Characterisation of glycoforms of ascitic fluids in benign and malignant diseases.

OBJECTIVES: To evaluate the differences in glycoforms of ascitic fluids which can be considered as useful in discrimination between benign and malignant patients. DESIGN AND METHODS: The investigations were carried out on 17 benign and 13 malignant patients. To obtain high molecular weight material, gel exclusion chromatography was applied. To evaluate the relative amounts of different glycoforms, ELISA tests with biotinylated lectins were used. RESULTS: The fucosylation pattern was found to be similar in malignant and benign group. Fucose linked by alpha 1-6 bond was the most abundant structure. Sialylation was found to be more typical for malignant patients. Alpha 2-6 bond was observed on higher level than alpha 2-3 linkage. T and Tn antigens were present on rather low level with a slight prevalence of T antigen in malignant group. The glycoforms recognized by DSA lectin were more numerous in benign patients. CONCLUSIONS: The evaluation of the level of some ascitic fluids glycoforms can be useful in differentiation between malignant and benign diseases.

The influence of Helicobacter pylori patients' treatment on MUC 1 content in gastric juice.

BACKGROUND/AIMS: Helicobacter pylori that resides in the gastric mucus layer is the major etiological factor in gastritis, gastric ulcers and carcinomas. Among others, carbohydrate structures of MUC 1 mucin are also considered by some authors as being important in the mechanism of infection. The main aim of our study was to establish whether Helicobacter pylori treatment has any influence on the level of soluble form of MUC 1 mucin in gastric juice. METHODOLOGY: We examined two groups of Helicobacter pylori infected patients. The first group was treated with omeprazole (at the end of the therapy the bacterium was still present). The second group was treated with omeprazole and antibiotics, and the bacterium eradication was confirmed. MUC 1 mucin was determined by Western blotting technique. RESULTS: Before the therapy, the level of MUC 1 was found to be low in almost all cases, while at the end of the treatment in both groups of patients an increase of MUC 1 mucin was observed. CONCLUSIONS: Our results can confirm the thesis that Helicobacter pylori inhibits the expression of MUC 1 mucin on cell membranes.

The effect of Helicobacter pylori eradication treatment on the MUC 1 and Lewis antigens level in human gastric juice: a preliminary study.

Helicobacter pylori is considered as a causative agent of gastritis, duodenal and gastric ulcers, and gastric cancer. During inflammation, association of the pathogen of gastric epithelial cells and mucins is considered important. It was postulated that Lewis b structures of secretory MUC 5AC mucin can be a receptor for the bacterium. Some authors also suggest that epithelial MUC 1 mucin may be implicated in the mechanism of infection. The main aim of our work was to support this last suggestion by evaluation of the possible changes in MUC 1 and Lewis a and b levels in gastric juice before and at the end of eradication treatment. The gastric juices of ten examined patients were chromatographed on a Sepharose 4 B column, electrotransferred on Immobilon P membranes, and assessed for MUC 1 and Lewis a and b structures using monoclonal antibodies. In 90% of examined patients, higher amounts of MUC 1 mucin were observed at the end of eradication treatment. Similar results for Lewis a and b structures were found. In the case of MUC 1 and Lewis b, the differences were statistically significant. Helicobacter pylori influences expression of the soluble form of MUC 1 mucin and Lewis a and b structures present in gastric juice.

[Molecular diagnosis of osteogenesis imperfecta type I]. / Diagnostyka molekularna wrodzonej lamliwosci kosci typu I.

UNLABELLED: Osteogenesis imperfecta (OI) is caused by mutations in collagen type I genes. In contrast to OI type II, III and IV where there are the structural mutations, in OI type I decreased production of normal collagen is due to the presence of a null allele. Because both pharmacological and gene therapy approaches depend on type of mutation and its consequences, quick and proper diagnosis is required. AIM OF THE STUDY: Application of COL1A1 null allele detection and analysis of collagen synthesized by skin fibroblasts in OI type I diagnosis. MATERIAL AND METHODS: Analysis was carried out in 17 patients and 20 healthy persons. Collagen was labeled with [3H]proline in skin fibroblasts and analyzed with electrophoretic method (SDS-PAGE) and by digestion with collagenase from Clostridium histolyticum. Nucleic acids were isolated from fibroblasts or peripheral blood and null allele was identified using a COL1A1 gene polymorphism. RESULTS: In the group of 17 OI patients 11 were heterozygous for insertion of 4 bp in 3'UTR region of COL1A1. "Null allele" was identified in 7 patients with decreased collagen synthesis by about 50% and in 2 patients with decreased collagen synthesis by 80% and 15%. However, in one patient with decreased collagen synthesis by about 50%, both allele transcripts were present. CONCLUSIONS: Application of 4 bp insertion in 3'UTR of COL1A1 gene to detect "null allele" confirmed clinical diagnosis in 9 among 17 OI patients. In 3 patients results of quantitative study of collagen and "null allele" detection were different, what indicate that for final diagnosis comprehensively studies are needed.

