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Biomedical subjects

J D Aplin

Publications and source records attributed to J D Aplin.

At least 73 records · Page 4Linked to original sources
PubMed1993

Patterns of sialylation in differentiating rat decidual cells as revealed by lectin histochemistry.

Lectin histochemistry was used to demonstrate changes in the surface glycan distribution of uterine stromal cells as they differentiate to form decidual cells. Decidualization was induced in hormone-treated, ovariectomized rat uteri by needle scratch. Uterine tissue from days 2 to 8 of deciduoma development was examined with a panel of lectins specific for terminal non-reducing structures in N- and O-linked classes of glycoprotein glycan, including alpha 2,3- and alpha 2,6-linked sialic acid residues. Immunostaining for desmin was used to identify decidual cells. An increase in N-linked glycans associated with the cell surface and recognized by lectins from Phaseolus vulgaris (leukoagglutinin) (l-PHA), Pisum sativum (PSA) and Triticum vulgaris (WGA) was found during the early growth of decidual cells. As decidualization progressed regionally from the antimesometrial to mesometrial uterus, an increase in alpha 2,3-linked sialic acid residues was followed by a loss of the alpha 2,6-linked form. The results suggest that as stromal cells differentiate, glycoprotein biosynthesis and glycosyl transferase activity are altered. These changes in patterns of glycosylation may give rise to altered decidual cell-matrix and cell-cell interactions during differentiation and play a role in the modulation of decidual cell interactions with trophoblast during early placentation.

Animals↗
PubMed1992

Endometrium in in-vitro fertilization cycles: morphological and functional differentiation in the implantation phase.

Secretory differentiation of endometrium after multiple follicular stimulation using gonadotrophin releasing hormone and human menopausal gonadotrophin has been studied both histologically and immunohistochemically in 30 women undergoing in-vitro fertilization treatment. None had embryo transfer. Patients were randomly allocated to receive luteal phase support with a single dose of human chorionic gonadotrophin. The latter failed to produce any significant enhancement of endometrial structure or secretions. Appropriate glandular morphology was present in a greater proportion of those who were successfully stimulated than those who responded poorly. However, defective secretion of the cycle-dependent component studied, using monoclonal antibody D9B1, was demonstrated in two-thirds of cases regardless of the ovarian response. Early vascular maturation in the stroma was a common finding, and was thus considered as a feature of structural modulation of these endometria.

Antibodies, Monoclonal↗
PubMed1992

Loss of collagen type VI from rat endometrial stroma during decidualization.

The expression of collagen type VI in the extracellular matrix of rat uterine endometrial stroma after a decidual stimulus was examined by immunolocalization and immunoblotting. The intermediate filament protein, desmin, was used as a marker to identify decidual cells. Tissue was examined from pregnant animals and from ovariectomized, hormone-treated rats in which decidualization had been induced artificially. In undifferentiated tissue from both groups of animals, collagen type VI was abundant, and desmin was present only in vascular smooth muscle cells. By 72 h after a decidual stimulus, however, collagen type VI had essentially disappeared from the matrix of the antimesometrial stromal compartment, and desmin was highly expressed in the decidualizing cells. During regression of the decidual tissue, collagen type VI began to reappear in the stromal matrix, whereas desmin expression declined as decidual cells degenerated. These results indicate that remodeling of the uterine extracellular matrix in response to embryo implantation is a function of the differentiating decidual cell.

Animals↗
PubMed1992

The distribution of alpha 6 beta 4 integrins in lesional and non-lesional skin in bullous pemphigoid.

The alpha 6 beta 4 integrin is associated ultrastructurally with the hemidesmosomes of the basal keratinocytes and with the bullous pemphigoid antigen (BPA), suggesting an important role in adhesion of epidermal cells to the basement membrane. Using an immunofluorescence technique with chain-specific monoclonal antibodies to the alpha and beta subunits we have investigated the distribution of the alpha 6 beta 4 integrin in normal skin (n = 3) and in BP skin (uninvolved, perilesional and lesional) [n = 11]). The findings have been compared with other types of subepidermal blisters and with normal skin split by chemical means (n = 2) and by suction (n = 2). The distribution of alpha 6 beta 4 integrin was compared with that of bullous pemphigoid antigen (BPA) and with other basement membrane zone (BMZ) macromolecules, laminin, collagen type IV, collagen type VII and the BM600 antigen. In uninvolved, perilesional and early pre-blistered lesional BP skin the distribution of both the alpha 6 and beta 4 integrin subunits, BPA laminin, collagen types IV and VII and the BM600 antigen was identical to normal skin, i.e. a linear band in the BMZ. Within BP blisters, both alpha 6 and beta 4 integrin subunits and BPA were absent, except in two blisters in which the integrin expression was retained in the blister roof, despite loss of BPA. The other BMZ components were expressed on the blister floor.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1992

Endometrial responses in artificial cycles: a prospective study comparing four different oestrogen dosages.

