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S J Kimber

Publications and source records attributed to S J Kimber.

At least 37 records · Page 2Linked to original sources
PubMed1994

Changes in alpha (1-2)-fucosyltransferase activity in the murine endometrial epithelium during the estrous cycle, early pregnancy, and after ovariectomy and hormone replacement.

alpha (1-2)-Fucosyltransferase (alpha (1-2)-FT) activity in the uterine luminal epithelium was investigated during the estrous cycle, during early pregnancy, and in ovariectomized mice treated with ovarian steroids. Phenyl-beta-D-galactoside was used as a specific acceptor for alpha (1-2)-FT activity. Enzyme activity fell dramatically throughout the pre- and peri-implantation period (Days 1-6 of pregnancy). Activity on Day 4 of pregnancy represented less than a tenth of the Day 1 level and by Day 6 became undetectable. During the estrous cycle alpha (1-2)-FT showed a peak of activity at estrus, the level being similar to that observed on Day 1 of pregnancy. In proestrus, postestrus, and diestrus, activity was similar and was approximately one fifth of that during estrus. Ovariectomized mice were primed with estrogen and treated with progesterone only, estradiol benzoate only, or progesterone followed by a single injection of progesterone and estradiol. Estrogen alone stimulated alpha (1-2)-FT activity, while progesterone treatment was strongly inhibitory. These results correlate well with the pattern of expression of the fucosylated H-type-1 carbohydrate epitope found on the endometrial epithelium and believed to have a role in implantation. alpha (1-2)-FT is capable of catalyzing the final step in formation of the H-type-1 oligosaccharide, and on the basis of our results it is likely that control of this enzyme is the major factor responsible for modulating H-type-1 expression.

Adenosine Triphosphate↗
PubMed1994

Sialylation of terminal saccharides of glycoconjugates expressed by murine molar tooth germs developing in vitro and in vivo.

During development of the mammalian tooth germ the pattern of terminal saccharides of glycoconjugates changes, with many structures losing lectin reactivity in a consistent pattern. This study investigated whether the epitopes are lost or become masked by terminal sialylation, using a combination of neuraminidase treatment of sections and sialic acid-reactive lectins. The results suggested that most of the terminal galactosamine and fucose sites in the epithelial enamel organ were removed during morphogenesis. Conversely, during condensation of the dental mesenchyme, masked peanut agglutinin (PNA)-reactive galactose epitopes appeared. During differentiation and organisation of the mesenchyme into odontoblasts and a subodontoblastic layer the PNA-reactive sites became masked again. These regions also specifically expressed sialylated glucosamine. However, at the proliferating epithelial cervical loop galactose sites appeared to be masked. This was more pronounced during in vitro development when abnormal expression of PNA-reactive sites was found at the cervical loop. Additionally, fucosylated sites persisted in the enamel organ, further indicating that the expression of terminal saccharides was disrupted during development in the organ culture system. These data suggest that loss of terminal galactose and galactosamine is related to differentiation of the cells. However, whether this loss occurs by removal or sialic acid masking is not dependent either on the origin of the cells or the epitope being lost.

Animals↗
PubMed1994

Expression of N-CAM in fertilized pre- and periimplantation and parthenogenetically activated mouse embryos.

The expression of the cell adhesion molecule of the immunoglobulin family, neural cell adhesion molecule (N-CAM), in the pre- and periimplantation embryo was examined by immunocytochemistry. N-CAM is expressed on unfertilized ovulated oocytes, fertilized preimplantation embryos at all stages of development and parthenogenetically activated eggs and embryos. In fertilized embryos, expression from the 4-cell stage can be partially inhibited by blocking embryonic transcription before 38 h post human chorionic gonadotropin (hCG). Expression of N-CAM was reduced on the trophoblast of day 6 blastocysts in culture, weak on the trophoblast of embryonic outgrowths and disappears from invading trophoblast in utero. An antibody against alpha(2-8) linked polysialic acid, mAb2-2B, reacted with embryos from the 8-cell stage, and staining was similarly reduced on the trophoblast of blastocysts at the time of implantation. These results suggest a role for N-CAM in the interactions of cells of the preimplantation mammalian embryo which requires further investigation.

