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Biomedical subjects

R F Searle

Publications and source records attributed to R F Searle.

50 records · Page 3Linked to original sources
PubMed1978

Localization of trophoblast-defined surface antigens during early mouse embryogenesis.

The binding pattern of a rabbit antiserum raised against mouse-ectoplacental-cone trophoblast on component cell populations in the pre-implantation and early post-implantation mouse embryo has been examined at the electron-microscope level using an immunoperoxidase-labelling technique. Binding was not detectable on the 1-cell stage, appeared at low levels at the 8-cell stage and was heavy on the trophectoderm and its trophoblast giant cell and extra-embryonic ectoderm descendants in the post-implantation embryo. In contrast, immunosurgically isolated 3 1/2-day inner cell masses (ICM) showed only slight labelling, whilst ICM derivatives in the 7 1/2-day embryo were unlabelled. The results indicate that the antiserum may be identifying a trophoblast-specific surface determinant(s), which appears with the differentiation of the trohectoderm and is maintained on some of the cell populations derived from this tissue at least until the early post-implantation stages.

Animals↗
PubMed1976

Detection of alloantigens during preimplantation development and early trophoblast differentiation in the mouse by immunoperoxidase labeling.

An immunoperoxidase-labeling technique allowing visualization of antibody binding to the cell surface at the electron microscopical level has been employed an an analysis of H-2 and non-H-2 alloantigen expression on the early mouse embryo. The presence of non-H-2 antigenic determinants has been confirmed on eight-cell, morula, and blastocyst stages of development. Contrary to previous reports, however, low levels of H-2 antigen have also been detected on the blastocyst. This is the earliest stage at which H-2 has been shown to be expressed on the fertilized mouse egg and may reflect the greater resolution of the immunoperoxidase technique. Using two different models to study the critical peri-implantation stages, those of experimentally induced blastocyst activation and blastocyst outgrowth in vitro, it has been demonstrated that antigen loss occurs on the trophectoderm at the time of implantation, and that this is not necessarily dependent upon maternal influence. It is suggested that the loss may be an important factor in the prevention of maternal immune rejection during the establishment of the fetal allograft. The two major components of the early postimplantation conceptus display a striking differential in antigenic status. The embryonic sac shows a high degree of peroxidase labeling, while the ectoplacental cone trophoblast is unlabeled. These findings add support to the concept of antigenic neutrality of the early trophoblast and its role in the maintenance of a normal fetomaternal immunological equilibrium.

Animals↗
PubMed1976

A technique for liver transplantation in the inbred mouse.

The technique of liver grafting to the kidney of inbred mice was used to characterise ultrastructurally liver rejection under controlled conditions. Electron microscopy showed that liver rejection was initiated by intimate contract between the hepatocytes and the infiltrating large lymphoid cells and brought about by means of narrow cytoplasmic processes extended from the latter. This was prevented by ATS-immunosuppressive treatment.

Animals↗
PubMed1976

An electron microscopic study of pig liver viability after extracorporeal storage.

The effects of hyperbaric oxygenation and ambient pressure oxygenation on the viability of pig liver stored in the Vickers' transportable organ storage unit were assessed by electron microscopy. It was found that hyperbaric oxygenation resulted in marked liver damage in contrast to ambient pressure storage. Although electron microscopy proved to be a sensitive method for detecting damage induced by unsuitable storage protocols consideration is given to the possibility that other changes, which may not be detectable by electron microscopy, limit the success of liver storage.

Animals↗
PubMedDate not supplied

Differential expression of class II major histocompatibility complex and Thy 1.2 antigens on mouse decidua.

A differential expression of class II major histocompatibility complex (MHC) and Thy 1.2 antigens was detected on two morphologically distinct cell populations in short-term cultures of murine decidual tissue. Stromal type decidual cells expressed Thy 1.2, albeit transiently, and consistently lacked class II antigens. By contrast decidual macrophages expressed class II antigens and lacked Thy 1.2 antigens. Stromal type decidual cells, after culture in the presence of indomethacin, displayed no evidence of prostaglandin-mediated modulation of class II expression. These findings suggest that class II positive decidual macrophages are responsible for the antigen-presenting capacity of decidua.

Animals↗
PubMedDate not supplied

Ia antigen expression on the developing mouse embryo and placenta.