The changes in monosaccharide composition of immunoglobulin G in the course of rheumatoid arthritis.

The objective of this study was to determine whether galactosylation of immunoglobulin G (IgG) in patients with rheumatoid arthritis (RA) correlates with severity and duration of illness. Serum IgG glycosylation from 50 patients with RA in comparison with 30 healthy controls was analyzed. IgG from sera was isolated and monosaccharide composition was determined by means of gas chromatography. Ratio of galactose to mannose content was calculated. Patients were divided into groups according to three different criteria: disease duration, severity of RA (disease activity score index), and radiological degree of advancement of illness according to Steinbrocker. In patients with RA, significant decrease (p<0,01) of galactose ratio was observed in comparison with healthy control. In patients with long duration of RA (more than 15 years), significant decrease of galactose (p<0.05) ratio in comparison with patients who have had arthritis for less then 5 years was observed. For the group of patients with severe RA, we found reduction of galactose (p<0.001) ratio vs the group of patients in remission. For those patients who had radiological stage IV according to Steinbrocker, IgG galactose (p<0.01) content per oligosaccharide chain were also more decreased than in those patients who had stage I RA. Decreased galactosylation and of IgG in RA was observed. The lack of this carbohydrate component of IgG correlates with severity and duration of RA and could be used in monitoring the progression in early arthritis.

The influence of N- and O-glycosylation inhibitors on the glycosylation profile of cellular membrane proteins and adhesive properties of carcinoma cell lines.

The effects of N- and O-glycosylation inhibitors on the expression of membrane proteins (MUC1 and some integrins) were evaluated in human endometrial (Ishikawa) and breast (MCF-7) cancer cells. Subconfluent cells were treated with 1-3 mg% concentration of tunicamycin and 2-10 mM of benzyl-N-acetyl-alpha-galactosaminide for 1-2 days, and used for flow cytometry, immunohistochemical staining, adhesion test and Western blotting. Benzyl-N-acetyl-alpha-galactosaminide inhibits MUC1 expression on the surface of breast more than endometrial cancer cells. Tunicamycin reduces MUC1 concentration on the cellular surface more than benzylglycoside, and greatly reduces glycosylation of glycoproteins, causing an increase in cell adhesion in both types of cancer cells. The expression of alpha2beta1 integrins on the surface of these cells was weak and decreased after treatment with inhibitors. Two different glycoforms of MUC1 proteins in endometrial cells and three in breast cancer cells were expressed and their molecular weights were reduced after treatment with glycosylation inhibitors. It was confirmed with lectin detection of carbohydrate epitopes (Tn and T) in MUC1 proteins. These observations show that glycosylation inhibitors altered the N- and O-glycan patterns in a sufficient manner, and positively modified the biological features of cancer cells.

Phenotype variability in a daughter and father with mild osteogenesis imperfecta correlated with collagen and prolidase levels in cultured skin fibroblasts.

Studies of collagen biosynthesis and prolidase activity were performed on cultured skin fibroblasts obtained from a female patient and her father, who displayed variable phenotypes of mild osteogenesis imperfecta (OI). For comparison, the same studies were also performed on age-matched controls. Biosynthesis of collagen in fibroblasts of the less affected father was reduced to approximately 50% of control levels, whereas in cells of the more severely affected daughter, it was decreased to about 20% of control levels. Furthermore, the decrease in collagen synthesis in OI fibroblasts was accompanied by a parallel decrease in prolidase activity and expression of beta1 integrin and insulin-like growth factor-I (IGF-I) receptors recovered from the cells. Therefore, prolidase, as well as IGF-I and beta1 integrin receptors involved in collagen metabolism regulation, may represent important factors influencing OI phenotype.

Effect of cadmium on collagen content and solubility in rat bone.