OBJECTIVE: To examine the endometrial response to four different regimens of oestrogen. DESIGN: A prospective, randomized cross-over study. SETTING: Jessop Hospital for Women, Sheffield. SUBJECTS: Twenty one women with premature ovarian failure divided into three equal groups. INTERVENTIONS: Four different regimens of hormone replacement therapy: variable, fixed 1 mg, fixed 2 mg and fixed 4 mg oestrogen dosages. Each woman received the variable dosage regimen in one cycle and crossed over to receive one of the three fixed dose regimens (1 mg, Group 1; 2 mg, Group 2; 4 mg Group 3) in another cycle. MAIN OUTCOME MEASURE: Ultrasonographic measurement of endometrial thickness and outpatient endometrial biopsy on day 19 of the artificial cycle; analysis of endometrial specimens by three separate methods: traditional histological criteria, morphometry and immunohistochemistry. RESULTS: The endometrial response was similar in those treated with the variable and the fixed 2 mg or 4 mg dosage regimens. The response was suboptimal in those treated with the fixed 1 mg dosage regimen. CONCLUSIONS: Normal endometrial development requires adequate priming of the endometrium by oestrogen, which may be administered in a sequential, variable dosage fashion, or simply by a fixed daily dosage regimen. However, the minimum daily dose required is likely to be 2 mg of oestradiol valerate. No adverse effect on the endometrium was observed at a daily dose of 4 mg oestradiol valerate, which produced plasma levels of oestradiol above the reference ranges of the natural cycle.

Adult↗
PubMed1992

Variant choriocarcinoma (BeWo) cells that differ in adhesion and migration on fibronectin display conserved patterns of integrin expression.

Starting from the BeWo choriocarcinoma cell line, two stable variant cell lines (epi and lc) were isolated. Epi cells displayed an epithelioid colony morphology while lc were fibroblastoid. lc cells attached and spread on fibronectin-coated surfaces at significantly lower density of fibronectin than epi or the parent cell line. lc also migrated more efficiently to fibronectin in a trans-filter assay than either epi or parent cells. Integrin expression by the cell lines was investigated by flow cytometry and immunoprecipitation from surface-labelled cells with a panel of subunit-specific antibodies. Integrins alpha 2 beta 1, alpha 5 beta 1, alpha v beta 1 and alpha 6 beta 4 were detected in each case, and levels of expression were identical in the two variant lines. Anti-functional antibodies were used to probe the role of integrins in fibronectin- and vitronectin-mediated adhesion. Complete inhibition of adhesion to fibronectin was observed with anti-beta 1 antibody, and partial inhibition with anti-alpha 5, suggesting that integrin alpha 5 beta 1 is mainly responsible for the interaction. Adhesion to vitronectin was inhibitable using anti-alpha v and anti-beta 1 antibodies, suggesting that integrin alpha v beta 1 is active in these cells as a vitronectin receptor. There was a correlation between the altered morphology of the variant cells and alterations in the distribution of integrin alpha 6 beta 4 and laminin in monolayer cultures. The results support the idea that fibronectin may mediate the migratory behaviour of extravillous trophoblast in vivo. Switch to a more migratory phenotype may be mediated by the selective activation of integrins and altered interaction with basement membrane.

Antibodies, Monoclonal↗
PubMed1991

The effects of the antiprogesterone RU486 (Mifepristone) on an endometrial secretory glycan: an immunocytochemical study.

OBJECTIVE: To examine the effects of progesterone (P) receptor blockade by RU486 (Mifepristone; Roussel-Uclaf, Paris, France) on a secretory endometrial glycan recognized by monoclonal antibody D9B1. DESIGN: Retrospective comparison of endometrial biopsies from treated and untreated women from 2 to 8 days after the luteinizing peak (LH) peak. SETTING: Infertility clinic, Jessop Hospital for Women, Sheffield. PATIENTS: Twenty-two normal fertile women received the RU486. A control group of 44 normal fertile women were also assessed. INTERVENTIONS: RU486 was administered to 22 normal women during the first half of the luteal phase and an endometrial biopsy examined 3 days later. MAIN OUTCOME MEASURES: Immunohistochemistry was used to assess the production and secretion of the D9B1 epitope. RESULTS: When the drug was given 2 days after the LH peak, it prevented appearance of the epitope. When RU486 was administered 5 days after the LH peak, epitope already present in gland cells was subsequently secreted. CONCLUSIONS: These data suggest that production of the sialo-oligosaccharide is P-dependent, but secretion through established intracellular pathways is P-independent.