The expression of I region controlled antigens on the mouse embryo and placenta has been investigated using immuno-peroxidase labelling and a mixed haemadsorption assay. The results indicate that Ia antigens are absent from selected pre- and post-implantation embryonic and trophoblastic tissues and from the trophoblast of the definitive placenta. In contrast, cells derived from the peri-placental maternal decidual tissues are Ia antigen-positive. The findings are discussed in relation to the allograft status of the conceptus and the identity and functional significance of the Ia-bearing maternal cells at the foeto-maternal interface.

Animals↗
PubMedDate not supplied

Detection of human and murine trophoblast-specific antigens and an assessment of their species specificity.

The distribution and species specificity of human and mouse trophoblast-specific surface antigens detected by heterologous anti-mouse ectoplacental cone (anti-EPC) trophoblast and anti-human first-trimester trophoblast plasma membrane (anti-TrPM) antisera were assessed using several immunochemical and immunolabelling assays. The findings with immunofluorescence assays using anti-EPC antiserum on monolayer cultures indicate that the expression of mouse trophoblast-specific antigens is restricted to the major trophoblast components of the mouse placenta, as well as pre- and early post-implantation trophoblast, and does not occur on fetal, amnion or tumour tissues. The anti-EPC antiserum does not cross-react with human chorionic villous trophoblast. The human trophoblast-specific antigens also displayed species specificity. The anti-TrPM antiserum showed no evidence of cross-reactivity with rhesus monkey, rabbit, guinea pig or mouse trophoblast by immunodiffusion, crossed immunoelectrophoresis, immunofluorescence or immunoperoxidase labelling.

Animals↗
PubMedDate not supplied

Ia antigen-bearing decidual cells and macrophages in cultures of mouse decidual tissue.

The ontogeny of Ia antigen expression on cells within the decidua basalis of the placenta and on decidual cells differentiating in vitro was investigated in the mouse. The results indicate that Ia antigen expression is temporarily restricted and can be detected in short-term cultures of decidual tissue only during the final third of gestation. The Ia antigen positive cells, which are non-phagocytic, non-specific esterase negative and lack Fc receptors, appear to be true decidual cells on the basis of their fine structural characteristics. In contrast, morphologically identical dendritic decidual cells arising from differentiation in vitro of endometrial cells do not express Ia antigens. A population of small rounded cells was also present in cultures of both decidual tissue and in vitro decidualized endometrial cells. These rounded cells possess the macrophage-like properties of Fc receptors, non-specific esterase and phagocytic activity. The possible function of these cell populations within the decidual tissue is discussed.

Animals↗
PubMedDate not supplied

Phenotypic and functional studies of leukocytes in human endometrium and endometriosis.

The aetiology of endometriosis, a common and disabling disorder, is presently unknown, although immune dysfunction could allow ectopic endometrial fragments to survive outside the uterine cavity. These studies investigate the relationship between leukocyte populations, steroid hormone receptor expression, proliferative activity, bcl-2 expression and apoptosis in eutopic and ectopic endometrium from women with endometriosis or adenomyosis at different phases of the menstrual cycle. Significantly increased oestrogen receptor expression, bcl-2 expression and numbers of CD8+ leukocytes were found in ectopic compared with eutopic endometrium in endometriosis, and CD56+ endometrial granulated lymphocytes (eGLs) were significantly reduced in ectopic endometrium. Apoptotic cells were rarely found in control and subject endometria. In contrast with endometriosis, adenomyotic lesions showed identical steroid hormone receptor expression, proliferative activity, bcl-2 expression and leukocyte subpopulations to eutopic endometrium, indicating different aetiologies for these disorders. The unusual CD56+ CD16- eGLs present in large numbers in late secretory phase eutopic endometrium were highly purified (>98%) by immunomagnetic separation. Except for a negligible cytotoxic activity of eGLs from early proliferative samples, cytotoxic activity of eGLs from non-pregnant endometrium during the menstrual cycle was comparable with those in peripheral blood, predominantly CD56+ CD16+ natural killer cells. eGLs from non-pregnant endometrium and early pregnancy showed a variable proliferative response to 5 and 100 U/ml interleukin-2 over 48-h and 120-h time courses. eGLs are evidently functionally important in the eutopic endometrium. Their absence in endometriotic lesions together with increased CD+8 T-cell numbers and increased oestrogen receptor and bcl-2 expression may have significant effects on the development and progression of endometriosis.

Antigens, CD↗