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PubMedDate not supplied

[Glycoconjugates of the cecal intestinal epithelium of the chick before and after hatching: histochemical study performed with peroxidase-conjugated lectins].

A battery of seven different horseradish peroxidase-labelled lectins (PNA, ConA, DBA, SBA, LTA, WGA and UEA I) was used to study the distribution and changes of carbohydrate moieties of glycoconjugates in the caecal epithelium (proximal and distal tracts) of the chick embryo and of the 3 days old chicken. The chief results showed that: 1. The appearance of some sugar residues was earlier observed at the epithelium of the distal tract than the proximal one (Tab. 2). 2. The presence of sialic acid was detected only after hatching (Fig. 4, Tab. 2). 3. During the embryonic caecal development enterocytes and goblet cells were characterized by the presence of the same sugar residues (Tab. 2). 4. By a quantitative point of view, differences in sugar residues content between the epithelium of the proximal and distal tract were observed. The epithelial cells of the distal tract were generally characterized by an higher content of saccharide moieties (Tab. 2). 5. At the end of the incubation period and after hatching enterocytes and goblet cells showed differences in content of some sugar residues (Fig. 1-3, Fig. 5-8, Tab. 2).

Animals↗

PubMed1991

Glycoconjugates in colon mucosa during the development of human fetuses.

The changes in the composition of glycoconjugates in the colon of human embrya and fetuses were studied using the methods of lectin histochemistry. Glycosylation was estimated in various sections of the colon during the development with special attention to intracellular localization. The changes were compared with the process of glycosylation in the tumor-transformed mucosa of the colon. The application of the obtained data to medical practice is discussed.

Carbohydrate Sequence↗

PubMed1990

Anticoagulant activity with dose-related response of glycoconjugates from bovine sublingual gland.

In this study we extracted glycoconjugates from bovine sublingual gland and attempted to investigate anticoagulant properties on blood coagulation of humans. To this purpose we performed the thromboelastographic technique and selective hemocoagulation screening tests. In particular, findings from screening tests indicated the occurrence of hemostatic effects on thrombin time (TT) and activated partial thromboplastin time (aPTT) with a response in a dose-related manner, whereas significant changes were not found on prothrombin time (PT).

Animals↗

PubMedDate not supplied

[Distribution of saccharide residues in glycoconjugates of the kidney in Gallus domesticus using peroxidase-conjugated lectins].

A battery of seven different horseradish-peroxidase labelled lectins (DBA, PNA, SBA, UEA I, WGA, ConA, LTA) was used to study the distribution of sugar residues in the glycoconjugates along the nephron and the collecting duct of the kidney of Gallus domesticus. As far as the glomerular components are concerned, we have demonstrated that the podocytes and, with a lesser extent, the mesangial cells are characterised by the presence of D-mannose, D-galactose-(beta 1- greater than 3)-N-acetyl-D-galactosamine and sialic acid. The glomerular capillary wall shows the presence of the disaccharide D-galactose-(beta 1- greater than 3)-N-acetyl-D-galactosamine and sialic acid. With regards to the tubules, the proximal tubule, the descending limb of the loop of Henle, the connecting tubule and the collecting one, are characterised by N-acetyl-D-galactosamine, (1- greater than 6)-alpha-L-fucose, D-mannose, N-acetyl-D-galactosamine and D-galactose-(beta 1- greater than 3)-N-acetyl-D-glucosamine. The cells of the connecting and collecting ducts show the presence of intracellular sialic acid, found also as component of the mucous secretion. The ascending limb of the loop of Henle and the distal tubule contain only three saccharidic residues, i.e. (1- greater than 6)-alpha-L-fucose, D-mannose and N-acetyl-D-glucosamine. Lectin histochemistry was also useful to define the saccharidic components of the mucus, which is normally present within the connecting and collecting ducts of the kidney of the birds. The cellular variability of the connecting and the collecting ducts is similar to that found in the kidney of some mammals. Such a variability seems to suggest a possible cell specialization along a single kidney tubule.

Animals↗

PubMed1990

[Conformation analysis of carbohydrate chains of glycoconjugates].