Amanitins↗
PubMed1993

Carbohydrate antigen expression in murine embryonic stem cells and embryos. I. Lacto and neo-lacto determinants.

A comparative study of lacto- and neo-lacto series carbohydrate antigens between the undifferentiated and differentiated derivatives of the embryonic stem (ES) cell line E14 and expression in the early embryo is reported. Antibodies to neo-lacto and lacto (type 1 and 2) precursor chains and blood group antigens such as H (types 1 and 2) A, B and Lewis (Le-a, Le-b, Le-x, Le-y) were examined. Backbone lacto- and neo-lacto structures were present on undifferentiated cells, as were terminal alpha-gal, SSEA-1, Le-y and low levels of Le-a. On differentiation, Le-x (SSEA-1 determinant) disappeared as has been found for embryonal carcinoma (EC) cells, and other determinants became restricted to cells of particular morphology. These observations will aid determination of the status and phenotypic stability of long-term embryonic stem-cell cultures.

Animals↗
PubMed1993

Carbohydrate antigen expression in murine embryonic stem cells and embryos. II. Sialylated antigens and glycolipid analysis.

A mouse embryonic stem (ES) cell line E14 and early mouse embryos were stained with a panel of 15 monoclonal antibodies recognizing sialylated or potentially sialylated carbohydrate determinants. Sialyl Le-x and sialyl Le-a were detected on the pre-implantation embryo from the 8-cell stage, and sialyl Le-a weakly on undifferentiated ES cells. Changes in cell surface carbohydrates occurred after induction of ES cell differentiation with retinoic acid (RA) and dibutyryl cAMP. Qualitative analysis of the neutral glycolipids of untreated and RA-treated ES cells using high-performance thin-layer chromatography (HPTLC) revealed few differences between the two types of culture. The major gangliosides in both cultures were indicative of an active 'a' ganglioside synthesis pathway. GD3, a precursor of the 'b' synthesis pathway, previously reported to be characteristic of embryonal carcinoma (EC) cells, was absent. RA-induced differentiation caused a shift in the spectrum to more complex gangliosides. Application of fast atom bombardment mass spectrometry (FAB-MS) to permethylated derivatives of individual bands permitted partial characterization of an unusual sialylated glycolipid and a rare ganglioside with the suggested structure of GalNAc-GD1a.

Animals↗
PubMed1992

Effect of slow and ultra-rapid freezing on cell surface antigens of 8-cell mouse embryos.

The distribution of four cell surface antigens (SSEA-1, SSEA-3, SSEA-4, and I) present on mouse preimplantation embryos was examined on 8-cell stage embryos immediately after flushing from the reproductive tract and after slow or ultra-rapid freezing. Frozen-thawed and nonfrozen embryos were also examined after culture in vitro for 5, 24, or 48 h. Immediately after thawing, embryos showed a disruption in the polarity of cell surface antigens SSEA-3, SSEA-4, and I, but no differences were detected in fluorescence intensity or various other staining characteristics. No long-term changes in the distribution of cell surface components were detected. Implantation and embryonic development were similar for frozen and nonfrozen embryos transferred to the uterine horns of pseudopregnant recipients.

Animals↗
PubMed1992

Immunofluorescent lectin binding patterns and glycoprotein co-localization in the developing murine molar tooth.

Fluorescein-conjugated lectins were used in conjunction with antibodies to laminin, tenascin and amelogenin to investigate saccharide expression in the developing tooth germ. At the bud stage, peanut agglutinin (PNA) binding demonstrated residues that may be D-galactose-(beta 1----3)DGalNAc, and this staining occurred after the expression of tenascin. Only the cap-stage enamel organ suprabasal cells and the enamel knot stained intensely with Ulex europeus agglutinin-I, but not Lotus tetragonolobus agglutinin, implying the transient presence of blood group H type I oligosaccharides. At the late stages of amelogenesis, enamel synthesis is preceded by en bloc loss of inner enamel basement membrane components. Before this, Bandeiraea (Griffonia) simplicifolia--I (BSL-I) staining was lost from postmitotic ameloblasts, suggesting that a glycosylated species is initially removed. Additionally, PNA was co-localized with amelogenin protein, suggesting that it may express beta-D-galactosyl sequences. These results indicate that the glycosylation patterns of matrix components during odontogenesis may be important as they vary in a manner similar to that of the well-known glycoproteins.