The toxic action of cadmium in the bone tissue is known, but its mechanisms are still unexplained. We examined whether Cd influences collagen content and its solubility in the femoral bone of three-week-old female rats exposed to 5 or 50 mg Cd/l in drinking water. Non-cross linked collagen was extracted with 0.5 M acetic acid, and two acid-insoluble collagen fractions were extracted with pepsin and 4.0 M guanidine hydrochloride, respectively. SDS/PAGE showed the presence of two collagen types, I and V, in all three extracted fractions. Exposure of rats to Cd for 6 months increased the amount of acid-soluble collagens type I and V and decreased the level of acid-insoluble collagens. The amount of total collagen extracted from the bones of rats exposed to 50 mg Cd/l was reduced by about 14% as compared to control and those intoxicated with 5 mg Cd/l. The solubility of type I bone collagen (determined as the percentage of acetic-soluble fraction of total collagen) was increased 2.9- and 3.0-fold in rats intoxicated with 5 and 50 mg Cd/l, respectively. Similarly, the solubility of type V collagen was increased 2.3- and 2.7-fold, respectively. Our results indicate that Cd treatment affects bone collagen by decreasing its content and increasing its solubility.

Inhibition of the O-glycan elongation limits MUC1 incorporation to cell membrane of human endometrial carcinoma cells.

We have studied how benzyl-N-acetyl-alpha-D-galactosaminide, O-glycosylation inhibitor, affects the polymorphism and shedding of membrane-bound MUC1 mucin, and change in adhesive properties of cancer cells. In endometrial adenocarcinoma cells (Ishikawa line), high molecular weight MUC1 mucin was shed from cellular membrane and could be detected in culture medium 24 h after [14C]threonine labelling. Short-time (2 days) exposure of these cells to benzyl-N-acetyl-alpha-D-galactosaminide was associated with a reduction in sialic acid level and increase in T antigen content in cellular MUC1 mucin. These changes could be inverted after removal of the inhibitor. A longer, 6-day action of the inhibitor induced a decrease in sialic acid and T antigen levels in cellular MUC1 mucin. Benzyl-N-acetyl-alpha-D-galactosaminide treatment caused the occurrence of a few incompletely glycosylated glycoforms of MUC1 in cells, but not in culture medium. Adhesion of endometrial cells to ECM compounds (type I collagen) was increased by benzyl-N-acetyl-alpha-D-galactosaminide treatment, indicating that glycosylation of extracellular domain of MUC1 can modulate adhesive properties of cells.

Gly511 to Ser substitution in the COL1A1 gene in osteogenesis imperfecta type III patient with increased turnover of collagen.

Osteogenesis imperfecta (OI) is a result of heterozygous mutations in the COL1A1 or COL1A2 genes, encoding type I procollagen chains. Here we described the molecular and biochemical defects detected in a case of severe type III OI. Cultured skin fibroblasts from the proband produced both normal and mutant type I collagen which was secreted into the medium. The mutation site was localized in alpha 1(I)-CB3 by CNBr cleavage of collagen chains. Subsequent reverse transcription-PCR amplification and direct sequencing of single-stranded PCR product led to identification of G to A transition in the COL1A1 gene, resulting in Gly511Ser substitution in the a1 chain of type I collagen. The new mutation conforms to the chain-specific non-lethal microdomain of Gly to Ser substitutions in the genotype-phenotype map. We have found that biosynthesis of collagen was increased in OI cells to about 160% of the control value. However, the amount of collagen deposed to the insoluble matrix was decreased as compared to the control. This suggests increased degradation of collagen, since the collagenolytic activity of OI cells was increased. Furthermore, the activity of prolidase, which is a marker of collagen turnover, was increased in OI cells. In regulation of activity of the enzyme are involved beta1 integrin and insulin-like growth factor (IGF) receptors. Western immunoblot analysis showed that the expressions of both receptors were markedly increased in OI cells. These results suggest that increase in activity of prolidase can be associated with increase in intensity of collagen metabolism in type III OI patient with identified new G511S mutation.

Studies on type I collagen in skin fibroblasts cultured from twins with lethal osteogenesis imperfecta.