Adult↗
PubMed1991

Integrin alpha 6/beta 4 complex is located in hemidesmosomes, suggesting a major role in epidermal cell-basement membrane adhesion.

The alpha 6/beta 4 complex is a member of the integrin family of adhesion receptors. It is found on a variety of epithelial cell types, but is most strongly expressed on stratified squamous epithelia. Fluorescent antibody staining of human epidermis suggests that the beta 4 subunit is strongly localized to the basal region showing a similar distribution to that of the 230-kD bullous pemphigoid antigen. The alpha 6 subunit is also strongly localized to the basal region but in addition is present over the entire surfaces of basal cells and some cells in the immediate suprabasal region. By contrast staining for beta 1, alpha 2, and alpha 3 subunits was very weak basally, but strong on all other surfaces of basal epidermal cells. These results suggest that different integrin complexes play differing roles in cell-cell and cell-matrix adhesion in the epidermis. Immunoelectron microscopy showed that the alpha 6/beta 4 complex at the basal epidermal surface is strongly localized to hemidesmosomes. This result provides the first well-characterized monoclonal antibody markers for hemidesmosomes and suggests that the alpha 6/beta 4 complex plays a major role in epidermal cell-basement membrane adhesion. We suggest that the cytoplasmic domains of these transmembrane glycoproteins may contribute to the structure of hemidesmosomal plaques. Immunoultrastructural localization of the BP antigen suggests that it may be involved in bridging between hemidesmosomal plaques and keratin intermediate filaments of the cytoskeleton.

Animals↗
PubMed1991

The epidermal basement membrane in basal cell carcinoma: an immunohistochemical study.

An immunohistochemical study of basal cell carcinomas of varying histological type, using a panel of antibodies to constituents of the epidermal basement membrane, showed marked deficiencies in the expression of the antigens identified by the antibodies LH7.2, GB3 and G71. There was no correlation between loss of immunoreactivity to these antibodies and the histological features of the tumour.

Antibodies, Monoclonal↗
PubMed1991

Glycans as biochemical markers of human endometrial secretory differentiation.

Uterine fluid contains a mixture of glycoprotein components the quantity and composition of which vary during the menstrual cycle. Their analysis may give clues to the involvement of maternally derived components in modulating the state of the peri-implantation blastocyst and aid in assessing the differentiation of the endometrium in preparation for implantation. Endometrial epithelium also exhibits an apical glycocalyx, the composition of which varies with the state of tissue differentiation. Evidence from animal systems suggests that glycans may be involved in molecular recognition between the embryo and maternal surface at implantation. Lectins and monoclonal antibodies to glycan epitopes have been used as sensitive and specific probes to examine the carbohydrates associated with endometrial epithelium as a function of the ovarian cycle. Numerous glycan structures are detected specifically in epithelial cells. Hitherto unsuspected biosynthetic heterogeneity is present in the glands. A secretory sialokeratan sulphate epitope is described, the occurrence of which coincides with the implantation phase of the cycle.

Biomarkers↗
PubMed1990

An endometrial factor in unexplained infertility.

OBJECTIVE: To study a group of women with unexplained infertility to see whether they have a defect that is intrinsic to the endometrium. DESIGN: Evaluation of the functional response of the endometrium by examining endometrial biopsy specimens using immunohistochemical methods in a group of women with unexplained infertility and in a control group of women with normal fertility. PATIENTS: 27 Women with unexplained infertility (average age 33.2); median duration of infertility five years. A control group of 44 women with normal fertility (average age 33.8) who were requesting sterilisation or reversal of sterilisation. SETTING: Infertility clinic, Jessop Hospital for Women, Sheffield. INTERVENTION: Secretory phase endometrial biopsy specimens were taken, with informed consent, as an outpatient procedure. MAIN OUTCOME MEASURES: Immunohistochemistry with monoclonal antibody D9B1, was used to assess the production and secretion of an oligosaccharide epitope produced by endometrial gland cells between two and seven days after the luteinising hormone surge. A reflected light measuring system was used to assess the amount of epitope within the gland cells, and in the gland lumen. RESULTS: In the control group of women, mean reflected light measurements at the cell base and cell apex peaked at three and five days after the luteinising hormone surge respectively, and in the gland lumen the epitope accumulated rapidly from three days, reaching a peak at seven days. In the women with infertility the peaks of epitope at the cell base and cell apex were lower, broader, and delayed in onset, and the build up of epitope in the gland lumen was retarded. The synthesis and secretion of the epitope in the women with infertility was therefore significantly reduced and delayed, even in the presence of normal concentrations of circulating progesterone. CONCLUSIONS: The results suggest that a primary dysfunction of the endometrium might be associated with hitherto unexplained infertility.

