Serum sCD26 for colorectal cancer screening in family-risk individuals: comparison with faecal immunochemical test.

BACKGROUND: The development of specific screening programs for individuals with a family history of colorectal cancer (CRC) is a priority. This study evaluates the diagnostic performance of serum soluble CD26 (sCD26) in family-risk individuals and compares this marker with the faecal immunochemical test for the detection of advanced neoplasia (AN) (CRC or advanced adenomas; AA). METHODS: Five hundred and sixteen asymptomatic individuals with at least one first-degree relative with CRC were included. Serum sCD26 was measured in all the individuals who also underwent a colonoscopy (53 AA and four cancer cases were found) and a faecal immunochemical test. RESULTS: Setting specificity to 90% and 95%, respectively, sCD26 showed a sensitivity of 39.6% and 28.3% for AA, and of 42.1% and 28.1% for AN. The combination of sCD26 and the faecal test detected AA and AN with a 52.8% and 56.1% sensitivity, corresponding to 93.5% specificity. CONCLUSIONS: The combination of serum sCD26 and the faecal blood test could result a valuable strategy for detecting AN in familial-risk CRC screening.

Ultrastructure and glycoconjugate pattern of the foot epithelium of the abalone Haliotis tuberculata (Linnaeus, 1758) (Gastropoda, Haliotidae).

The foot epithelium of the gastropod Haliotis tuberculata is studied by light and electron microscopy in order to contribute to the understanding of the anatomy and functional morphology of the mollusks integument. Study of the external surface by scanning electron microscopy reveals that the side foot epithelium is characterized by a microvillus border with a very scant presence of small ciliary tufts, but the sole foot epithelium bears a dense field of long cilia. Ultrastructural examination by transmission electron microscopy of the side epithelial cells shows deeply pigmented cells with high electron-dense granular content which are not observed in the epithelial sole cells. Along the pedal epithelium, seven types of secretory cells are present; furthermore, two types of subepithelial glands are located just in the sole foot. The presence and composition of glycoconjugates in the secretory cells and subepithelial glands are analyzed by conventional and lectin histochemistry. Subepithelial glands contain mainly N-glycoproteins rich in fucose and mannose whereas secretory cells present mostly acidic sulphated glycoconjugates such as glycosaminoglycans and mucins, which are rich in galactose, N-acetyl-galactosamine, and N-acetyl-glucosamine. No sialic acid is present in the foot epithelium.

Secreted clusterin in colon tumor cell models and its potential as diagnostic marker for colorectal cancer.

We studied the specific changes of the secreted protein clusterin and its cytoplasmic precursor regarding colorectal tumorigenesis, using in vitro differentiation of Caco-2 cells. In tumor-like stage, we observed an overexpression of both precursor and secreted clusterin, corroborated in the cell line SW-480. Noticeably, SW-620 cells (from a tumoral node, thus with metastatic capacity) did not show overexpression of either precursor or secreted clusterin, suggesting a downregulation related to local metastasis. We further investigated clusterin in serum, finding a significant increase in colorectal cancer patients, with 81% sensitivity, 79% specificity, and an area under the ROC curve of 0.85.

Clinical significance of preoperative serum sialic acid levels in colorectal cancer: utility in the detection of patients at high risk of tumor recurrence.

This study was conducted to evaluate the significance of preoperative serum sialic acid levels in the diagnosis and prognosis of colorectal cancer (CRC). Total sialic acid (TSA) was determined by the thiobarbituric acid method and normalized to total protein (TP). A postoperative follow-up of CRC patients classified as Dukes' stages A, B or C was performed and survival analysis was carried out to evaluate the impact of sialic acid levels on tumor recurrence. Our diagnostic studies indicate that TSA/TP is a better marker than either TSA or carcinoembryonic antigen (CEA), especially for the detection of CRC patients at an early stage. At a cutoff of 30.90 nmol/mg of protein, TSA/TP showed a sensitivity of 85% with a specificity of 97% to discriminate CRC patients from healthy donors. In survival analysis, both TSA and TSA/TP were found to be significant prognostic factors for tumor recurrence in CRC. Furthermore, TSA/TP could distinguish patients at high risk of recurrence within Dukes' stage B and in multivariate analysis it was identified as the best independent prognostic factor. According to our results, preoperative serum TSA/TP content could supply additional information to that provided by Dukes' stage about the prognosis of CRC patients.

Cell surface human alpha-L-fucosidase.

The acid alpha-L-fucosidase is usually found as a soluble component of lysosomes where fucoglycoconjugates are degraded. In the present investigation, we have demonstrated the existence of a cell surface protein with enzymatic alpha-L-fucosidase activity that crossreacts specifically with a rabbit anti-(alpha-L-fucosidase) Ig. By different approaches, this alpha-L-fucosidase, which represents 10-20% of the total cellular fucosidase activity, was detected in all the tested human cells (hemopoietic, epithelial, mesenchymal). Two bands of approximately 43-49 kDa were observed, although theoretical data support the possibility of having the same genetic origin that the known 50 to 55-kDa Mr alpha-L-fucosidase. We speculate about an alternative traffic pathway for the plasma membrane alpha-L-fucosidase to work on the rapid turnover of glycoproteins.