Acetylgalactosamine↗
PubMed1990

Monoclonal antibody 43-9F as a sensitive immunohistochemical marker of carcinoma in situ of human testis.

Invasive germ cell cancer can be prevented if the neoplasia is diagnosed at the stage of carcinoma in situ (CIS). In routine histologic examination CIS may be overlooked, particularly in prepubertal individuals. The detection of this early malignancy may be greatly facilitated by use of immunohistochemical staining. The authors investigated the sensitivity of an immunohistochemical staining procedure with monoclonal antibody 43-9F in detection of CIS. Testicular specimens from 19 adult and two prepubertal individuals with CIS were tested. Positive staining reaction on the surface of malignant germ cells was encountered in all 21 specimens with CIS. The epithelial cells of the excretory ducts between testis and epididymis, including rete testis and canaliculi efferentes, reacted also positively with 43-9F. No staining was observed in nonmalignant testicular cells including Sertoli cells or Leydig cells in any of these samples or in testicular biopsy specimens from 27 adult and 11 prepubertal subjects without evidence of testicular neoplasia. Monoclonal antibody 43-9F was also found to react with cells of all four tested invasive testicular germ cell tumors. Thus, the monoclonal antibody 43-9F is a sensitive immunohistochemical marker of CIS germ cells and may also be of potential value in detection of invasive testicular cancer.

Adult↗
PubMed1990

Hormonal control of a carbohydrate epitope involved in implantation in mice.

Ovariectomy and hormone replacement of mice were used to examine the hormonal control of expression on the uterine surface of a carbohydrate determinant (lacto-N-fucopentaose I, LNF I), involved in the initial interaction between the blastocyst and the endometrial epithelium at implantation. Pseudopregnant mice mated with sterile males were also used to elucidate the impact of embryonic signals on the expression of this antigen on the uterine surface. Two groups of fucosylated structures could be distinguished; one group was predominantly dependent on maternal oestrogen and progesterone, while the other group appeared to be less influenced by the hormonal milieu.

Animals↗
PubMed1988

Distribution of some Gal beta 1-3(4)GlcNAc related carbohydrate antigens on the mouse uterine epithelium in relation to the peri-implantational period.

Using monoclonal antibodies of defined carbohydrate specificity we have looked at the distribution of various Gal beta 1-3(4)GlcNAc related oligosaccharide determinants in the mouse uterus during the first 6 days of pregnancy. Frozen sections of uterus from B6D2F1, B6CBF1 or B6D2F1/BOM female mice were incubated with the monoclonal antibodies and then with a fluorescein isothiocyanate conjugate of goat anti-mouse IgM and viewed by epifluorescence illumination. None of the antibodies bound specifically to stroma cells but antibodies recognising difucosylated Gal beta 1-3(4)GlcNAc structures, the monofucosylated type II determinant (SSEA-1) and an H type I oligosaccharide bound to cells of the uterine luminal epithelium and glands and to the uterine secretions. Antibodies recognising the three different types of saccharide showed independent changes in staining intensity during early pregnancy. The antibody which recognises H type I structures (667/9E9) showed a change in distribution from binding to most cells of the uterine epithelium in the non-pregnant mouse and on day 3 of pregnancy to binding restricted to areas of epithelial cells interspersed with non-staining clumps of cells between days 4 and 5 of pregnancy.

Animals↗
PubMed1988

The milk oligosaccharide, lacto-N-fucopentaose I, inhibits attachment of mouse blastocysts on endometrial monolayers.

Seven oligosaccharides isolated from human milk were tested for their effect in an in-vitro model of mouse blastocyst adhesion and trophoblast outgrowth on endometrial epithelial monolayers. One compound, lacto-N-fucopentaose I (LNF I), produced a significant reduction in the percentage of attached and outgrown blastocysts after co-culture for 72 h (P less than 0.001). No significant effect of any other tested oligosaccharide was obtained.