Adult↗
PubMed1990

Abnormal expression of G71 antibody at the epidermal basement membrane in basal cell carcinoma.

The antibody G71 is a murine monoclonal antibody directed against an antigen in the basement membrane zone of many human epithelia. Ultrastructurally it is located in the lamina lucida. The epitope is carried on glycoprotein components with molecular weights of 160, 125 and 115 kilodaltons. The authors examined the immunohistochemical expression of G71 antigen, using a standard indirect immunoperoxidase technique, in benign and malignant tumors derived from the epidermis. G71 staining was consistently absent or reduced around basal cell carcinomas (n = 44). In contrast, G71 was present at the basement membrane zone of squamous cell carcinomas (n = 18) and was also frequently expressed within the cytoplasm and on the cell surface of the malignant keratinocytes. The staining pattern of G71 at the basement membrane zone was essentially normal in keratoacanthomas (n = 10), solar keratoses (n = apart from foci of attenuation. In both seborrheic keratoses and intraepidermal squamous 13), seborrheic keratoses (n = 6), and intraepidermal squamous cell carcinomas (n = 8), cell carcinomas cell-surface and cytoplasmic staining were inconstant features. In conclusion, there appears to be a specific defect of G71 antigen expression in basal cell carcinomas.

Antibodies, Monoclonal↗
PubMed1990

Menstrual-cycle-dependent expression of keratan sulphate in human endometrium.

Immunochemical methods have been used to detect and characterize two classes of polypeptide-associated keratan sulphate (KS) in epithelial secretions from human endometrium. Monoclonal antibody D9B1 binds to a hormonally regulated sialylated epitope associated with KS in a high relative molecular mass (250,000-350,000) component that bands as a doublet in SDS/PAGE. These KS chain(s) are sensitive to keratanase, endo-beta-galactosidase and N-glycanase. A second, more highly sulphated, type of KS is also present, that is resistant to all three enzymes. This can be detected using monoclonal antibody 5D4. It is present throughout the menstrual cycle and is associated principally with a component of Mr 140,000. Thus secretory KS contributes to the environment of the implanting embryo, may be used as a molecular index of endometrial function and could be important in the establishment of pregnancy.

Animals↗
PubMed1989

A novel approach for monitoring the endometrial cycle and detecting ovulation.

We report the presence of a cycle-dependent sialoglycoprotein in the endometrium. A monoclonal antibody (D9B1) to this glycoprotein has been derived and used to study tissue from 24 women with normal menstrual cycles. Results obtained with peroxidase immunohistochemistry suggest a highly significant variation in concentration of the glycoprotein, which is absent in the proliferative phase and present at maximal levels in the early secretory phase. The amount of antigen then diminishes slowly through the latter part of the secretory phase. The glycoprotein is produced in epithelial cells of glands and uterine lumen before being secreted across the apical cell surface. The secretory response is uniform in different areas of the tissue and within individual glands. However, considerable differences in secretory activity can be observed between adjacent glands in any part of the endometrium. Binding of the antibody is shown to be a new and novel parameter in characterization and standardization of the normal function of endometrium in response to ovarian hormones.

Antibodies, Monoclonal↗
PubMed1989

The effect of the intrauterine contraceptive device on endometrial secretory function: a possible mode of action.

The effect of the intrauterine contraceptive device (IUD) on the composition of endometrial secretion has been studied using the monoclonal antibody D9B1. The antibody binds to a polypeptide-associated oligosaccharide epitope that is secreted by endometrial epithelium in the secretory phase with a maximum around the time of implantation. In endometria affected by the IUD in situ, a significant reduction in epitope expression has been observed using immunohistochemistry. This defect can occur against a background of normal secretory differentiation and in the expectation of normal ovarian stimulus. The data provide new insight into the contraceptive mechanisms of action of the IUD.

Adult↗