Value of the serum alpha-L-fucosidase activity in the diagnosis of colorectal cancer.

OBJECTIVES: The purpose of this study was to assess the value of the serum levels of alpha-L-fucosidase activity in the diagnosis of patients with colorectal cancer. METHODS: Using a fluorometric method we analyzed the alpha-L-fucosidase activity in preoperative sera from 137 colorectal cancer patients and in sera from 232 donors. RESULTS: The enzymatic activity of alpha-L-fucosidase was significantly lower (p <0.001) in patients (4.8+/-3.09 U/ml) than in donors (10.5+/-5.46 U/ml). Using the ROC curve, the ideal cut-off for the diagnostic value of alpha-L-fucosidase activity was determined to be 5.6 U/ml. The diagnostic efficiency for colorectal cancer of alpha-L-fucosidase activity was higher than that observed for carcinoembryonic antigen (cut-off 5.0 ng/ml), especially for tumors at an early stage. CONCLUSIONS: Our results suggest that preoperative serum alpha-L-fucosidase activity may be used as a cheap and easy complementary test, in addition to standard clinical procedures routinely used for the diagnosis of colorectal cancer.

Alpha-L-fucosidase enzyme in the prediction of colorectal cancer patients at high risk of tumor recurrence.

The aim of this study was to examine the prognostic value of the alpha-L-fucosidase enzyme to determine whether it can help in the early recognition of colorectal cancer cases at high risk of tumor recurrence. One hundred and twenty-three colorectal carcinoma patients treated by curative surgery were studied. The alpha-L-fucosidase activity was assayed in the tumor and in normal mucosa from each patient using a fluorometric method. Seven other clinical and pathologic features were also studied. To evaluate the impact of each variable over the disease-free interval, a postoperative 30-month follow-up of patients was performed, and a statistical survival analysis was carried out. The recurrence appearance was higher when the relative decrease of alpha-L-fucosidase activity was more than 52% (log-rank test, P = .0261). The results of this work indicate that alpha-L-fucosidase activity appears to be a good independent prognostic factor of tumoral recurrence in colorectal carcinoma.

Immunohistochemical analysis of sialic acid and fucose composition in human colorectal adenocarcinoma.

The expression of different sialoglycoconjugates and fucoglycoconjugates in normal mucosa and adenocarcinoma samples from 43 colorectal cancer patients was investigated by using specific lectins and applying a semiquantitative analysis. A pronounced decrease in the intracellular binding of the Maackia amurensis lectin, which recognizes alpha(2,3)-linked sialic acid residues, was found in the tumoral tissue. In contrast, a significant increase in the staining with the Sambucus nigra lectin (SNA I), which binds to alpha(2,6)-linked sialic acid residues, was detected in the epithelial cells as well as in the mucins from tumors. No significant differences in the reactivity with the Aleuria aurantia lectin, which recognizes the sequence Fuc(alpha1,6)GlcNAc, between normal and malignant colorectal tissues were detected. Furthermore, the correlation between lectin-binding profiles and the prognosis of colorectal cancer patients was examined. After an average postoperative follow-up period of 31 months, patients with tumors showing a strong SNA I staining presented a greater probability of disease recurrence. This result suggests that the intensity of staining with SNA I could be a valid parameter for predicting recurrence in colorectal cancer.

Sialic acid levels in serum and tissue from colorectal cancer patients.

Sialic acid levels were determined in serum and in both normal and tumour-derived tissues from 30 patients with colorectal cancer. Total sialic acid (TSA), bound sialic acid (BSA),TSA normalised to total protein (TSA/TP) and BSA normalised to total protein (BSA/TP) were significantly higher (P < 0.0001) in sera from patients than in normal subjects. We found a trend of increasing serum sialic acid levels (TSA/TP and BSA/TP) as the malignancy became more severe (i.e. Dukes' stages A to C). Comparison of sialic acid levels between normal and tumour-derived colorectal tissues indicated no statistically significant differences in TSA, BSA or FSA (free sialic acid) levels between both tissues; however, TSA/TP and BSA/TP values were significantly decreased (P < 0.05) in the tumoral tissue. In this study, the possible relation between serum and tumour sialic acid levels in colorectal cancer patients was investigated. Our results showed that in these patients there was no correlation between serum BSA and tumour BSA levels.

Fucose levels in sera and in tumours of colorectal adenocarcinoma patients.

