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Biomedical subjects

V Dufek

Publications and source records attributed to V Dufek.

At least 37 records · Page 2Linked to original sources
PubMed1985

Changes in serum cathepsin B-like activity in patients with colorectal cancer.

Cathepsin B-like activity (CB-like) was estimated in sera of 30 male patients with colorectal cancer (n = 20), benign polyps of the rectum (n = 10) and in sera of control subjects (n = 50). Both total and residual activities of the enzyme in colorectal cancer patients showed a significant elevation in comparison with control subjects and patients with benign polyps. In the course of antitumor therapy a decline in catheptic activity was observed when a reduction in the volume of tumor tissue was present. On the other hand, an increment in CB-like activity was observed when antitumor therapy had no effects or tumor relapse was present.

Cathepsin B↗
PubMed1985

Changes in tissue and serum activity of cathepsin B-like cysteine proteinase during colorectal carcinogenesis by 1,2-dimethylhydrazine in mice.

The activity of cathepsin B-like cysteine proteinase in the mice colon was studied during carcinogenesis induced by 1,2-dimethylhydrazine dihydrochloride (DMH). Before starting the treatment with DMH, the activity of the observed enzyme was very low in the colorectal area but the activity in the serum was rather high. In the course of carcinogenesis, the local activity markedly increased in the stroma equally as in the cells of developing tumors while the serum activity slightly decreased. Following the total ovariectomy, no significant changes in the local activity or in the serum activity were found. Possible causes of these variations are discussed.

1,2-Dimethylhydrazine↗
PubMed1984

Serum alkaline-stable acid thiol proteinase--a possible marker for primary liver carcinoma.

Activities of alkaline phosphatase (ALP), gamma-glutamyl transferase (GMT), lactate dehydrogenase (LD), beta-glucuronidase (GLU) and cathepsin B-like (CB-like) were determined in blind-coded sera from 50 patients with primary liver carcinoma, liver cirrhosis and acute hepatitis, and from 40 control subjects of comparable age range. CB-like activity averaged 700% (p less than 0.01), 1590% (p less than 0.01) and 1600% (p less than 0.01) of control subjects in liver cirrhosis (n = 30), acute hepatitis (n = 5) and primary liver carcinoma (n = 15), respectively. In acute hepatitis group we have found significant correlation between CB-like and GLU activities (r greater than 0.95). This correlation, however, was not observed in primary liver carcinoma suggesting that alteration in CB-like activity is not due to generalized increases in lysosomal membrane instability. The primary liver carcinoma group exhibited also the modest increments in serum ALP, GMT and LD activities (p less than 0.01). This increment, however, was not detected in any of acute hepatitis or liver cirrhosis patients. For the first time the alkaline-stable form of CB-like in human serum is described. This form representing 40% of overall CB-like activity was present in all primary liver carcinoma patients. This form, however, was not present in sera of any of control subjects or in sera of patients with acute hepatitis and liver cirrhosis with the exception of two men, in whom we have probably dealing with an early stage of primary liver carcinoma. Although the nature of the increment in CB-like activity in cancer remains to be determined, such analyses may help to the early detection of malignant hepatoma (primary liver carcinoma).

Aged↗
PubMed1984

Characterization of cathepsin B-like proteinase from ascitic fluid of patients with primary liver cancer.

Ascitic fluid of patients with primary liver cancer was shown to contain a latent thiol proteinase which can be activated by pepsin treatment or by autolysis at acidic environment. This enzyme resembles cathepsin B (EC 3.4.22.1) in many physical-chemical properties including substrate specificity, requirement for thiol activators and inhibition both by thiol blocking reagents and by peptidyl diazomethyl ketones, but has a higher molecular size even after activation. Pepsin treatment and autolysis reduce its Mr from 41 800 to 33 400 and 27 700, respectively, but all these forms are larger than human liver cathepsin B. The latent enzyme may be, therefore, an enzyme--inhibitor complex or an inactive precursor of cathepsin B due to an altered processing in Golgi endoplasmatic reticulum-lysosome compartment.

Ascitic Fluid↗