Interaction of immunosuppressive agents rapamycin and its analogue SDZ-RAD with endothelial P-gp.
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ATP Binding Cassette Transporter, Subfamily B, Mem↗
Biomedical subjects
G F Murphy
Publications and source records attributed to G F Murphy.
Mechanism of apoptotic regulation of follicular regression: toward understanding the molecular basis for tissue remodeling and regeneration.
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Animals↗
Vbeta spectratype analysis reveals heterogeneity of CD4+ T-cell responses to minor histocompatibility antigens involved in graft-versus-host disease: correlations with epithelial tissue infiltrate.
Lethal graft-versus-host disease (GVHD) can be induced after hematopoietic stem cell transplantation between major histocompatibility complex-matched murine strains expressing multiple minor histocompatibility antigen (miHA) differences. In the C57BL/6By (B6)-->C.B10-H2b/LiMcdJ (BALB.B) irradiation model, both CD4+ and CD8+ donor T cells can mediate lethal GVHD, whereas in the B6-->CXB-2/By (CXBE) model, in which the recipient expresses a subset of BALB.B miHA, only the CD8+ T cells are lethal. Phenotypic analysis of CD4+ T cells collected from the thoracic duct lymphocyte pool of recipient mice had indicated expansion of the donor T-cell receptor Vbeta6-9 families in BALB.B recipients, and only Vbeta7 and Vbeta9 populations in CXBE mice. CDR3-size spectratyping, used to further analyze these responses, revealed overlapping oligoclonal expansion of Vbeta4, Vbeta6-10, and Vbeta12-14 families in both BALB.B and CXBE recipients injected with host-presensitized B6 T cells. In addition, the B6-->BALB.B CD4+ T-cell response appeared to involve the recognition of unique BALB.B-specific miHA, indicated by additional skewing of Vbeta2 and Vbeta11 families. On the other hand, the B6-->CXBE strain combination exhibited unique skewing of the Vbeta16 and Vbeta18 families. Immunohistochemical staining of lingual epithelial sections from BALB.B recipients of naive B6 CD4+ T cells correlated with the involvement of several of the spectratype-skewed Vbeta families in GVHD lesions. Furthermore, magnetic cell separation techniques were used to positively select the spectratype-skewed Vbeta families from the donor B6 CD4+ T cells; the former were found to have significant GVHD potential upon transplantation into lethally irradiated BALB.B recipients. In contrast, mice that received transplants from the unskewed Vbeta families all survived with minimal symptoms of GVHD. Taken together, these results demonstrate that the expansion of particular Vbeta families, as identified by spectratype analysis, correlates with the induction and pathogenesis of lethal GVHD.
Animals↗
Fas ligand-deficient gld mice are more susceptible to graft-versus-host-disease.
BACKGROUND: The Fas/Fas ligand (FasL) pathway plays an important role in a number of apoptotic processes that could be important for the development of graft-versus-host disease (GVHD) after bone marrow transplantation (BMT), such as cytolysis of target cells by cytotoxic T cells, regulation of inflammatory responses, peripheral deletion of autoimmune cells, costimulation of T cells, and activation-induced cell death. METHODS: To study the role of the Fas/FasL pathway in the complex pathophysiology of graft versus host disease (GVHD), we used FasL-deficient B6.gld mice as recipients in a Major Histocompatibility Antigen Complex-matched minor Histocompatibility Antigen-mismatched murine model for GVHD after allogeneic BMT (C3H.SW-->B6). RESULTS: We found a significantly higher morbidity and mortality from GVHD compared to control B6 recipients. Histopathological analysis of the GVHD target organs demonstrated that B6.gld recipients developed significantly more thymic and intestinal GVHD. B6gld recipients with GVHD demonstrated an increased expansion of donor T cells and monocytes/ macrophages compared to control B6 recipients, whereas serum TNF-alpha levels were equivalent in B6.gld recipients and control B6 recipients. CONCLUSION: This study demonstrates that the expression of FasL in the BMT recipient is important for the host's ability to control GVHD.
Animals↗
NOF-11: a one-year pediatric randomized double-blind comparison of neoral versus sandimmune in orthotopic liver transplantation.
