Biomedical subjects

R F Searle

Publications and source records attributed to R F Searle.

At least 37 records · Page 2Linked to original sources

PubMed1996

Immunohistochemical characterization of stromal leukocytes in ovarian endometriosis: comparison of eutopic and ectopic endometrium with normal endometrium.

OBJECTIVE: To compare stromal leukocyte subpopulations in different phases of the menstrual cycle in eutopic and ectopic endometrium from women with ovarian endometriosis and in control endometrium. DESIGN: Retrospective immunohistochemical study. SETTING: Department of Pathology, Royal Victoria Infirmary, Newcastle-upon-Tyne, United Kingdom. PATIENTS: Paraffin-embedded tissue blocks from 30 patients with endometriosis and 30 control blocks from patients undergoing hysterectomy for nonendometrial pathology were retrieved from archive files. MAIN OUTCOME MEASURE: Quantitative assessment of defined stromal leukocyte subpopulations in eutopic, ectopic and control endometrium at different stages of the menstrual cycle. RESULTS: In the proliferative and early secretory phases, ectopic endometrium contained elevated numbers of CD45+, CD3+, and CD43+ cells but reduced percentages of CD68+ macrophages. The proportions of granulated cells were reduced in ectopic endometrium throughout the cycle. No differences were noted between eutopic endometrium from women with endometriosis and control endometrium. CONCLUSION: Differences between eutopic and ectopic leukocyte subpopulations with the exception of large granular lymphocytes may be due to the lack of cyclicity demonstrated by endometriotic lesions.

Endometriosis↗

PubMed1995

Ultrastructural changes in cultured human periodontal ligament cells exposed to dental materials.

The cytopathic effects of a range of dental restorative cements were examined by electron microscopy using an in vitro model with cultured test cells derived from human periodontal ligament. Monolayers were fixed and processed in situ after 2, 24, and 48 h exposure. Many cells showed lysis after two hours exposure consistent with immediate acute injury. Cultures subsequently recovered, reflecting different susceptibilities of cells to injury, and at later stages showed distinct patterns of cell damage in response to different restorative materials. These were related primarily to either cytoplasmic or nuclear damage and to changes resembling apoptosis.

Apoptosis↗

PubMed1995

Morphological changes in cultured human periodontal ligament cells exposed to dental materials.

The cytotoxicity of a range of dental restorative cements was assessed by continuous observation of cultures with inverted microscopy and by light microscopic study of fixed preparations, using an in vitro model with cultured test cells derived from human periodontal ligament. The sequential morphological changes observed over a seven day period showed different degrees of cell loss and patterns of injury in response to different restorative materials, reflecting primarily either nuclear or cytoplasmic damage. Attempts at recovery were frequently identified as the culture period was extended and were characterized by recolonization of denuded areas of the culture well. It was concluded that differing dental cements damage cells through a variety of mechanisms and that the test cells exhibit differing degrees of susceptibility to injury. Assays based on short-term cultures may overestimate cytotoxicity by not allowing for cell recovery from reversible injury or repopulation of monolayers by proliferation of resistant cells.

Acrylic Resins↗

PubMed1995

Immunohistochemical characterization of proliferation, oestrogen receptor and progesterone receptor expression in endometriosis: comparison of eutopic and ectopic endometrium with normal cycling endometrium.

Recent studies examining oestrogen and progesterone receptor status and the proliferative activity of endometriotic lesions have produced conflicting reports. This study aimed to clarify the receptor status and proliferative activity of eutopic and ectopic endometrium from women with endometriosis and endometrium from normal women. Progesterone and oestrogen receptor expression and proliferative activity were studied in eutopic and ectopic endometrium from 30 women with endometriosis and in endometrium from 30 normal cycling women using microwave-pretreated paraffin-embedded sections stained with an avidin-biotin peroxidase technique. Progesterone and oestrogen receptor expression in the control endometrium did not differ from that of eutopic endometrium from women with endometriosis. Oestrogen receptor expression in ectopic endometrium increased from the proliferative to the late secretory phase. Epithelial progesterone receptor expression decreased during the cycle. Oestrogen receptor expression in both epithelium and stroma of ectopic endometrium was significantly higher than in eutopic endometrium throughout the cycle. In contrast, stromal progesterone receptor expression tended to be reduced in ectopic endometrium compared with eutopic tissue. Epithelial progesterone receptor expression was increased in ectopic endometrium but only in the late secretory phase. Although proliferative activity in the epithelium of control and eutopic endometrium was reduced from the proliferative to the late secretory phase, stromal activity did not vary. The proliferative activity in ectopic endometrium remained low and constant throughout the cycle. In the proliferative and early secretory phases, the proliferative activity of eutopic endometrium was increased compared with ectopic endometrium, but in the late secretory phase, levels were comparable. These findings challenge previous reports which have suggested that oestrogen receptors are reduced in ectopic tissue. This may have clinical implications for the development of novel treatments for endometriosis.

