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D Drahovsky

Publications and source records attributed to D Drahovsky.

At least 55 records · Page 3Linked to original sources
PubMed1983

Enzymatic methylation of inverted DNA repeats in the vicinity of the mouse beta-major globin gene.

This paper examines the extent of enzymatic methylation in 5'-CCGG sequences of inverted repeats in DNA isolated from adult liver and bone marrow of DBA/2 mice, with special attention to the methylation of such sequences in the vicinity of the beta-major globin gene. Two thirds of inverted repeats contain 5'-AGCT and 5'-CCGG sequences, as found by a method based on the capability of inverted repeats of forming intramolecular duplexes under the conditions of "zero-time" reassociation. Methylation in internal cytosines of 5'-CCGG sequences of inverted DNA repeats differs between bone marrow and liver tissues. The beta-major globin gene was found in DNA covalently linked to inverted repeats. The enzymatic methylation of inverted repeats neighbouring the beta-major globin gene differs at HpaII recognition sites; the DNA of bone marrow tissue, in which this gene is expressed, is less methylated at such sites as compared to liver DNA.

Animals↗
PubMed1982

Inhibition of thymidylate synthase by hydroxyurea in rapidly proliferating P815 mastocytoma cells.

The incorporation of [14C]deoxycytidine, [3H]deoxyuridine, and [3H]thymidine, respectively into pyrimidine bases of DNA has been measured in rapidly proliferating P815 mouse mastocytoma cells in the presence of hydroxyurea. The incorporation of [14C]deoxycytidine-derived radioactivity into DNA cytosines is increased when compared to the incorporation into DNA thymines. The [3H]deoxyuridine-derived radioactivity is incorporated solely into DNA thymines and this incorporation is inhibited by hydroxyurea in a dose-dependent manner. This suggests an inhibitory effect of hydroxyurea on the thymidylate synthase which was proved in experiments in which the conversion of deoxyuridine monophosphate into deoxythymidine monophosphate catalysed by a crude enzyme preparation from P815 cells was inhibited in the presence of hydroxyurea. Enzymatic DNA methylation as measured by the conversion of incorporated [14C]deoxycytidine into 5-methylcytosines was not affected by hydroxyurea.

Animals↗
PubMed1982

Elevated level of enzymatic DNA methylation in cells treated with 1-beta-D-arabinofuranosylcytosine.

When mouse P815 mastocytoma cells are cultured in the presence of 1-beta-D-arabinofuranosylcytosine (ara-C), a dose-dependent inhibition of cell proliferation and DNA synthesis can be observed. The DNA synthesized in the presence of ara-C is more highly enzymatically methylated than that of controls as measured by conversion of incorporated [14C]deoxycytidine-derived radioactivity into 5-methylcytosines. Analysis of DNAs by means of the bacterial restriction enzyme HpaII and its isoschizomer MspI revealed an aberrant DNA methylation pattern after ara-C treatment. The hypermethylation of DNA persisted also in the cell cycle following the treatment in the absence of ara-C. No such changes in DNA methylation patterns following ara-C treatment were observed in P815/ara-C, a subclone of P815 cells resistant to ara-C.

Animals↗
PubMed1981

Hypomethylation of DNA in Raji cells after treatment with N-methyl-N-nitrosourea.

Human Raji lymphoblast-like cells were propagated in the presence of various concentrations of N-methyl-N-nitrosourea (MNU) and the degree of enzymatic methylation of newly synthesized DNA was analysed by two independent methods. The overall extent of enzymatic DNA methylation was measured on the basis of [14C]deoxycytidine derived radioactivity incorporated into DNA 5-methylcytosine and cytosine residues. Enzymatic methylation of internal cytosines at 5'-CCGG-3' sequences of Raji DNA was analysed by use of the bacterial restriction enzyme HpaII and its isoschizomer MspI. The data obtained by both methods indicate that the treatment with MNU causes a lower level of enzymatic methylation of newly synthesized DNA. This lower extent of DNA methylation persists in the absence of the carcinogen in the cell cycles following the treatment.

Burkitt Lymphoma↗
PubMed1981

[Peptide hormones LH, FSH, TSH, prolactin, beta-HCG and PTH in patients with urogenital tumors].

Serum levels of the peptide hormones, LH, FSH, TSH, prolactin, beta-HCG and PTH are observed to significantly modulate in patients with urogenital tumors, beta-HCG appears elevated in patients with chorioncarcinoma, teratoma and embryonal carcinoma and is shown to increase serum prolactin. TSH and prolactin are measured in pathological range in patients with renal carcinomas. Following nephrectomy serum TSH persists in high levels only in patients with advanced diseases, while PTH is more frequently suppressed in these patients. Serum LH and prolactin show a more distinct change of values in infiltrating bladder cancer, when compared to that of noninvasive bladder carcinomas. Prostate benign hyperplasia and cancer demonstrate similar ranges for peptide hormones, that will be changed by estrogen treatment in its LH, TSH and prolactin pattern. Serum levels of peptide hormones are affected by a complex system of ectopic hormone production, synthesis of peptide analogues, metabolic changes due to age and treatment.

Chorionic Gonadotropin↗
PubMed1981

Glycopeptides (FSH, LH, TSH, prolactin) and glycoproteins in patients with genitourinary cancer.

