Lectin binding in normal, keratoconus and cross-linked human corneas.

In this study the characterization of various types of sugar residues in normal, keratoconus and cross-linked human corneas was performed using immunohistochemical localization with lectins. Corneal samples were collected and divided into three groups: (1) normal corneas from cadavers; (2) keratoconic corneal buttons; (3) keratoconic corneal buttons treated with cross-linking. A series of lectins including: DBA, SBA, PNA, ConA, WGA, UEA I, GNA, DSA, MAA, SNA, were used in combination with chemical and enzymatic treatments. Compared with the normal corneas, N-acetyl-D-glucosamine increased in the keratoconus corneas. L-fucose increased and/or appeared in the keratoconus and the cross-linked corneas. N-acetyl-D-galactosamine was more abundant in the epithelium of keratoconus corneas, but was lacking in the keratoconus and cross-linked endothelium. D-galactose-(ß1-4)-N-acetyl-D-glucosamine was absent in the whole stroma of the keratoconus corneas and in the deep layers of the cross-linked ones. Sialic acids increased in the keratoconus corneas and decreased in the cross-linked ones. These results showed altered glycosylation in the keratoconic corneas and partially similar glycosylation in the cross-linked corneas, compared to the normal ones. This suggests a role played by sugar residues in maintaining the corneal structure. The changes could be related to structural alterations in keratoconus. The present findings contribute to our understanding of the effect of cross-linking treatment of keratoconic corneas in therapeutic attempts to re-establish the normal corneal structure.

The sialoglycoconjugates in the oviducts of fertile and postmenopausal women.

OBJECTIVES: The aim of the study was to investigate the distribution of the sialoderivatives of the glycoconjugates in the oviduct of normally menstruating and postmenopausal women. METHODS: Biopsies of ampullary and isthmic portions of the oviduct were obtained from fertile women, in proliferative and secretive phases, and from postmenopausal subjects. The study was carried out using digoxigenin-labelled lectins (MAA, SNA and PNA) in addition to the use of enzymatic and chemical treatments to characterize the different glycosidic linkages of the sialoderivatives and to obtain information on their structure. RESULTS: No appreciable difference in sialoderivatives distribution was observed among the oviducts, particularly at the epithelium luminal surface, of the fertile women in the two menstrual cycle phases or among those of the fertile and some postmenopausal women, independently from age. Moreover, no appreciable difference of distribution was observed between the ampullary and the isthmic portions in both the study groups. CONCLUSIONS: In the fertile women sialoderivatives present at the luminal surface of the epithelial cells could play a role in sperm capacitation and mobility, and facilitate the transit of the egg and of the early embryo along the oviducts. The similar distribution of sialoderivatives in the oviduct epithelium of some postmenopausal women of different age, compared to the fertile ones, suggests a maintaining of some functions of the organ, independently from the age of the woman. This could be due, in some cases, to the influence of remaining still sufficient sex hormonal levels.

Distribution of the glycoconjugate oligosaccharides in the human placenta from pregnancies complicated by altered glycemia: lectin histochemistry.

The aim of this study was to investigate the distribution of the oligosaccharides of the glycoconjugates in placentas from pregnancies complicated by different degree of altered glycaemia. Placentas from women with physiological pregnancies (group 1), with pregnancies complicated by minor degree of glucose intolerance (group 2) and with pregnancies complicated by gestational diabetes mellitus (GDM) treated with insulin (group 3) were collected. Ten lectins were used (ConA, WGA, PNA, SBA, DBA, LTA, UEA I, GSL II, MAL II and SNA) in combination with chemical and enzymatic treatments. The data showed a decrease of sialic acid linked alpha(2-6) to galactose/N-acetyl-D-galactosamine and an increase of N-acetyl-D-glucosamine in the placentas of the pathological groups, in particular the group 3, comparing to the group 1. A decrease of L-fucose (LTA) and D-galactose-(beta1-3)-N-acetyl-D-galactosamine, and an increase and/or appearance of L-fucose (UEA I) and N-acetyl-D-galactosamine were observed in both the pathological groups, particularly in the group 2, with respect to the group 1. In GDM, and even in pregnancies with a simple alteration of maternal glycaemia, the changes in the distribution of oligosaccharides could be related to alteration of the structure and functionality of the placenta.

Lectin binding in the umbilical cord in altered glycemia.