Studies on type I procollagen produced by skin fibroblasts cultured from twins with lethal type II of osteogenesis imperfecta (OI) showed that biosynthesis of collagen (measured by L-[5-(3)H]proline incorporation into proteins susceptible to the action of bacterial collagenase) was slightly increased as compared to the control healthy infant. SDS/PAGE showed that the fibroblasts synthesized and secreted only normal type I procollagen. Electrophoretic analysis of collagen chains and CNBr peptides showed the same pattern of electrophoretic migration as in the controls. The lack of posttranslational overmodification of the collagen molecule suggested a molecular defect near the amino terminus of the collagen helix. Digestion of OI type I collagen with trypsin at 30 degrees C for 5 min generated a shorter than normal alpha2 chain which melted at 36 degrees C. Direct sequencing of an asymmetric PCR product revealed a heterozygous single nucleotide change C-->G causing a substitution of histidine by aspartic acid in the alpha2 chain at position 92. Pericellular processing of type I procollagen by the twin's fibroblasts yielded a later appearance of the intermediate pC-alpha1(I) form as compared with control cells.

A novel Gly to Arg substitution at position 388 of the alpha1 chain of type I collagen in lethal form of osteogenesis imperfecta.

Cultured skin fibroblasts from a proband with a lethal form of osteogenesis imperfecta produce two forms of type I collagen chains, with normal and delayed electrophoretic migration; collagen of the proband's mother was normal. Peptide mapping experiments localized the structural defect in the proband to alpha1(I) CB8 peptide in which residues 123 to 402 are spaned. Direct sequencing of amplified cDNA covering this region revealed a G to A single base change in one allele of the alpha1(I) chain, that converted glycine 388 to arginine. Restriction enzyme digestion of the RT-PCR product was consistent with a heterozygous COL1A1 mutation. The novel mutation conforms to the linear gradient of clinical severity for the alpha1(I) chain and results in reduced thermal stability by 3 degrees C and intracellular retention of abnormal molecules.

Direct sequencing of PCR products for mutation detection in osteogenesis imperfecta.

This work present a short and simple method for mutation detection in type I collagen genes, based on the direct sequencing of single-stranded DNA. The sequencing of type I collagen genes is complicated and difficult because of their large size and highly repetitive and GC-rich coding regions. Although many techniques have been developed for mutation screening in osteogenesis imperfecta (OI), they represent different degrees of sensitivity and are difficult to reproduce and too expensive for application in each laboratory. The method described here is short, easy and especially useful for sequencing of collagen genes in OI cases, in which the region with a suspected structural defect is localized by collagen analysis.

Elongation factor 2 as a target for selective inhibition of protein synthesis in vitro by the novel aromatic bisamidine.

The effect of the novel aromatic bisamidine 1 on protein synthesis in cell-free translational system isolated from rat livers was studied. The bisamidine 1 caused inhibition of [14C]leucine incorporation into proteins proportionally to its concentration. To establish a precise mechanism of inhibition, we evaluated the effect of the bisamidine 1 on the isolated ribosomes and purified to homogeneity elongation factors. Preincubation of the bisamidine 1 with ribosomes resulted in partial inhibition of their activity in whole elongation system. The eucaryotic elongation factor 1 (eEF-1) was not significantly affected by the bisamidine 1. In contrast to eEF-1, the bisamidine 1 preincubated with the eucaryotic elongation factor 2 (eEF-2) caused total inhibition of its activity in the translocation process. The inhibitory effect of the bisamidine 1 on eEF-2 activity was confirmed in diphtheria toxin-dependent ADP-ribosylation reaction. The results suggest a high action specificity of the bisamidine 1 as potential anticancer drug, since the primary target seems to be highly conserved protein-elongation factor 2.

Comparative studies of osteoblast and fibroblast type I collagen in a patient with osteogenesis imperfecta type IV.

The expression of type I collagen has been compared in fibroblast and osteoblast cultures of a patient with moderately severe osteogenesis imperfecta (OI) type IV, with respect to control cells. Electrophoretic analysis of type I collagen showed that both OI osteoblasts and fibroblasts synthesized normal chains and chains with delayed migration. However, the osteoblasts contained a higher proportion of abnormal chains than fibroblasts from the proband. Pulse-chase experiments showed that the trimers containing abnormal chains were cleared more rapidly from osteoblasts than fibroblasts. Moreover, the collagen secreted by OI osteoblasts had thermal stability 1 degrees C higher than collagen secreted by OI fibroblasts. These results suggest that the abnormal collagen in osteoblasts may be more resistant to intra- and extracellular degradation and may thus have better survival than in fibroblasts. This finding could have implications for understanding the clinical phenotype of OI.