BACKGROUND: Although cyclosporine (CsA) has been a mainstay in liver transplantation immunosuppression the original formulation [Sandimmune (SIM)] has variable absorption, particularly in children. Neoral is a new formulation of CsA that may have improved biovailability that would be advantageous in children. This study was undertaken to assess the pharmacokinetics (PK) and effects on outcome of Neoral versus Sandimmune (SIM) in primary pediatric liver transplant recipients. METHODS: Thirty-two patients were randomized to receive Neoral (17 patients) or SIM (15 patients) in the early posttransplant period (days 1-7) in a double-blind fashion. Intravenous CsA was instituted immediately posttransplant followed by Neoral or SIM as soon as the patient was tolerating oral fluids (days 1-7). PK were compared after the first dose (1-7 days), 3 weeks, and 6 and 12 months posttransplant. In addition, side effects, effect of age and food on absorption, and rejection episodes were assessed by intent to treat analysis. Notable characteristics of this study include the use of a central laboratory for all sample analyses and the assessment of renal function using radioisotopic evaluation of glomerular filtration rates. RESULTS: At baseline the two groups were comparable. Neoral resulted in higher peak levels of CsA and total drug exposure with comparable time to peak drug levels at days 1-7 and week 3. This trend was maintained at 6 and 12 months. Time on i.v. CsA was reduced in the Neoral group (8.4 vs. 11.1 days) and the weight adjusted daily dose of SIM required to achieve target trough levels was about 2-fold more than Neoral from day 22 onward. In addition, biopsy proven and treated and steroid-resistant rejection episodes were fewer in the Neoral group (6 vs. 12; P=0.01 and 1 vs. 8: P=0.004, respectively). Side effects were comparable in both treatment groups. CONCLUSIONS: Neoral was well tolerated and had greater biovailability than SIM without any increase in the incidence of side effects. In addition fewer episodes of rejection were observed with Neoral versus SIM. We conclude that Neoral is the CsA formulation of choice for use in pediatric liver transplant recipients.
Child↗
Fas-deficient lpr mice are more susceptible to graft-versus-host disease.
The Fas/Fas ligand (FasL) pathway is involved in a variety of regulatory mechanisms that could be important for the development of graft-vs-host disease (GVHD) after bone marrow transplantation (BMT), such as cytolysis of target cells by cytotoxic T cells, regulation of inflammatory responses, peripheral deletion of autoimmune cells, costimulation of T cells, and activation-induced cell death. To further evaluate the role of Fas/FasL in the complex pathophysiology of GVHD, we used Fas-deficient B6.lpr mice as recipients in a MHC-matched minor histocompatibility Ag-mismatched murine model for GVHD after allogeneic BMT (C3H.SW-->B6). We found a significantly higher morbidity and mortality from GVHD compared with control B6 recipients. In contrast, B6.lpr recipients had very little hepatic GVHD, although all other specific GVHD target organs (skin, intestines, and thymus) were more severely affected than in the control B6 recipients. B6.lpr recipients with GVHD demonstrated intact donor lymphoid engraftment and an increase in expansion of donor T cells and monocytes/macrophages compared with control B6 recipients. Serum levels of IFN-gamma and TNF-alpha were higher in B6.lpr recipients than in control B6 recipients, and monocytes/macrophages in B6.lpr recipients appeared more sensitized. B6.lpr recipients had more residual peritoneal macrophages after BMT, and peritoneal macrophages from B6.lpr mice could induce a greater proliferative response from C3H.SW splenocytes. This study demonstrates that the expression of Fas in the recipient is required for GVHD of the liver, but shows unexpected consequences when host tissues lack the expression of Fas for the development of GVHD in other organs and systemic GVHD.
Animals↗
Cytological alterations in dermal dendrocytes in vitro: evidence for transformation to a non-dendritic phenotype.
Dermal dendrocytes (DDs) are bone marrow-derived cells which are abundant in normal human and murine dermis, where they are closely associated with mast cells in the perivascular space. The biological role of DDs remains enigmatic. DDs express coagulation factor XIIIa and the recently described von Willebrand factor receptor, GPIb alpha, potentially indicating a function in tissue repair and haemostasis, although participation in antigen presentation is also speculated. In healing wounds and 'fibrohistiocytic' tumours, such as dermatofibromas, DDs are often associated with non-dendritic histiocytes, some of which also express factor XIIIa (FXIIIa). We have utilized human skin organ culture to examine the effects of various biological mediators on cytological characteristics of DDs. It was found that by 24 h in organ culture, immunoreactive DDs begin to lose their dendritic shape, assuming more rounded contours. This phenomenon was accentuated by mast cell degranulation; was independent of the nature of mast cell secretagogue; and could not be reproduced by recombinant tumour necrosis factor-alpha, a cytokine known to increase FXIIIa expression in DDs. Like their dendritic precursors, non-dendritic cells expressed variable FXIIIa, CD34 and CD68 and did not express CD1a or CD45. By ultrastructure, non-dendritic cells that develop in vitro resembled non-degenerating monocytes containing occasional primary lysosomes and lipid inclusions, and like DDs, expressed fibronexus-like plaques on the cell membrane. Transition of DDs from dendritic to non-dendritic cells as a consequence of specific microenvironmental influences may provide insight into the frequent concurrence of these two cytological types in fibrohistiocytic tissue reactions and neoplasia.
Antigens, CD34↗
Mast cells and dendritic cells in basal cell carcinoma stroma.