Fucose levels were determined in normal and tumour-derived tissues from patients with colorectal adenocarcinoma. Total, free and bound fucose were significantly higher (P < 0.001) in the tumoral tissue. Comparison of serum fucose levels between patients with colorectal cancer and control subjects indicated no statistically significant differences in total, free and bound fucose expressed as nmol/ml serum. However, when total and bound fucose were normalized to total protein (nmol/mg protein), an elevation in both parameters was found in colorectal cancer patients, although only that for total fucose was statistically significant (P < 0.001). A clear association between fucose content and clinical stage of patients according to the Dukes' classification can not be established, although patients at stage C showed higher levels of fucose both in serum and tissue. The current investigation provides direct evidence of a relationship between the elevation of fucose and the presence of tumour in colorectal cancer patients.

Ganglioside content of rat liver after administration of ethanol and pentazocine or sucrose supplemented diets.

In a previous paper, we determined the effect of either ethanol or pentazocine administered separately on the ganglioside content of rat liver. In the present paper we have investigated the effect of pentazocine injection on the liver ganglioside contents of chronic alcoholic rats. The effect of high carbohydrate ingestion was also studied. Thirty male Wistar rats were divided into three experimental groups that received ethanol and pentazocine, a carbohydrate supplemented diet or a laboratory diet and water. Liver ganglioside contents were slightly increased in the ethanol plus pentazocine group as compared to the control and high carbohydrate diet groups. No differences were found between the two latter groups. The percentage distribution of individual gangliosides (ganglioside pattern) was also modified. A decrease in gangliosides belonging to the b-series (GD3, GD1b, GT1b and GQ1b) in parallel with an increase in that of the a-series (GM2, GM1 and GD1a) were found for both the ethanol plus pentazocine and the high-carbohydrate fed rats. The results suggest that ethanol or high carbohydrate ingestion diminishes the activity of GD3 synthase, a key enzyme in the metabolism of gangliosides, which determines the proportion of gangliosides, belonging to the a- and b-series.

Human colon sialidase: characterization and activity levels in normal mucosa and colonic adenocarcinoma.

Human colon sialidase has been characterized, and its activity levels in normal mucosa and colonic adenocarcinoma have been determined. Sialidase activity was maximal at pH 5.5, and was unstable with storage at 4 and -20 degrees C. The bulk of activity was pellet-associated, and could not be released with triton X-100 or 3-([3-cholamidopropyl]- dimethylammonio)-1-propanesulfonate. Using 2'-(4-methylumbelliferyl)alpha-D-N-acetylneuraminic acid as substrate, the Km and Vmax values were estimated to be 0.140 mmol/l and 63 mU/g, respectively. Furthermore, an inhibition by substrate concentrations above 1.5 mmol/l was detected. Neuraminic acid caused a competitive inhibition with a Ki of 3.5 mmol/l. A statistically significant increase (p < 0.001) in the sialidase specific activity was found in primary colonic adenocarcinoma (104.20 +/- 8.00 mU/g) compared to that of the normal mucosa (72.50 +/- 7.67 mU/g).

Ganglioside and phospholipid composition of forebrain, cerebellum, and brain stem from adult and newborn rats.

The aim of this study was to elucidate whether sex or pregnancy state might affect the content and/or pattern of gangliosides from the forebrain, cerebellum and brain stem of rats. Adult male, mother (1-day after offspring) and nonpregnant rats of similar age were analyzed. Non-significant differences in ganglioside concentrations and patterns were found for the respective neural area of adult male and female rats except for a decrease in cerebellum and brain stem content from mothers and 12.0 months-old males, respectively. Thus, it seems that neither sex nor pregnancy hormones affect these parameters. By contrast, significant differences were found for pattern and ganglioside contents between adult (male and female) rats and newborns (1 day-old). Newborns showed a significant decrease in their forebrain (2.5-fold), cerebellum (2.0-fold) and brain stem (2.0-fold) ganglioside content when compared with adult (male and female) rats. Significant increases (p less than 0.001) were found in the phospholipid and cholesterol contents in the different brain areas in mothers versus their newborns. The phospholipid pattern also showed significant changes in all brain areas, with an increase (p less than 0.001) in phosphatidylethanolamine percentage in adult animals, among the main variations. An explanation for these facts is suggested.

Comparative studies of two acid beta-galactosidases from rabbit and bovine kidney.

Comparative studies of two acid beta-galactosidases from rabbit and bovine kidney have been made. The enzyme from rabbit (enzyme I) was purified 450-fold, and the activity of the bovine enzyme (enzyme II) was enriched 250-fold using conventional purification methods. Both purified enzymes were characterized and their properties were compared. Enzyme I showed a lower optimal temperature and was less pH stable. Enzyme II appeared to be homogeneous in charge, in contrast to the heterogeneity observed for enzyme I. Studies on their specificity using natural substrates showed that enzyme I hydrolyzed GM1, asialofetuin and lactose. However, enzyme II was only able to cleave galactose from the disaccharide. Some of the carbohydrates tested acted as activators for enzyme II, suggesting a mechanism of transglycosilation. Using lactose as substrate we confirmed the ability of enzyme II to transfer galactose residues to D-maltose and N-acetylgalactosamine.