic Sepharose 4B and rechromatography on Sephadex G-100. Specific activity of lysosomal carboxypeptidase B was increased 9000-fold by BAA splitting and that of cathepsin B 240-fold by BAPA splitting. The molecular weights of lysosomal carboxypeptidase B and cathepsin B were found to be 50,000 and 26,000, respectively. Both enzymes were identical with appropriate enzymes obtained from other sources and differed in their properties from high-molecular-weight SH-proteinase or porcine kidney cortex.
Animals↗
[Limited proteolysis of integrin alpha v beta3 from human placenta].
Purification of alpha v beta 3 integrin from human placenta with successive usage of two affinity sorbents--immobilized monoclonal antibodies to alpha v beta 3 integrin and immobilized RGD-containing decapeptide allowed to purify this integrin's partially degraded fraction, that was nevertheless able to interact with its ligand. During the incubation of partially degraded alpha v beta 3 integrin at 37 degrees C its further degradation went on. Addition of serine proteinase inhibitors: (phenylmethilsulfonyl fluoride, leupeptin and aprotinin) completely suppressed integrin further degradation of alpha v beta 3. In preparations of intact and partially degraded alpha v beta 3 integrin specific activity of two serine proteinases--urokinase and dipeptidilpeptidase IV--was discovered. alpha v beta 3 integrin, undergoing limited proteolysis, had lesser affinity towards RGD peptide, that intact integrin. The results show, that alpha v beta 3 integrin from human placenta co-purifies with serine proteinases. It is suggested that a definite part of functionally active alpha v beta 3 integrin, extracted from human placenta by triton X-100, forms a stable complex with serine proteinases.
Female↗
[Type I and IV collagenases and their endogenous regulators in immortalized and transformed fibroblasts].
To elucidate the role of matrix metalloproteinases (MMP) in carcinogenesis, the expression of collagenases of types I (MMP-I) and IV (MMP-2 and MMP-9) as well as the behaviour of urokinase-like plasminogen activator (uPA) and of tissue MMP inhibitors (TIMP) in immortalized (IF) and transformed (TF) fibroblasts were investigated. The study was carried out using embryo rat fibroblasts, sequentially immortalized with the LT gene of human papilloma virus and transformed with the E7 gene of human papilloma virus (HPV-16). As control was used the primary fibroblast (PF) culture of Fisher rats. In IF, the collagenase activity was at the same level as it was in PF. The activity of uPA in IF was increased by 2-2.5-fold; the titrated amount of free endogenous inhibitors in IF and PF was at essentially the same level while being markedly higher than in TF. At the stage of fibroblast transformation with the E7 gene of HPV-16, there was seen an increase of Type IV collagenases and a decrease of Type I collagenase, both these indices being most pronounced in the cells with most developed tumorigenic properties. In TF there occurred a decrease of free endogenous MMP inhibitors relative to the enzyme activity and, at the same time, a decrease in uAF activity, indicating the changes occurring in the enzyme/inhibitor/activator ratio and hence the enhancement of the destructive potential of the cells (in this case, at the cost of Type IV collagenase activity).
Animals↗
[ACE-dependent and sympathetic components of blood pressure regulation in patients with essential hypertension].
UNLABELLED: The development of arterial hypertension is accompanied by impairment of the normal ratio of the "ACE-depending" and of the sympathetic nervous system, correlates with the action on the main pharmacological "targets": I-I-imidazoline receptors (moxonidine) or the ACE activity (enalapril). The aim of the present investigation was to determine the hypotensive and metabolic effects of moxonidine and enalapril depending on the basal ACE activity in patients with arterial hypertension, complicated with the metabolic syndrome. Effectiveness of moxonidine and enalapril administration (during 24 weeks) depended on the basal ACE activity in the hypertensive patients: (a) in the group of patients with low basal ACE activity moxonidine very effectively decreased systolic and diastolic blood pressure, compared with the group of patients with high basal ACE activity; (b) influence of enalapril on the level of arterial blood pressure was more pronounced with high basal ACE activity. IN CONCLUSION: choosing a hypotensive treatment for patients with the metabolic syndrome, it is advisable to take into account the basal ACE activity levels.
Adult↗
[Characterization of cysteine proteinase endogenous inhibitors obtained from transformed fibroblasts].