BACKGROUND: The interaction of tumors with the surrounding stroma has become an important topic in tumor biology. Basal cell carcinoma (BCC) stroma has been characterized as hypervascular and rich in mast cells. The presence of dermal dendrocytes thought to have both antigen presenting and wound healing functions has recently been reported in BCC stroma. GP1b-alpha is a newly described vascular adhesion molecule with potential significance in tumor biology. OBJECTIVE: To further characterize the cellular phenotype of BCC stroma. METHODS: Eleven BCCs (8 nodular, 2 sclerosing, 1 adenoid-cystic) were examined using immunohistochemical techniques for the presence of antigens specific to vascular endothelium, mast cells, and dermal dendrocytes. RESULTS: The stroma of all BCCs demonstrated increased vascularity, increased numbers of mast cells, and increased numbers of dermal dendrocytes expressing both CD34 and GP1b-alpha adjacent to tumor nests. No differences in antigen expression were observed between histologic subtypes of BCC. CONCLUSION: The close proximity of stromal mast cells and dermal dendrocytes surrounding BCC nests suggests a biologically significant interaction. The pattern observed is similar to that observed in healing wounds.
Antigens, CD34↗
Angiomatoid melanoma: a novel pattern of differentiation in invasive periocular desmoplastic malignant melanoma.
A case of locally invasive, long-standing desmoplastic and amelanotic malignant melanoma is described in an 84-year-old man. Histologic examination of the involved periorbital tissue showed neoplastic foci exhibiting a novel pattern reminiscent of microvascular proliferation. These regions were characterized by malignant, S-100-positive tumor cells lining vessel-like spaces in transverse sections and forming tubuler-like structures in longitudinal sections. Recent data indicate that melanoma cells may express genes and patterns of differentiation in vitro akin to endothelial cells. Because angiosarcoma often involves facial and scalp skin of elderly individuals, awareness of angiomatoid differentiation in melanoma has important diagnostic implications. HUM PATHOL 31:1520-1522.
Aged↗
Prostatic adenocarcinoma metastasizing to the vocal folds.
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Adenocarcinoma↗
Dysplastic melanocytic nevi and prognostically indeterminate nevomelanomatoid proliferations.
This article reviews the concept of dysplasia and the distinguishing features of dysplastic nevi, including their premalignant potential, their biologic markers of tumor progression, and their reproducibly recognizable clinical and histologic characteristics. An additional emphasis is placed on describing gray zone melanocytic neoplasms with hybrid histopathologic and biologic characteristics between nevi and melanoma. In particular, dysplastic nevi with high-grade and dermal dysplasia and other potentially related, prognostically indeterminate, nevomelanomatoid proliferations (PINM tumors), including the more recently recognized nevoid melanoma and minimal deviation neoplasms, are discussed. Because of their overlapping features with more overtly benign and malignant neoplasms, these lesions may confound precise determination of biologic outcome. Accordingly, the concept of prognostic indeterminacy and the use of the term PINM tumors to connote these problematic lesions are introduced.
Biomarkers↗
Comparison of IgE and IgG antibody-dependent cytotoxicity in vitro and in a SCID mouse xenograft model of ovarian carcinoma.
Allergic reactions are mediated by IgE antibodies bound to high-affinity receptors on mast cells in peripheral tissues and are characterized by their immediacy and hypersensitivity. These properties could also be advantageous in immunotherapy against cancer growth in peripheral tissues. We have constructed chimeric IgE and IgG1 antibodies with murine V regions and human C regions corresponding to the MOv18 monoclonal antibody against the human ovarian tumor-associated antigen, folate binding protein. The antibodies exhibited the expected binding affinities for antigen and Fc receptors, and effector activities with human basophils and platelets in vitro. The protective activities of MOv18-IgE and MOv18-IgG1 were compared in a SCID mouse xenograft model of ovarian carcinoma. The beneficial effects of MOv18-IgE were greater and of longer duration than those of MOv18-IgG1. Our results suggest that the allergic reaction could be harnessed for the suppression of ovarian tumors.
Animals↗
Wallace H. Clark, Jr., MD: a biography and annotated bibliography.
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Dermatology↗
Recognition and evaluation of cytological dysplasia in acquired melanocytic nevi.
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Dysplastic Nevus Syndrome↗
Von Willebrand factor receptor GPIb alpha is expressed by human factor XIIIa-positive dermal dendrocytes and is upregulated by mast cell degranulation.