OBJECTIVE: Content and distribution of the oligosaccharides in the umbilical cord from pregnancies with altered glycemia were investigated. STUDY DESIGN: A prospective cohort study was conducted in the Florence Policlinic of Careggi, Italy. Samples of cord from physiological pregnancies (n=20), from pregnancies with minor degree of glucose intolerance (n=20) and from pregnancies with gestational diabetes mellitus (GDM) treated with insulin (n=20) were collected. Eleven lectins were used (ConA, WGA, PNA, SBA, DBA, LTA, UEA I, OOA, GSL II, MAL II and SNA) in combination with chemical and enzymatic treatments. RESULTS: Increase of N-acetyl-d-glucosamine and a loss of sialic acid in the umbilical cord of the cases with minor degree of glucose intolerance with respect to the other study groups was observed. d-Galactose(beta1-->3)-N-acetyl-d-galactosamine, N-acetyl-d-galactosamine and l-fucose were in less amount in both the pathological groups with respect to the control one. CONCLUSION: The increase of some glycoconjugates carbohydrates and the loss of others in the umbilical cord from pregnancies with minor degree of glucose intolerance might be related to its morphofunctional alterations in a not diabetic altered glycemia. Moreover, the treatment with insulin in the GDM might play a role in restoring partially the normal glycosilation in the cord components in the attempt to renew some their functions.

Lectin binding in the ependymal cells of the cephalic portion of the nervous system in the chick embryo.

The content, distribution and changes of the glycoconjugates oligosaccharides in the ependymal cells of the cephalic portion of the nervous system, in the chick embryo from 5 days of incubation till hatching and in the 3 days old chicken, were investigated. For this purpose a battery of six HRP-conjugated lectins were used (WGA, SBA, UEA I, LTA, PNA, ConA). Enzyme and chemical treatments were performed on some sections prior to staining with HRP-lectins. Our findings showed a large amount of all the investigated sugar residues at the apical portion of the ependymal cells, for the whole considered period of incubation and in the 3 days old chicken. This could indicate that also the immature ependymal cells (spongiobasts) begin to play a tipical role of the mature cells. The presence of cytoplasmic sopranuclear granules, containing D-glucosamine, D-galactose-(beta --> 3)-N-acetil-D-galactosamine and sialic acid in the early stages of incubation, might represent a secretion by the ependymal cells to integrate a not yet fully functioning secretion by the choroid plexuses. At the ciglia a large amount of oligosaccharides were detected in the second part of the period of incubation and in 3 days old chicken. These oligosaccharides could be involved in determining and mantaining the movement of the ciglia to facilitate the flow of the CSF.

The oligosaccharidic content of the glycoconjugates of the prepubertal descended and undescended testis: lectin histochemical study.

The saccharidic content of the glycoconjugates has been studied in the descended the undescended testes of a 8 years old boy. For this purpose, a battery of seven HRP-conjugated lectins (SBA, DBA,PNA,WGA,UEAI, LTA and ConA) was used. D-galactose-N-acetyl-D-galactosamine and alpha-L-fucose sugar residues, which were present in the cytoplasm of the Sertoli cells of the normally positioned prepubertal testis, were not detected in the same cells of the undescended testis. The Leydig's cells of the descended testis appeared characterized by N-acetyl-D-glucosamine which was absent in the rare and atrophic Leydig's cells of the cryptorchid testis. Differences in sugar residues distribution between the descended and the undescended testis were also detected in the lamina propria of the seminiferous tubules. Peritubular myoid cells in the undescended testis only reacted with PNA, after neuraminidase digestion, thus revealing the presence of D-galactose (beta1-->3)-N-acetyl-D-galactosamine and sialic acid. In this study a complete distributional map of the sugar residues of the glycoconjugates in the descended and undescended prepubertal testis is reported.

Lectin-binding sites in newborn human testis.

The present investigation has been performed to obtain a complete distributional map of the oligosaccharidic component of the glycoconjugates in the testis of the human newborn. For this purpose seven eight HRP-conjugated lectins (SBA, DBA, PNA, WGA, OOA, UEAI, LTA and ConA) along with enzymatic treatments, were used. The Sertoli cells were characterized by the same sugar residues detected in the testes of adult healthy subject. Beta-N-acetyl-D-galactosamine in the Leydig's cells and a-N- acetyl-D-galactosamine anomer in the spermatogonia seem to be an unique feature of the newborn testis. For this fact SBA and DBA could be considered markers respectively of the Leydig's cells and of the spermatogonia in the newborn testis. Differences in lectin binding, between the newborn and the adult testis as the interstitial tissue and the endothelial cells of the capillary vessels are reported.

VEGF expression in the placenta from pregnancies complicated by hypertensive disorders.