Case-Control Studies↗

PubMed1994

The immunomodulatory activity of human amniotic fluid can be correlated with transforming growth factor-beta 1 (TGF-beta 1) and beta 2 activity.

The role of alphafetoprotein (AFP) in the immunomodulatory activity of amniotic fluids (AF) from normally progressing human pregnancy (weeks 14-16) was investigated. A panel of 42 AF (25% v/v) reduced significantly phytohaemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMC) proliferation in serum-free cultures with a mean per cent inhibition of 68.4 +/- 5.5%. In contrast, AFP preparations, with one exception (U.AFP), failed to display inhibitory activity. Pretreatment of AF with anti-TGF-beta 1 and beta 2 antibodies used alone resulted in the mean per cent loss of inhibition of 33.1 +/- 3.9% and 52.3 +/- 7.5%, respectively. A summative loss of AF-mediated inhibition was detected when anti-TGF-beta 1 and beta 2 antibodies were used in combination, but immunomodulation was rarely abolished 100% by this treatment. Anti-TGF-beta 2 antibody treatment, unlike anti-TGF-beta 1 antibody treatment, reversed the inhibitory activity of U.AFP. The amount of TGF-beta 1 and beta 2 contained in human AF was studied by growth inhibition of Mv1 Lu cells. The mean levels of TGF-beta 1 and beta 2 in AF were 11 +/- 0.9 U/ml and 2.3 +/- 0.4 U/ml, respectively, which corresponds with a mean per cent inhibition of 49 +/- 4.7%. U.AFP also significantly inhibited Mv1 Lu cell growth. To investigate the mechanism of AF-mediated inhibition, the effect of AF and AFP on IL-2 production by concanavalin A (Con A)-stimulated PBMC blasts was determined by the CTLL-2 cell bioassay. IL-2 production was reduced 55.5% in AF-treated blasts and 61% in U.AFP-treated blasts compared with controls. Our findings indicate that the immunomodulatory activity of human AF can be correlated with TGF-beta 1 and beta 2 and not with AFP, the inhibitory activity of U.AFP preparation reflecting copurifying TGF-beta 2 activity.

Amniotic Fluid↗

PubMed1994

Cytotoxicity studies of dental restorative materials using human periodontal ligament cells in vitro.

A model that simulates conditions of clinical practice in vivo and allows extended exposure of test cells to test substances, was evaluated in vitro by screening the toxicity of seven dental restorative cements. Millipore filter discs, 0.45 micron pore size, or preserved dentine slices were used as diffusion barriers between test cells and test substances. Cytotoxicity was assessed by estimating cell loss from monolayers and by evaluating cytopathic changes in cultured cells. After 24 h exposure to the test materials results were in general agreement with reported observations from similar studies. However, extended exposure to composite resins gave rise to severe cytotoxicity, which has not been reported previously. In addition, monitoring of cultures by inverted microscopy demonstrated attempts at recovery in damaged monolayers with viable cells migrating and proliferating into areas of earlier cell loss. This supports observations in vivo of transient pulpal injury associated with the corresponding materials.

Acrylic Resins↗

PubMed1993

Cultural and morphological characteristics of human periodontal ligament cells in vitro.

Primary cell lines from explants of human periodontal ligament were established in vitro to assess their suitability as test cells in a biocompatibility assay. They were maintained over nine passages. The constituent fibroblast-like cells (F-cells) were monitored throughout by light and electron microscopy. Although F-cells from several different donors displayed stable and consistent growth characteristics, after the ninth subculture changes in the fine structure suggested that some cells were undergoing differentiation or senescence. It is therefore recommended that cells from earlier passages be used in in vitro biocompatibility assays.

Adolescent↗

PubMed1992

Antigen presenting capacity of human decidua: no evidence for human decidual antigen presenting cell mediated immunoregulation.

Decidual antigen presenting cell (APC) mediated maternal immunoregulation has been reported. In the present study the ability of villous chorion as well as fetal cell pulsed early human pregnancy decidual APC to generate selectively antigen non-specific and MHC class II unrestricted CD8 positive T suppressor cells was reassessed in view of the fact that placental trophoblast, unlike the fetus, constitutes the fetal tissue of major contact at the maternal-fetal interface. Neither fetal cell nor villous chorion pulsed decidual APC generated maternal T cells with the ability to immunosuppress PHA-, Con A- and PWM-induced autologous or allogeneic lymphoproliferation. In only 2 out of 45 assays with villous chorion pulsed decidual APC was significant inhibition of mitogen induced lymphoproliferation detected and on no occasion with fetal cell pulsed decidual APC. No change in CD4/CD8 ratio of the maternal putative regulatory cells was detected by FACS analysis compared with control cultures. These findings suggest that decidual APC mediated immunoregulation plays no role in directing the maternal immune response.