A problem of conformations of carbohydrate chains of glycoconjugates-glycoproteins and glycolipids--is reviewed. Experimental data (NMR, X-Ray) and theoretical conformational analysis data are discussed. Spatial structures of O-linked oligosaccharides from blood-group glycoproteins, N-linked oligosaccharides of different types (oligomannosidic, complex, hybrid, bisect) and carbohydrate chains of glycosphingolipids are considered.

Carbohydrate Conformation↗

PubMedDate not supplied

Comparative evaluation of enzyme immunoassays based on synthetic glycoconjugates and phenolic glycolipid-I for immunodiagnosis of leprosy.

Enzyme immunoassays (EIAs) based on synthetic glycoconjugates containing the terminal monosaccharide (M-BGG) or disaccharide (ND-BSA) residue of the trisaccharide component of phenolic glycolipid-I (PGL-I), for immunodiagnosis of leprosy are described. The results of the assays were compared with that of the EIA using PGL-I. All the three assays were highly specific for leprosy. The per cent positivity of active lepromatous leprosy (LL) patients with M-BGG was 78.05 in comparison to 85.36 with ND-BSA and 82.11 with PGL-I. Similarly, the positivity of tuberculoid (TT) leprosy patients in M-BGG assay was lower than that in EIAs using ND-BSA or PGL-I. However, the difference in the positivity of individual category of leprosy patients in the three EIAs was not statistically significant. The correlation between absorbance values of leprosy sera in EIAs based on M-BGG and PGL-I, as well as that in assays using ND-BSA and PGL-I was statistically significant.

Antigens, Bacterial↗

PubMed1990

6-[18F]fluoro-L-fucose: a possible tracer for assessing glycoconjugate synthesis in tumors with positron emission tomography.

The potential of 6-[18F]fluoro-L-fucose (6-[18F]FFuc) for assessing glycoconjugate synthesis in tumors with positron emission tomography (PET) was investigated. Using the tissue sampling method with five tumor models, different time-radioactivity profiles were found: a nearly constant level in Lewis lung carcinoma (3LL) and different clearance patterns in others. Rapid clearance in normal tissues resulted in preferable uptake ratios for tumor imaging of brain and pancreas. Metabolic studies and the L-fucose loading effects on the tissue uptake proved the tracer to be a biochemically active L-fucose analog. Imaging of the intracranial rat glioma and 3LL in lungs or hepatomas in mice by autoradiography (ARG) and intramuscular VX-2 carcinoma in rabbits by PET was demonstrated. Using double-radionuclide ARG, similar distribution images of 6-[18F]FFuc and 14C-L-fucose but different tumor-to-liver uptake ratios were found. A metastasis model seemed to show a higher uptake of both tracers as compared to a primary tumor model.

Animals↗

PubMed1990

Glycoconjugate expression in normal hepatoid glands and hepatoid gland adenomas and carcinomas in dogs.

Although neoplastic changes in canine hepatoid perianal glands (HPG) are quite common, the biological behaviour is sometimes difficult to assess on the basis of the histopathological examination. In an attempt to detect differences in the glycoconjugate expression between normal and neoplastic HPG, and to verify their relation to the degree of neoplastic progression, normal and neoplastic HPG were studied in 13 dogs, using 11 biotinylated lectins. In HPG adenomas the majority of the cells did not stain or stained weakly after incubation with pokeweed mitogen, LCA and UEA-I. In HPG carcinoma the basal cells lost the specific binding for WGA while heterogeneous distribution of conconavalin-A staining was observed.

Adenoma↗

PubMed1989

Activation of phospholipase D by the fucose-sulfate glycoconjugate that induces an acrosome reaction in spermatozoa.