The present investigation has analyzed 249 patients suffering from urogenital cancer in respect to aberrant concentration of prolactin, TSH, LH and FSH. A simultaneous pattern of acute phase reactants (alpha 1-glycoprotein, alpha 1-antitrypsin, beta 2-glycoprotein and haptoglobin) was related to the content of these hormones. Abnormal results of prolactin and TSH were present in 30% of all patients, whereas frequent aberrations of alpha 1-acid glycoprotein and alpha 1-antitrypsin were detected in 60--80%. Acute phase reactants changed to more pathological values when correlated to elevated prolactin.

Adult↗
PubMed1981

Reevaluation of C-reactive protein in cancer sera by radioimmunoassay and radial immunodiffusion. I. Diagnostic value and use in battery of conventional tumor markers.

C-reactive protein (CRP) has been found to be ubiquitous in sera when determined by a highly sensitive methods such as radioimmunoassay. Patients with some tumors appear to have much higher serum levels of CRP than others; in these, CRP seems to reflect the tumor burden. There is a positive correlation with TNM staging and the disease activity a the time of determination. CRP shows a high degree of 'uniqueness' when correlated with other routinely used cancer markers such as carcinoembryonic antigen, placental-like alkaline phosphatase and gamma-glutamyltranspeptidase.

Alkaline Phosphatase↗
PubMed1981

Elevated transcriptional complexity and decrease in enzymatic DNA methylation in cells treated with L-ethionine.

This paper analyzes the extent of enzymatic methylation of DNA in P815 cells cultured for several cell cycles in the presence of 1 mM L-ethionine by use of the bacterial restriction enzymes HpaII, MspI, HhaI, HaeII, and AvaI. The results obtained suggest that the extent of methylation of DNA is decreased during L-ethionine treatment and that the degree of this inhibition varies among different methylation sites. The nucleotide sequence complexity of nuclear RNA in P815 cells was analyzed by excess hybridization with tracer amounts of nick-translated nonrepetitive P815 [3H]DNA sequences. About 6.2% of the nonrepetitive sequences form hybrids with nuclear RNA of controls cells, whereas 8.8% are complementary to nuclear RNA from L-ethionine-treated cells. Thus, the decrease in enzymatic DNA methylation correlates with the presence of new transcriptional products suggesting that this modification process inversely correlates with the initiation of transcription.

Animals↗
PubMed1981

[Clinical significance of peptide hormones LH, FSH, TSH, prolactin, HCG, parathormone, calcitonin and prostaglandin F2 alpha in kidney neoplasms].

Peptide hormones LH, FSH, TSH, e-peptide, prolactin, HCG, PTH, calcitonin and prostaglandin F2 alpha were evaluated in 25 patients with renal adenocancer. Prolactin elevation found in 45% was unrelated to the stage of the disease, while aberrant TSH and FSH were more sensitive in indicating distant metastasis. Prostaglandin F2 alpha, measured as a stable degradation product 13,14-DHK-PGF2 alpha, was frequently elevated and normalized following tumor nephrectomy within 12 month. Serum PTH was decreased in patients with tumor dissemination suggesting resorptive hypercalcemina, whereas none of the patient had circulating HCG levels. Therefore even patients without any paraneoplastic syndromes have a frequent change of peptide hormones directly or indirectly caused by renal cancer.

C-Peptide↗
PubMed1980

Enzymatic hypermethylation of DNA in mouse-mouse somatic cell hybrids.

Somatic cell hybrids between mouse L fibroblasts (A9 cells) and Ehrlich ascites tumour cells were constructed by use of poly(ethyleneglycol). The hybrids were selected in hypoxanthine/aminopterin/thymidine medium and morphologically different syncaryons were isolated by a micromanipulation. They were simultaneously analysed for their tumourogeneity, a release of certain proteins into the culture medium, the activity of pyrimidine salvage pathways, and the extent of enzymatic DNA methylation. None of these hybrids gave a rise of tumours if transplanted into DBA/2 mice. Two of the hybrids released a protein immunologically cross-reacting with antibody against C-peptide of human proinsulin. Activities of pyrimidine salvage pathways as measured by incorporation of [14C]deoxycytidine into DNA cytosine and thymine, respectively, are different in the analyzed cells. Enzymatic DNA methylation in somatic cell hybrids was significantly elevated as compared to the parental cell lines.

Animals↗
PubMed1980

C-peptide, testosterone, estrogen, cortisol and zinc in patients with benign hyperplasia of the prostate.

Patients with benign hyperplasia of the prostate (BHP) were studied in relation to aberrant serum c-peptide, testosterone, estrone, cortisol and morning fasting glucose, to analyze the syntropy of diabetes and BHP. The results were compared to patients with bladder cancer without BHP and, after correction of the patients' weights and ages, the control failed to prove any significance. This is consistent with the incidence rate of maturity onset diabetes in prostate adenomas (n = 527, 7.3%) and of a control group (8.5%) of patients, 60--70 years of age. Zinc, another parameter associated with insulin function, is frequently observed to change in BHP and is significantly increased in prostatic tissue which possibly acts as a zinc pool. In this study, however, no effect of prostatectomy on serum zinc was demonstrable even in a long-term control of 9 months, suggesting a sensitive and rapid regulation of this metal independent from the prostate.

Aged↗