Antigen-Presenting Cells↗

PubMed1990

Induction of oncofetal antigen-specific suppressor pathways, involving Thy-1+ cells, during the early stages of tumor progression.

The early stages of tumor progression were modelled by intraperitoneally injecting BALB/c mice daily with exponentially increasing numbers of mitomycin C-treated, syngeneic MPC-11 tumor cells. At various stages of this regime, mesenteric lymph node (MLN) and spleen cells were assessed for regulatory activity on the induction of cytotoxic T lymphocytes (CTL) in vitro. Cells present in both MLN and spleens of mice whose daily tumor dose had reached 102,400 MPC-11 cells impaired the generation of CTL specific for MPC-11 and specific for oncofetal antigen(s) shared between MPC-11 and Day 14-15 syngeneic fetal liver cells. Depletion of Thy-1+ cells from the regulatory cell populations removed the suppressive activity. The regulatory cells did not affect the induction of CTL specific for H-2b antigens in the context of H-2d (i.e., BALB/c) class I MHC.

Animals↗

PubMed1989

Natural killer (NK) cell activity of first trimester human decidua.

The NK cell functional capacity of first trimester human decidua against K562 targets was assessed in a 3-hr CRA. Collagenase dispersal combined with plastic adherence, nylon wool passage, and density gradient centrifugation yielded NKH-1 (Leu 19) positive enriched decidual large granular lymphocyte fraction (mean 75% positive). Decidual effectors displayed reduced lytic activity compared with autologous PB effectors at every effector:target ratio but this difference in cytotoxicity was abolished by short-term culture before the CRA. Decidual effectors treated with 50 units rIL-2 showed increased lytic activity compared to untreated decidual cells. By FACS analysis the majority of NKH-1 positive decidual effectors were CD3 and CD16 negative which corresponds with a minority PB NK population. The implications of a population of functional NK cells in early pregnancy decidua for the materno-fetal relationship is discussed.

Antibodies, Monoclonal↗

PubMed1988

Antigen presenting capacity of murine decidual tissue in vivo.

Antigen presenting cells (APC) within murine decidual tissue in vivo have been shown to process the soluble antigen ovalbumin after intravenous administration and to present it in a form recognizable by immune T lymphocytes. In vivo antigen pulsed decidual APC stimulated T cell proliferation as efficiently as splenic APC and in an MHC restricted manner. In addition, anti-class II antibody plus complement treatment significantly reduced decidual antigen presenting capacity in vitro. These findings show that class II positive cells within the decidua can present antigen effectively in vivo and may therefore serve as APC for the presentation of fetal antigens to the maternal immune system during pregnancy.

Animals↗

PubMed1988

Alloantigen presenting capacity of human decidual tissue.

The capacity of first trimester human decidua-derived cells to serve as accessory cells for the presentation of alloantigens to unprimed T lymphocytes was assessed using a mixed lymphocyte culture (MLC) between accessory cell-depleted responder and stimulator peripheral blood lymphocytes (d PBL). In all of the seven experiments performed decidua-derived cells achieved significant reconstitution of the lymphoproliferative response between autologous responder and stimulator dPBL. Reconstitution indices (RIs) ranged between 3.1 and 22.2 and were significant in all cases. In six out of the seven experiments the level of lymphoproliferation exceeded that between untreated responder PBLs co-cultured with stimulator d PBL. Substitution of recombinant interleukin 1 (rIL-1) alpha or beta for the decidua-derived cells resulted in significantly lower RIs than those achieved by the decidua-derived cells. These findings suggest that decidua-derived cells can serve as antigen presenting cells for the presentation of membrane-bound alloantigens in a primary lymphoproliferative response. This may have implications for maternal recognition of fetal antigens during first pregnancy.

Antigen-Presenting Cells↗

PubMed1987

The role of prostaglandins in the immunosuppressive effects of supernatants from adherent cells of murine decidual tissue.

Supernatants from short-term cultures of murine decidual tissue (DS) were assessed for their regulatory effects on T cell lymphoproliferation and cytotoxic T lymphocyte (CTL) activity. DS non-specifically suppressed antigen- and mitogen-induced lymphoproliferation, spontaneous thymocyte proliferation, the mixed lymphocyte reaction (MLR) and CTL generation, but had no effect on CTL lytic activity. The immunosuppressive activity was lost after dialysis (14 kDa cut off). Supernatants from indomethacin-treated decidual tissue cultures (indomethacin-DS) lacked suppressive activity in the MLR, mitogen and thymocyte proliferation assays. Indomethacin-DS also showed markedly reduced or no suppressive effects on CTL generation. These findings suggest that prostaglandin production by the decidual component of the placenta could play a role in materno-fetal cellular interactions by regulating T cell lymphoproliferative responses and CTL generation.