We report for the first time that phospholipase D activity in sea urchin spermatozoa can be regulated by a component of egg jelly known to induce an acrosome reaction. The fucose-sulfate glycoconjugate (FSG) of egg jelly that induces an acrosome reaction in spermatozoa caused Ca2+-dependent increases in 1,2-diacylglycerol and phosphatidic acid. Diacylglycerol concentrations were increased 2-fold, and phosphatidic acid concentrations were elevated up to 10-fold 2 min after the addition of FSG to spermatozoa. FSG also caused increases in choline, but not in choline phosphate concentrations. Neither phosphorylation of diacylglycerol nor de novo synthesis from glycerol were significant routes of synthesis of phosphatidic acid during the acrosome reaction. When spermatozoa were incubated with FSG in the presence of ethanol, phosphatidylethanol was produced. As ethanol concentrations in the extracellular medium were increased from 0.1 to 2.5%, the amount of phosphatidylethanol increased, whereas phosphatidic acid concentrations decreased, suggesting a competitive transphosphatidylation reaction catalyzed by phospholipase D. Furthermore, when a phosphatidylcholine pool in spermatozoa was radiolabeled using [3H]1-O-alkyl-2-lyso-glycerol-3-phosphorylcholine, the subsequent addition of FSG caused a 4-fold accumulation of [3H]phosphatidic acid. FSG-induced elevations in [3H]phosphatidic acid were positively correlated with the percent of cells that had undergone an acrosome reaction.

Acrosome↗

PubMed1988

Seroepidemiological studies of leprosy in northern Malawi based on an enzyme-linked immunosorbent assay using synthetic glycoconjugate antigen.

A total of 6002 blood samples from total population samples in four separate areas within Karonga District, Northern Malawi, were tested for anti-Mycobacterium leprae antibody using an ELISA based on synthetic glycoconjugate antigen. Results are presented using different criteria for seropositivity. Regardless of the criterion used, the proportion of individuals classified as "positive" rose to a peak at 20-30 years of age and then fell, and it was higher at all ages in females than in males. There was no difference in seropositivity levels between individuals with or without BCG scars. Although leprosy cases, in particular those with positive smears, had higher antibody levels than nonleprosy cases, analysis of age-standardized data revealed only weak evidence for a correlation between the prevalence rates of clinical leprosy and of seropositivity within the four areas. There was no evidence for higher seropositivity levels in household contacts of leprosy cases compared to noncontacts. The implications of these results for the epidemiology of leprosy in this population are discussed.

Age Factors↗

PubMed1988

Detection and differentiation of glycoconjugates in various cell types by lectin histochemistry.

Knowledge of chemical structure of glycoconjugates (GCs) at precise loci has increased through histochemical use of a battery of horseradish peroxidase-conjugated lectins, each possessing affinity for a specific terminal sugar or internal sugar linkage. Lectin histochemistry has shown tremendous variability among GCs in different histologic sites, reflecting known chemical diversity of these substances. GCs differ in structure among various cell types in an animal and differ at a given histologic site between species or between individuals in outbred but not inbred species. Lectin conjugates react with and detect GCs not otherwise demonstrable histochemically and, because of low concentration in tissue, not identified biochemically. Lectin-HRP conjugates have visualized unique GC with terminal GalNAc in primordial germ cells of rat embryos, with terminal Gal in epithelial basal cells of rodents and nodes of Ranvier in rats and with terminal GalNAc in a cell population in the thymus, Peyer's patches and intestinal lamina propria of some but not other mice.

Animals↗

PubMed1988

[Localization of glycoconjugates in tissues of mammals revealed by means of labeled lectins].

Histochemical peculiarities on binding of castor-oil plant, soybean and lentil lectins with tissues of the mucous membrane in the stomach, small and large intestine have been studied in the human being, rat, mouse, as well as the lectins mentioned and the maize agglutinin with the nervous tissue of the rat cerebral tissue. The reactions are carried out with nonfixed cryostat and deparaffinized histological slices. Lectins labelled with horseradish peroxidase are used. Certain specific peculiarities and differences concerning the lectin binding with tissues of the organs studied are determined. Predominant binding is noted of the soybean lectin with parietal and mucin-producing cells of the stomach, with epitheliocytes of the duodenal glands, with the brush border of the epithelial cells of the intestinal villi. The lentil and castor-oil plant lectins make contours of the basal membrane epithelium in the stomach and intestine. The lentil lectin also reacts with the germinative centers of the stomach lymphatic nodules and the castor-oil plant agglutinin--with the brush border of the small intestine epitheliocytes. The lectins used are predominantly bound with neurons of the subcortical formations of the rat brain and cerebral cortex. By means of labelled lectins of lentil, soybean, and castor-oil plant it is possible to reveal certain modifications of the rat small intestine glycoconjugates produced by means of the immortelle extract.