Animals↗
PubMed1987

Fucosylated glycoconjugates in mouse preimplantation embryos.

Preimplantation mouse embryos were metabolically labelled with 3H or 14C-fucose to investigate the synthesis of fucosylated macromolecules. Scintillation counting revealed that there was a progressive increase in both total fucose taken up by the embryo and incorporation of fucose into TCA-precipitable material as embryos developed from the 4-cell to the blastocyst stage. This was reflected in the increasing intensity of bands on autoradiographs of radioactive fucose labelled proteins separated on 10% SDS-PAGs between the 4-cell embryo (at which stage bands were first detectable) and the blastocyst. Minor qualitative changes in fucoproteins were detected at the time of compaction and additional bands appeared at the blastocyst stage. Preliminary analysis of fucolipids in 6- to 8-cell embryos indicated that an approximately equal amount of fucose was incorporated into lipid and protein. Autoradiographs of semi-thin sections of 3H-fucose-labelled embryos showed substantial amounts of radioactive material in the vicinity of the plasma membrane both adjacent to other cells and facing the zona pellucida. These data would support a predominant role for fucoconjugates in cell surface events in the preimplantation embryo from the 8-cell stage.

Animals↗
PubMed1986

Distribution of lectin receptors in postimplantation mouse embryos at 6-8 days gestation.

We have examined the pattern of binding of eleven lectins--BSL-II, WGA, LPA, Con A, DBA, SBA, LTA, UEA-I, MPA, PNA, and RCA-I, with specificity for a range of saccharides, to postimplantation mouse embryos from 6 to 8 days of gestation. The lectins were used to stain sections of ethanol-fixed paraffin-embedded and formaldehyde-fixed gelatin-embedded embryonic material. Our observations reveal a complex pattern of lectin binding to both cell surfaces and cytoplasm. Many of the lectins bind particularly to the outer surface of visceral endoderm (e.g., DBA, WGA, SBA, and RCA-I) and to the surface of the proamniotic cavity (e.g., RCA-I, PNA, and WGA). In the newly formed mesenchyme of primitive-streak-stage embryos, galactose and N-Ac-neuraminic acid are present but lectins with specificity for other sugars either did not bind to the cells or bound only in small amounts.

Animals↗
PubMed1986

The relationship between emerging neural crest cells and basement membranes in the trunk of the mouse embryo: a TEM and immunocytochemical study.

The earliest stage of neural crest cell (NCC) migration is characterized by an epitheliomesenchymal transformation, as the cells leave the neural tube. There is evidence that in a number of cell systems this transformation is accompanied by alteration or depletion of associated basement membranes. This study examines the ultrastructural relationship between mouse NCCs and adjacent basement membranes during the earliest stages of migration from the neural tube. Basement membranes were identified by transmission electron microscopy (TEM) and immunofluorescence using antibodies to type-IV collagen. The ultrastructural features of NCCs and their relationship with surrounding tissues were also examined using TEM. In the dorsal region of the neural tube, from which NCCs originate, the basement membrane was depleted or absent, and with the immunofluorescence technique it was shown that this pattern was reflected in a deficit of type-IV collagen. TEM observations indicated that ultrastructurally NCCs differ from their neuroepithelial neighbours only in overall cell shape and their relationship to other cells and the extracellular matrix.

Animals↗
PubMed1986

Distribution of fibronectin, laminin and entactin in the environment of migrating neural crest cells in early mouse embryos.

The distribution of the extracellular matrix molecules fibronectin, laminin and entactin was studied in frozen sections of 9 1/2-day mouse embryos in order to relate their presence to neural crest cell migration. It was found that all three components were present in basement membranes, laminin and entactin being mainly restricted to these. Fibronectin was present at high levels in basement membranes and extracellular spaces throughout the embryo, including the regions of neural crest cell migration. Fibronectin is known to affect migration in a variety of cell systems, so its presence in the embryo at the time of migration may indicate that it is influencing cell movement. This influence is likely to be via the cell surface through interactions with other matrix components such as glycosaminoglycans, and possibly entactin and laminin.

Animals↗