The thermostable endogenous cysteine proteinase inhibitors (CPI) from the primary (REF), immortal (clone IE5) and transformed (clones trF8 and trF8nmcc) fibroblasts were isolated. All the isolated CPI act as reversible competitive inhibitors of cathepsins B and L and of papain. The study of inhibition of cathepsins B and L, purified from the same cell cultures as the CPI, showed that the Ki values for CPI from the cultures of immortal and transformed cells were by one order higher than the Ki values for CPI of primary fibroblasts. The data obtained suggest that immortalization and transformation alter the CPI properties.
Animals↗
[Lysosomal cysteine proteinases at neoplastic transformation].
This review summarizes the data on classification, properties, structure and biological functions of mammalian papain-like lysosomal cysteine proteinases (cathepsins). The most studied are cathepsins B, H, L, S and K. The peculiarities of lysosomal cysteine proteinase regulation, particularly regulation by specific endogenous inhibitors are discussed. Involvement of these enzymes in development of physiological and pathological processes are considered. Special attention is paid to the role of cysteine proteinases and their inhibitors in neoplastic transformation. The possibility of use cathepsin endogenous inhibitors as basis for design antitumorogenic therapeutic substances are discussed.
Animals↗
[Cysteine proteinases at various stages of neoplastic transformation of rat fibroblasts].
Cysteine-dependent proteinases were studied in a model system of rat embryonal fibroblasts which enabled to evaluate two discrete steps of malignant transformation in vitro: immortalization and tumoral transformation. Dynamics of intracellular and secreted activities of cysteine proteinases was estimated in relation to the stage of transformation and duration of cells cultivation. Activation of cysteine proteinases cathepsins L and B correlated with developed transformation of fibroblasts; each step of the process was characterized. Intracellular and secreted activities of the proteinases were distinctly increased in immortalized cells as compared with primary fibroblasts. The highest activity of the enzymes was detected both in intra- and extracellular fractions at the stage of complete fibroblast transformation. Cysteine-dependent cathepsin L-like proteinase was mainly responsible for intracellular and secreted activities of the fibroblast cultures studied. This proteinase was found to be produced in the form of precursor in all the cell strains studied and/or main part of the enzyme developed complexes with an inhibitor.
Adenoviruses, Simian↗
[The use of various fluorogenic substrates for determining peptide hydrolase activity of the blood serum].
4-methoxy-beta-naphthylamide and 7-amino-4-methyl coumarin, derivatives of Z-Ala-Arg-Arg, Leu- and Gly-Phe-beta-naphthylamides were used as substrates in estimation of peptide hydrolases activity in blood serum of patients with malignant tumors and glomerulonephritis in order to ascertain their efficiency for diagnostic purposes in clinic. Each of the fluorogenic substrates studied was hydrolyzed by various peptide hydrolases from blood serum both under normal and pathological conditions: metallopeptidases, cysteine- and serine-dependent peptide hydrolases. The rate of Z-Ala-Arg-Arg-MNA hydrolysis was decreased in lung, kidney and ileum cancer as well as in glomerulonephritis as compared with normal state. The "alkaline-resistant" cysteine-dependent cathepsin B-like proteinase, hydrolyzing this peptide, was not detected in blood serum neither in normal state nor in these diseases studied. Leu-NA and Gly-Phe-NA were hydrolyzed most effectively in blood serum of patients with lung cancer and glomerulonephritis as compared with normal state; cysteine-dependent peptide hydrolases were most markedly activated. Alterations in the enzymatic activity, detected in blood serum, did not exhibit any specificity for definite diseases, they were observed both in malignant and inflammatory impairments. The data obtained suggest that the fluorogenic substrates studied could not be suitable for clinico-diagnostic purposes.
Clinical Enzyme Tests↗
[Characteristics of cysteine peptidohydrolases from the human kidney cortex].
Spectrum of cysteine peptide hydrolases was studied in human kidney cortex using a variety of protein and synthetic substrates after the preparation was fractionated on Sephadex G-100 following the precipitation with ammonium sulfate 40-70%. Activities of dipeptidyl aminopeptidase I, lysosomal carboxypeptidases A and B, cathepsins B and H, as well as the activity of Ca+2-dependent neutral proteinase were detected. A thiol-dependent proteolytic activity, which was apparently stimulated by cathepsin T- and -M like enzymes, was also observed. Besides, the proteinase with molecular mass of 50-60 KDa and high hemoglobin and casein splitting activity was found. This activity cannot be attributed to any of the proteinases so far known. Isoelectrofocusing technique showed that two forms of cathepsin B occurred in human kidney with isoelectric points at pH 5.32 and pH 5.65; two forms of cathepsin H were also detected exhibiting isoelectric points at pH 6.03 and pH 6.7.