Animals↗

PubMed1988

Effect of fluororotic acid on the sialylation of the chicken liver, hepatoma MC-29 and serum glycoconjugates.

Fluororotic acid, an orotic acid analogue which interferes with the nucleotide and RNA biosynthesis, was tested to determine its effect on: a) 14C-glucosamine and 14C-N-acetylmannosamine incorporation into acid-soluble nucleotide-sugars and into b) glycoconjugates from chicken liver and hepatoma induced by the avian leukosis strain Mc-29. In vivo metabolism studies indicated that this agent alters the nucleotide biosynthesis in both tissues investigated and causes a decrease in the sialylation rate of liver, hepatoma and serum glycolipids and glycoproteins.

Animals↗

PubMed1988

Detection of mucus glycoconjugates in human cervical epithelium by lectin-colloidal gold technique in transmission electron microscopy. I. A quantitative study during the menstrual cycle.

We investigated the presence and distribution of five glycosidic residues at the level of the endocervical columnar epithelial cells during the various phases of the menstrual cycle in healthy subjects. We utilized the lectins Wheat Germ Agglutinin (WGA), Peanut Agglutinin (PNA), Soybean Agglutinin (SBA), Concanavalin A (ConA) conjugated with colloidal gold particles as ultrastructural markers in Transmission Electron Microscopy. This technique proved to be particularly suitable for detecting glycosidic residues at the cellular level, where the mucus is produced. All the lectin-binding sites (except ConA binding sites which were not detected) appeared to be produced in significantly different amount during the cycle, supporting the hypothesis that the cyclic-related changes of the cervical mucus viscoelasticity is due to glycoconjugate cyclic variations.

Acetylgalactosamine↗

PubMed1995

Substance P stimulates the loss of cell-associated high molecular weight glycoconjugates from cultured hamster tracheal epithelial cells through polymorphonuclear leucocytes activation.

Abnormal and excessive mucus secretion is a characteristic feature of many chronic inflammatory lung diseases accompanied by the influx of polymorphonuclear leucocytes (PMNs) into the airway and the release of substance P from the peripheral endings of primary sensory neurons. We examined whether PMNs activated by substance P (10 microM) can affect the secretion of high-molecular-weight glycoconjugates (HMWG), which is used as a marker of mucus, from cultured hamster tracheal epithelial cells. We measured both the released and the cell-associated HMWG. Substance P-activated PMNs (10(6) cells/ml) reduced the amount of cell-associated HMWG to 76% of the control level, but did not affect the amount of the released HMWG. The reduction of the amount of cell-associated HMWG was inhibited by ONO-5046, a specific elastase inhibitor. In addition, the HMWG was digested by the activated PMNs. These findings suggested that substance P stimulates the loss of the cell-associated HMWG and degrades the released HMWG from cultured hamster tracheal epithelial cells through PMNs activation.

Animals↗

PubMed1995

Glycoconjugate expression of chondrocytes and perichondrium during hyaline cartilage development in the rat.