Animals↗

PubMed1986

Effect of amphotericin B on human periodontal ligament cells cultured in vitro.

Three micrograms of amphotericin B/ml nutrient medium markedly inhibited the monolayer outgrowth of cells from explants of human periodontal ligament. Amphotericin B (1.5 microgram/ml) retarded outgrowth with morphological evidence of cell injury. The addition of 3 micrograms/ml amphotericin B to existing monolayers initially caused disruption of the majority of cells but those which survived then proliferated. Thus, routine use of amphotericin B is contra-indicated in tissue culture of human periodontal ligament.

Amphotericin B↗

PubMed1985

Detection of macrophages and the characterization of Fc receptor-bearing cells in the mouse decidua, placenta and yolk sac using the macrophage-specific monoclonal antibody F4/80.

A mouse macrophage-specific rat monoclonal antibody, F4/80, has been used to detect directly macrophages in short term cultures of mouse decidua, fetal placenta and yolk sac and to investigate the identity of Fc receptor (FcR) bearing cells in these tissues. We find that a significant proportion of FcR positive cells in decidual, placental and yolk sac tissues are macrophages as defined by the expression of the macrophage marker, F4/80 antigen. Macrophages may act as immunocompetent cells near to the maternal-fetal interface and play a significant role in the mechanism of the transfer of passive immunity from mother to fetus across the mouse yolk sac.

Animals↗

PubMed1985

Antigen-presenting capacity of mouse decidual tissue and placenta.

The antigen-presenting capacity of cells within mouse decidual tissue and the fetal placenta was assessed using the antigen-presenting cell assay to measure immune T cell proliferation stimulated by a second presentation of antigen. Cells within decidual tissue bind and present the soluble antigen dinitrophenylated ovalbumin in an antigen-specific and major histocompatibility complex-restricted manner. Antigen-presenting cells (APCs) were detected in decidual tissue from day 8 until day 15 of pregnancy, in deciduoma and in fetal placental tissues. These findings show that cells within decidual tissue may serve as APCs with the ability to process and present fetal antigens to the maternal immune system and may therefore determine the direction of the maternal immune response of pregnancy.

Animals↗

PubMed1984

Cell-mediated immunity to male-strain histocompatibility alloantigens detected after natural insemination and systemic immunization in the female mouse using the cell-mediated microcytotoxicity test.

Female cell-mediated immunity to allogeneic spermatozoa after repeated natural insemination, in the absence of pregnancy, was compared with that after systemic challenge using the cell-mediated microcytotoxicity test to measure cytotoxic cell alloreactivity. After multiple (3-6) inseminations the majority of females (11 out of 13) showed a significant degree of lymphocytotoxicity to male-strain histocompatibility alloantigens in the para-aortic lymph nodes, and to a lesser extent in the spleens, while a single insemination was usually not sufficient to evoke a specific cytotoxic cell response. This differed from the low and highly variable degree of female sensitization after multiple systemic challenge with allogeneic spermatozoa via the intraperitoneal route. By contrast, a single systemic challenge via the footpad proved to be the most highly consistent and effective route for eliciting cell-mediated immunity to male-strain histocompatibility alloantigens in all 9 female mice. This alloreactivity appeared to be directed at alloantigens other than the male-specific H-Y antigen. These findings show that the precise route of immunization is a major factor in the development of female cell-mediated immune responsiveness to allogeneic spermatozoa.

Animals↗

PubMed1981

Differentiation of decidual cells in mouse endometrial cell cultures.

Mouse uterine cells were obtained by trypsinization of uteri at timed intervals after the induction of a decidual reaction by intraluminal instillation of arachis oil on Day 4 of normal pregnancy. Cells were also obtained from ovariectomized mouse uteri, some of which had received a progesterone-oestradiol sequence to sensitize the uterus to a decidual stimulus. The differentiation of decidual cells was followed in cultures of these cells. The morphology of the cells obtained after 6 days in culture was dependent upon the seeding density employed. At low seeding density (plating densities of 75-100 cells/mm2) no net increase in cell number was observed, but large mononucleated stellate cells were present, with cytoplasmic and nuclear areas increased by 4-fold. At higher seeding densities (plating densities of up to 709 cells/mm2), a prolongation of cell survival and the appearance of substantial numbers of binucleated cells were observed. However, both cell types were characterized by the accumulation of filamentous material in the cytoplasm. Even at optimal seeding density the life-span of the decidualized cells could not be prolonged beyond 9 days. Uterine cells from hormone-treated ovariectomized animals underwent similar transformations but those from untreated ovariectomized mice gave only isolated islets of epithelial cells and scattered fibroblast-like cells in culture. These observations suggest that discrepancies in previous reports of in-vitro deciudualization of rat uterine cells result from differences in the seeding densities employed.

Animals↗