Chromatography, Gel↗
[Thiol peptide hydrolases from animal tissues, their structure and function].
Data on properties, structure and biological functions of a variety of thiol (cysteine) peptide hydrolases from animal tissues have been summarized. This large group of diverse intracellular enzymes involves both endo- and exopeptidases. Best studied are lysosomal thiol peptide hydrolases: cathepsins B, H and L, the primary structure of which is deciphered. They present a family of homologous proteins, structurally similar to papain. Ca2+-dependent neutral proteinases is another family of related proteins. The biological functions of various thiol peptide hydrolases are considered: their participation in protein turnover, post-translational processing, regulation of unidirectional biological processes and metabolic refolding. Data on endogenous inhibitors of thiol peptide hydrolases and on regulation of enzymic activity are presented.
Amino Acid Sequence↗
[Purification and some characteristics of 2 acid cathepsins from porcine kidneys].
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Amino Acids↗
[Comparative study using dansyl-peptide maps of the substrate specificity of 2 acid proteinases from porcine kidney].
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Animals↗
[Expression of cathepsins D and L during neoplastic transformation of fibroblasts].
Study of the expression of the aspartyl cathepsin D-like and cysteine cathepsin L-like proteinases was carried out on a model system of rat embryo fibroblasts. The model system employed makes it possible to distinguish two discrete successive stages of transformation in vitro: immortalization and tumorigenic transformation. The dynamics of expression and subcellular distribution of proteinases throughout the transformation process was followed. It was shown that in immortalized and transformed cells the activities of the aspartyl and cysteine proteinases were expressed to a variable degree and the expression was dependent on the time of cell cultivation. The increase in both the aspartyl cathepsin D-like proteinase and cysteine cathepsin L- and B-like proteinase activities was correlated with the stage of fibroblast transformation. At all stages studied of transformation, the major part of cathepsin L-like proteinase activity was localized within the cell, while among secreted proteinases the cathepsin D-like proteinase was apparently predominant. It was found that the secreted cathepsin D-like proteinase in all cell cultures studied was complexed with the inhibitor.
Animals↗
[Cathepsins L and B and their endogenous inhibitors in embryonal fibroblasts transformed by different genes].
Expression of cysteine proteinases, cathepsins L and B, and their inhibitors was studied out in three model systems of rat embryo fibroblasts, sequentially immortalized and transformed by different genes. In Model I rat embryo fibroblasts were immortalized with DNA of early region of simian adenovirus SA7 (clone REF-1) and then transformed by c-Ha-ras oncogene (REF-2EJ; malignant transformation). In Model II and III, the immortalized fibroblasts (clone IE5) were obtained by transfection with the polyoma virus LT gene and the clone IE5 used lost this gene; the malignant transformation was achieved by transfection with the E7 gene (clone trF8; Model II) and E6/E7 genes ¿clone A5E5(pC7-1); Model III]¿ of human papilloma virus types 16 and 18 respectively. In Model I, the increase in the total cathepsin L and B activity was correlated with the stages of transformation, at the same time, in Models II and III, this activity in immortalized IE5 fibroblasts was higher than at transformation stage. The activity of cathepsin L in lysates of transformed fibroblasts--REF-2EJ, significantly exceeded this activity both in transformed cells trF8 and A5E5(pC7-1)(6- and 10-fold, respectively). In cell cultures of Models I and II, the increases in secreted activity of cathepsins L and B were correlated with the stages of fibroblasts transformation, but in cultures of Model III, this activity at the stage of malignant transformation was lower than that the stage of immortalization. Therefore, the activities of cathepsins L and B were expressed to varying degrees at different stages of oncogenic transformation and the expression of their activities were dependent on type of transforming gene. It was established that changes in proteolytic potential were correlated with differences in the transforming phenotype of cell clones. An endogenous inhibitor(s) of cysteine proteinases was found in conditioned media of all type cell cultures. Expression and inhibitory properties of this inhibitor(s) were different at distinct stages of transformation.
Adenoviridae↗