Alterations in the expression of glycoconjugate structures during cartilage development in the chondrocranium, nasal skeleton, Meckel's cartilage, limb buds, vertebral bodies and ribs were investigated comparatively in 13 to 21-d-old rat embryos. The binding patterns of 24 biotinylated lectins were analysed in serial sections and compared with results obtained using histochemical methods. Proteoglycan distribution, assessed by conventional staining procedures, was not associated with lectin binding sites. During early fetal development, hyaluronate concentrations were enhanced in areas of prospective chondrogenesis. With few exceptions, the lectins showed a general increase in intensity of binding to mesenchymal structures. Con A (Canavalia ensiformis), DSL (Datura stramonium), and WGA (Triticum vulgare) displayed a ubiquitous distribution of binding sites. After incubation with LCA (Lens culinaris), PSA (Pisum sativum), STL (Solanum tuberosum), and VAA (Viscum album), characteristic differences in binding intensity between focal areas of developing mesenchyme were seen. DBA (Dolichus biflorus), ECL (Erythrina cristagalli), GSL I (Griffonia simplicifolia), LTA (Lotus tetragonobolus), SJA (Saphora japonica), UEA I (Ulex europaeus) and VVL (Vicia villosa) consistently failed to bind. During chondrogenesis a general reduction of lectin staining was detected. In early stages of development GSL II (Griffonia simplicifolia) was a specific marker of the prechondral blastema in the viscerocranium. PNA (Arachis hypogaea) selectively labelled the prevertebral blastema. In contrast, condensing mesenchyme of limb buds and viscerocranium was not stained. Using RCA (Ricinus communis), it was possible to distinguish chondroblasts from mature cells. All chondrocytes were stained by PSA, PHA-E, PHA-L (Phaseolus vulgaris E and L), and WGA, whereas Con A, LCA, and GSL II detected distinct differences between cartilage with different localisations. Cartilage matrix was constantly negative. Applying GSL II it was possible to distinguish specific segments of the perichondrium. From our results we conclude that especially high mannose oligosaccharides are amplified during development. Terminal sialic acid molecules, branched intralaminar glucose and/or mannose, respectively, internal galactose-(beta 1,4)-N-acetylglucosamine sequences as well as galactose-(beta 1,3)-N-acetylgalactosamine sequences in a preterminal position are diffusely distributed in mesenchymal tissue. In contrast, no evidence for the presence of terminal GlcNAc(beta 1,4)GlcNAc sequences and terminal alpha-fucosyl residues in (1,2) or (1,3)-linkage was obtained. Chondrogenesis appears to be correlated with a general reduction in the extent of expression of oligosaccharide structures. No proof of terminal N-acetylgalactosamine and alpha-galactose moieties was found, whereas our staining results document the expression of terminal beta-galactose structures in restricted areas of the developing mesenchyme.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylglucosamine↗

PubMed1994

Androgen status and expression of glycoconjugates and lectins in the epithelial cells of the mouse ventral prostate. A glycohistochemical approach.

We investigated histochemically the expression of glycans and endogenous sugar-binding proteins (endolectins) in the ventral prostate of normal and androgen-deprived mice. The avidin-biotin-peroxidase complex technique was used with a panel of biotinylated lectins and neoglycoproteins, respectively, on paraffin sections. Characteristic binding patterns depending upon the type of lectin were observed in the glandular epithelium and basement membranes. This report also initiates the histochemical study of endogenous glycan-binding proteins in this male-accessory sex organ. Remarkably, the endocrine status was found to affect the distribution of lectin-reactive determinants of glycoconjugates as well as endolectins. The histophysiological significance of these modifications in the glandular cells are discussed in the light of previous biochemical findings obtained mainly in humans and the rat.

Androgens↗

PubMed1994

[Electron microscopic histochemical study in human trabecular meshwork--Second report: location of glycoconjugate residues using lectins].

The location of fourteen lectins in normal human trabecular meshworks were investigated with the electron microscope. The specimens were embedded in Lowicryl K4M at low temperature. Ultrathin sections were stained with biotin labeled lectins and colloidal gold labeled streptoavidin and observed with the electron microscope. ABA, ConA, DSA, PHA-E1, PHA-L4, WGA, LCA, and RCA120 were localized around fine fibrils underneath the endothelium of the trabecular wall of the Schlemm's canal (type I plaque) and collagenous fibers in the corneoscleral meshworks. ABA, ConA, and DSA were localized on the long-spacing collagens, basal membrane, microfibrils of elastic fiber (type II plaque), and fine granular (type III plaque). The present study indicated that extracellular matrices of normal human trabecular meshworks contained specific glycoconjugate residues.

Aged↗