GPIb alpha, a glycoprotein component of the GPIb-IX-V complex, serves as a platelet membrane receptor that mediates adhesion to von Willebrand factor normally present in the vascular subendothelium. Recent data have demonstrated that GPIb alpha is not restricted to platelets, but is also expressed by endothelium in vitro. In this study, we describe the expression and distribution of GPIb alpha in normal adult and neonatal human skin. GPIb alpha is present, as detected by immunohistochemistry, on endothelial cells and on highly dendritic cells localized within the perivascular space, dermal-epidermal junction, and reticular dermis. By dual-labeling immunofluorescence and confocal microscopy, GPIb alpha-positive cells within the dermal interstitium are demonstrated to represent factor XIIIa-positive dermal dendrocytes. In organ cultures of neonatal human foreskin, mast cell degranulation induced by either substance P or compound 48/80 resulted in transiently increased GPIb alpha expression by dermal dendrocytes. Because the GPIb-IX-V complex plays a part in regulating hemostasis and may be important for cellular interactions with extracellular matrix molecules, these data provide additional insight into the potential function of FXIIIa-positive dermal dendrocytes in skin remodeling and repair.
Adult↗
Quantitative and ultrastructural analysis of inflammatory infiltrates in male pattern alopecia.
In order to determine whether lymphocytic inflammation around the lower infundibula in male pattern alopecia is incidental or a general phenomenon, we performed morphometric and ultrastructural analysis of inflammatory infiltrates in the transitional zones of the vertex and occipital hairy scalps of 19 patients with male pattern alopecia. Six normal subjects served as controls. The number of inflammatory infiltrates around the follicular infundibula of the alopecic vertices and non-alopecic occiputs of male pattern alopecia patients was significantly greater than the corresponding control value. The number of mast cells in the widened fibrous tracts in the vertices of male pattern alopecia patients was significantly greater than those in the adventitial fibrotic sheaths of control subjects and the non-alopecic occiputs of male pattern alopecia patients. These data support the idea that the inflammatory process may be, at least in part, responsible for the development of male pattern alopecia.
Adolescent↗
Targeted inactivation of the type VII collagen gene (Col7a1) in mice results in severe blistering phenotype: a model for recessive dystrophic epidermolysis bullosa.
Dystrophic forms of epidermolysis bullosa (DEB) are associated with mutations in the type VII collagen gene (Col7a1) which encodes the major component of anchoring fibrils. To develop a DEB animal model, type VII collagen deficient mice were generated by targeted homologous recombination. The targeting vector replaced exons 46-69 of Col7a1 with the neomycin-resistance gene, in reverse transcriptional orientation, resulting in elimination of most of the collagenous domain 1. Col7a1 heterozygous (+/-) mice were phenotypically normal. Mating of Col7a1 +/- mice revealed that Col7a1 null (-/-) mice, which were born with extensive cutaneous blistering, died during the first two weeks of life probably due to complications arising from the blistering. Transmission electron microscopy revealed subepidermal blistering below the lamina densa and absence of anchoring fibrils. Immunohistochemical staining with anti-human type VII collagen antibody stained the dermal-epidermal junction in control mice, but did not stain the skin of Col7a1 null mice. Collectively, the DEB mice recapitulate the clinical, genetic, immunohistochemical and ultrastructural characteristics of recessive DEB in humans. These mice provide an animal model to study the pathomechanisms of DEB and serve as a system to test therapeutic approaches, including gene replacement, towards the cure of this devastating skin disease.
Animals↗
Identification of the cyclosporin-binding site in P-glycoprotein.
The binding site of cyclosporin A to P-glycoprotein was characterized by using a multidrug-resistant Chinese hamster ovary cell line. P-glycoprotein photolabeled with diazirine-cyclosporin A analogue was purified by a two-step process involving continuous elution electrophoresis followed by wheat germ agglutinin-agarose precipitation. The cyclosporin A covalently bound to P-glycoprotein and to subsequent proteolytic fragments was detected by Western blot analysis using a monoclonal antibody against cyclosporin A. Proteolytic digestion of purified P-glycoprotein by V8 generated a major fragment of 15 kDa photolabeled by cyclosporin A, while proteolysis of P-glycoprotein photolabeled by [125I]-iodoaryl azidoprazosin generated a major fragment of 7 kDa. Limited proteolysis of cyclosporin A-photolabeled P-glycoprotein with trypsin indicated that the major binding site for cyclosporin A was in the C-terminal half of the protein. This cyclosporin A binding site was further characterized with chemical agents (N-chlorosuccinimide, cyanogen bromide, and 2-nitro-5-thiocyanobenzoate). These three chemical agents established a proteolytic profile of P-glycoprotein for fragments photolabeled with cyclosporin A and for fragments that contained the C494 and C219 epitopes. The smallest fragments generated by these chemical agents include the transmembrane domains (TMs) 10, 11, and 12 of P-glycoprotein. When the fragments generated by these chemical agents are aligned, the region that binds cyclosporin A is reduced to the 953-1007 residues. These combined results suggest that the major binding site of cyclosporin A occurs between the end of TM 11 and the end of TM 12.
ATP Binding Cassette Transporter, Subfamily B, Mem↗