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Objective: Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are present in esophageal cancer cells. Moreover the total activity of ADH as well as the activity of class IV ADH isoenzyme is significantly higher in cancer tissue than in healthy mucosa. The activity of these enzymes in cancer cells is reflected in the sera and could thus be helpful for diagnostics of esophageal cancer. The aim of this study was to investigate a potential significance of ADH isoenzymes and ALDH as tumour markers of esophageal cancer. We defined diagnostic sensitivity, specificity, predictive value for positive and negative results, and receiver-operating characteristics (ROC) curve for tested enzymes. Methods: Serum samples were taken for routine biochemical investigation from 180 patients with esophageal cancer before treatment. Total ADH activity was measured by a photometric method with p-nitrosodimethylaniline as a substrate and ALDH activity by a fluorometric method with 6-methoxy-2-naphtaldehyde as a substrate. For the measurement of the activity of class I and II isoenzymes we employed the fluorometric methods, with class-specific fluorogenic substrates. The activity of class III alcohol dehydrogenase was measured by a photometric method with formaldehyde and class IV with m-nitrobenzaldehyde as a substrate. Results: There was a significant increase in the activity of class IV of ADH isoenzyme (7.65 mU/l vs 5.88 mU/l) and total ADH activity (1198 mU/l vs 848 mU/l) in the sera of esophageal cancer patients compared to the control. The diagnostic sensitivity for ADH IV was 72%, the specificity 76%, the positive and negative predictive values were 80% and 72% respectively. The area under the ROC curve for ADH IV was 0.65. Conclusion: The results suggest a potential significance of ADH IV as a marker of esophageal cancer.
Electrophoretically specific nuclear proteins of human colon adenocarcinoma with mol. wt of 35-40 kDa were used as immunogen to produce rabbit antiserum. Expression of cancer-specific antigens was investigated by Western blot technique among nuclear proteins from normal and cancerous mucosa. Obtained antiserum crossreacted mainly with 36 kDa polypeptide in 23 of 26 (88,5%) colorectal tumor nuclear fractions but not with any of normal ones. It was also observed that this antiserum recognized 36 kDa antigen in 10 of 12 and 6 of 7 nuclear fractions from other cancers, ie. gastric and lung, respectively. In part of studied tumors antiserum crossreacted also with the antigens of 38 and 32-33 kDa. Expression of 36 and 32-33 kDa components seems to be correlated with colorectal cancer progression from A to B stage of disease according to the classification of Dukes. Immunoblot analysis revealed that cancer-specific 36 kDa polypeptide, mainly associated with nuclear compartment, can be also detected within 10P and 100P fractions of colorectal tumors.
The discovery of circulating nucleic acids in the 1940s opened up new possibilities for the non-invasive detection, monitoring and screening of various human disorders. Several tumour markers that enable early cancer detection or tumour behaviour prediction have been detected in the plasma of cancer patients. Maternal plasma analysis can be used to detect certain fetal abnormalities, with the quantification of cell-free nucleic acids used to screen for several pregnancy-associated disorders. Some other applications are in transplant monitoring and graft rejection assessment, and in certain medical emergencies such as trauma and burn severity stratification. Many studies have yielded promising results in this field, but the techniques have yet to be applied in routine clinical practice. Large-scale studies using similar technologies and a broad spectrum of patients are still needed to verify the results of the various studies.
Twenty-four male industrial workers, exposed to various chromium compounds for 1-17 years (but deprived of overt symptoms of chromium toxicity) were the subjects of our study. The workers’ urine chromium was measured serially by atomic absorption spectrometry. The simple kinetic model was proposed for tracking pre-shift and post-shift as well as day-to-day variation of urine chromium concentrations. This model proved to be useful in determining the biological effects of exposure to chromium compounds. Subsequently, the statistically significant associations of chromium status parameters (as delivered by the kinetic model) with biochemical indices, blood panel parameters, spirometric indices, and concentrations of tumour markers [carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag), cytokeratin 19 fragment (CYFRA 21-1), and neuron-specific enolase (NSE)] in those workers were evaluated by means of the hierarchical partial least squares method (PLS 2 model). These relations should be further studied in larger groups of workers. In several individuals, outlined in the PLS 2 model, cigarette smoking did not constitute any important source of chromium, although seniority at work in the chemical plant did influence biochemical status.
Carcinoembryonic antigen (CEA) is an oncofoetal cell surface glycoprotein that serves as an important tumour marker for colorectal and some other carcinomas. Its immunoglobulin-like structure places CEA within the immunoglobulin superfamily. CEA functions in several biological roles including homotypic and heterotypic (with other CEA family members) cell adhesion. Cell-cell interaction can be modulated by different factors, e.g., post-translational modifications such as glycosylation. The pur­pose of this study was to examine whether changes in carbohydrate composition of CEA oligosaccharides can influence homotypic (CEA-CEA) interactions. In order to modulate glycosylation of CEA we used two different glycosylation mutants of Chi­nese hamster ovary (CHO) cells, Lec2 and Lec8. Lec2 cells should produce CEA with nonsialylated N-glycans, while Lec8 cells should yield more truncated sugar struc­tures than Lec2. Parental CHO (Pro5) cells and the glycosylation deficient mutants were stably transfected with CEA cDNA. All three CEA glycoforms, tested in a solid-phase cell adhesion assay, showed an ability to mediate CEA-dependent cell ad­hesion, and no qualitative differences in the adhesion between the glycoforms were observed. Thus, it may be assumed that carbohydrates do not play a role in homotypic adhesion, and the interactions between CEA molecules depend solely on the poly- peptide structure.
Substrates for CYP2C9 include fluoxetine, phenytoin, warfarin, losartam and nu­merous nonsteroidal anti-inflammatory drugs. Polymorphisms in the coding region of the CYP2C9 gene produce variants at amino-acid residues 144 Arg/Cys and 359 Ile/Leu of the CYP2C9 protein. Individuals homozygous for Leu359 have markedly diminished metabolic capacities for most CYP2C9 substrates, the frequency of this al­lele is, however, rather low. Consistently with the modulation of enzyme activity by ge­netic and other factors, wide interindividual variability occurs in the elimination and/or dosage requirements of prototypic CYP2C9 substrates. The polymorphic en­zyme CYP2C9 takes part in the metabolism of alkylating agents and polycyclic aro­matic hydrocarbons like benzo(a)pyrene, a carcinogen present in tobacco smoke. Al­though the impact of impaired enzyme activity in metabolism of carcinogens and procarcinogens has not been fully defined, an association of CYP2C9 variant alleles to DNA adduct levels in lung tissues as well as to lung cancer risk have been reported. In this study 64 healthy subjects (44M/22F) were analysed for CYP2C9 genotype with PCR-RFLP and for serum carcinoembryonic antigen (CEA), α-fetoprotein (AFP), CA 19-9, CA 15-3, ferritin, IL-6, IL-8 concentrations by chemiluminescence or electro- chemiluminescence methods. CYP2C9*1 was found to be the most prevalent allele and CYP2C9*1/CYP2C9*1 was the most frequent genotype represented in 64% of the population in southeastern Anatolia (Gaziantep). Although slight differences in serum tumour marker and cytokine concentrations were observed for CYP2C9 genotypes the differences were statistically insignificant (P > 0.05). This could be due to the complexity of the role of CYP2C9 in benzo(a)pyrene metabo­lism as well as from other contributing factors like interindividual variability of di­verse enzymes participating in the same metabolic pathway, unequal expression of the variant alleles and differences in exposure to carcinogens. However, determination of CYP2C9 phenotypes in a larger group of subjects might clarify these slight differences.
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