OBJECTIVE: To determine the expression of VEGF in the placental tissue from pregnancies complicated by hypertension disorders of different clinical severity. DESIGN: Prospective cohort study. SETTING: Polyclinic of Careggi, University of Florence, Italy. SAMPLE: Placentas from women with gestational hypertension (n= 20), pre-eclampsia (n= 20) and pre-eclampsia with HELLP syndrome (n= 20) and from normotensive women (n= 20), as control group (gestational age comprised between 35 and 38 weeks). METHODS: An immunohistochemical technique and a quantitative analysis to measure mRNA levels (RT-PCR) were employed. MAIN OUTCOME MEASURES: Intensity of immunoreactivity and mRNA levels in the placental components. Differences between the data. RESULTS: VEGF immunoreactivity was observable in all the placental components in the gestational hypertension cases as in the control ones. In the cases with pre-eclampsia and pre-eclampsia with HELLP syndrome, some placental components were not immunoreactive. However, the VEGF positive components of all the pathological groups showed a higher intensity of reactivity with respect to that of the control group. The levels of VEGF mRNA were higher in the gestational hypertension cases and lower in the cases of pre-eclampsia with HELLP syndrome with respect to the control ones; in the cases of pre-eclampsia, the levels were the same as the control ones. CONCLUSION: The different expression of VEGF in the placenta of the pathological cases is probably related to haemodynamic changes that take place in these disorders, in order to attempt restoration of a normal uteroplacental flow.

Lectin binding in the choroid plexuses of the chick embryo.

In the present research we have studied the distribution and the changes of the oligosaccharidic component of the glycoconjugates during the development of the choroids plexuses of the 3rd ventricle and of the lateral ventricles in chick embryos and in 3-day-old chicken. For this purpose a battery of seven horseradish peroxidase labelled lectins was used. Lectin histochemistry has shown that starting from early stages of choroid plexuses development, all its components, epithelial cells, mesenchyme and endothelial cells of the capillary vessels, show lectin reactivity. In the present paper the possible role played by the sugar residues of the glycoconjugates in the apical portion and in the cytoplasm of the choroid epithelial cells and in the basement membrane is discussed.

Effects of 0.2 T static magnetic field on human skin fibroblasts.

Human skin fibroblasts were exposed to 0.2 T static magnetic field generated by a magnetic resonance tomograph. After 1h exposure, cell morphology was modified in association with a concomitant decrease in the expression of some sugar residues of glycoconjugates. Study of cell proliferation and mitogenic signal transduction showed a decrease of thymidine incorporation and of second messenger formation. However, cell viability, assessed by colony forming assay, was unaffected. These results demonstrate that the static magnetic field generated by routinely used magnetic resonance tomograph induces alterations on human skin fibroblasts.

Morphologic changes in the microcirculation induced by chronic smoking habit: a videocapillaroscopic study on the human labial mucosa.

BACKGROUND: Cigarette smoking has been identified as a major risk factor for cardiovascular and pulmonary diseases. Although an impressive literature does exist on the subject, no evidence is available on morphologic changes induced with chronic smoking habit in the human microcirculation. SUBJECTS AND METHODS: One hundred healthy subjects, 50 smokers and 50 nonsmokers, underwent videocapillaroscopy of the labial mucosa. For each subject, the caliber of capillary loops, the number of visible capillary loops, the background optical transmittance, the tortuousness of capillary loops, the presence of microaneurysms, the presence of microhemorrhages, and the cumulative smoking habit (pack-year index) were noted. RESULTS: Smokers had a lower caliber of capillary loops (P <.001), with a higher number of visible capillary loops (P <.001), a lower background optical transmittance (P <.001), and a more marked tortuousness of capillary loops (P <.001). Microaneurysms and microhemorrhages were absent in nonsmokers, and 1 smoker of 3 had microaneurysms alone, and 1 smoker of 3 had both microaneurysms and microhemorrhages. A significant correlation was found between cumulative smoking habit and tortuousness of capillary loops (P <.001) and between cumulative smoking habit and total score (tortuousness score + microaneurysm score + microhemorrhage score; P <.005). CONCLUSION: Chronic smoking habit does induce significant morphologic changes in the microcirculation of the human labial mucosa, and these changes can be easily and comfortably recorded with videocapillaroscopy.

Use of Horseradish Peroxidase Conjugated Lectins for Detection of Glycoconjugate Changes in Developing Lingual Epithelium of the Chick Embryo: (lectins//glycoconjugates/epithelium/tongue/chick embryo).

A battery of six different horseradish peroxidase-labelled lectins (SBA, DBA, PNA, WGA, ConA and LTA) was used to study the distribution of carbohydrate residues in glycoconjugates during the development of the chick embryo tongue anlage (7th-21st day of incubation) and in the tongue of 3 day-old chicken, at the dorsal and ventral epithelium. From the 7th to the 16th day ß-D-galactose, D-galactose-(ß1 → 3)-N-acetyl-D-galactosamine, D-mannose and ß-N-acetyl-D-glucosamine show the same epithelial distribution at two lingual aspects. From the 17th day to hatching the epithelium of the dorsal and ventral surfaces is characterized by a different distribution of sugar residues. The functional adaptation of the epithelium, as far as the saccharidic moletie distribution is concerned, seems to be completed at the 21st day of incubation.