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Biomedical subjects

G F Murphy

Publications and source records attributed to G F Murphy.

At least 109 records · Page 6Linked to original sources
PubMed1991

Early cellular events in evolving cutaneous delayed hypersensitivity in humans.

The delayed-type hypersensitivity reaction (DHR) in human skin is prototypic for many inflammatory dermatoses. However the cellular events that precede gross lesion formation are unknown. In this study, inflammatory cell populations and adhesion molecule expression in early phases of DHR elicited by 2,4-dinitrochlorobenzene were evaluated. The first discernible event (at 1 hour) was mast cell degranulation, followed by induction of endothelial leukocyte adhesion molecule (ELAM-1) expression on dermal postcapillary venules at 2 hours. Endothelial leukocyte adhesion molecule expression peaked at 24 hours and declined by 48 hours. In contrast, endothelial expression of intercellular adhesion molecule-1 (ICAM-1) remained at constitutive levels. Intrafollicular T-cell migration occurred independent of ICAM-1 expression and commenced as early as 4 hours after challenge. Mature, activated CD4-positive lymphocytes that expressed a helper-inducer/memory phenotype predominated in early lesions. These results demonstrate in vivo that mast cell degranulation, ELAM-1 expression, and memory T-cell-follicular interactions are key events in subclinical evolutionary stages of cutaneous DHR.

Adult↗
PubMed1991

Decreased hospitalization and increased height velocity in focal segmental glomerulosclerosis responsive to ciclosporin A.

Eleven pediatric patients with nephrosis and focal segmental glomerulosclerosis were treated with long-term (8-38 months) ciclosporin A in combination with steroids. All had abnormal height-velocity curves and multiple hospitalizations for complications of nephrosis. Eight patients attained remission with a dramatic improvement in growth and decrease in necessity for hospitalization for therapy of nephrosis complications, while maintaining adequate renal function. Three nonresponders developed end-stage renal disease. Long-term ciclosporin A therapy may be of benefit in steroid-resistant nephrosis in childhood.

Child↗
PubMed1991

Characterization of target injury of murine acute graft-versus-host disease directed to multiple minor histocompatibility antigens elicited by either CD4+ or CD8+ effector cells.

The precise identity of effector mononuclear cells capable of eliciting acute graft-versus-host disease (AGVHD) is controversial. In this study, highly purified subsets of donor T cells were used to produce AGVHD to multiple minor histocompatibility (H) antigens in two strain combinations of mice matched for the major histocompatibility complex (MHC). In the C3H.SW- greater than B6 strain combination, only CD8+ effector cells produced histologic evidence of AGVHD in skin and liver, which peaked 3 weeks after transplant. In the B10.D2- greater than DBA/2 strain combination, CD4+ effector cells, and to a lesser extent, CD8+ cells, mediated disease in skin, liver, and intestine, which peaked during the fourth week after transplant. Analysis of skin and liver from both combinations showed target cell injury that was phenotypically similar and resembled that previously described in human disease in other studies. In addition, prominent epithelial injury also was detected in oropharyngeal mucosa, esophagus, hepatobiliary ducts, and seminal vesicle in both transplant settings. These findings indicate that functionally different subsets of donor T cells may be capable of initiating common pathways of cellular injury in selected target sites in AGVHD, and have potential implications for strategies that seek to ablate disease development by manipulation of donor marrow before transplantation.

Acute Disease↗
PubMed1991

Role of laminin in localization of human dermal mast cells.

Human connective tissue type mast cells (CTMC) are frequently located in close proximity to microvascular and neural basement membranes (BM). We have explored the interaction between human dermal connective tissue-type (chymase positive) mast cells and laminin, a component of BM. In this report, we document that normal CTMC express laminin receptors and are intimately associated with laminin of BM in vivo and pericellular laminin complexes in vitro. Upon degranulation in vitro, CTMC-laminin complexes dissociate and CTMC do not adhere to laminin substrates. In cutaneous mastocytosis/urticaria pigmentosa, CTMC do not express laminin receptors detectable by immunohistochemistry, and are frequently not in close association with laminin of vascular BM. These same features could be induced by degranulation of normal mast cells in organ culture. These findings indicate that CTMC-laminin interactions may be important determinants of mast cell localization in tissue compartments.

Basement Membrane↗
PubMed1991

Hairless micropig skin. A novel model for studies of cutaneous biology.

Reported here is the structural and immunohistochemical similarities between the Yucatan hairless micropig (HMP) skin and that of humans. Hairless micropig skin surface was composed of complex intersecting furrows that created geometric patterns remarkably similar to human skin surface glyphics. The dermal--epidermal interface consisted of undulant downgrowths that interdigitated with dermal papillae. Hairless micropig epidermis contained two morphologically distinct populations of basal keratinocytes (serrated and nonserrated). Similar heterogeneity has been seen only in human epidermis and primate palmar epidermis. Immunohistochemistry revealed that the HMP epidermis is reactive with monoclonal and polyclonal antisera to keratin proteins. Melanocytes reactive with antisera to S-100 protein, as in human skin, also were observed in HMP epidermis. Organization of dermal extracellular matrix, including collagen and elastic fibers, and the organization and reactivity of the microvasculature with antisera to factor VIII, were consistent with human skin. The costicosteroid-induced atrophy and subsequent rebound phenomenon after withdrawal of steroid observed in HMP skin was similar with that observed in humans. It is concluded that HMP skin approximates human skin significantly more precisely than most existing species and is an excellent model for studies of cutaneous physiology and pharmacology.

Animals↗
PubMed1990

Regressing atypical histiocytosis. Aberrant prothymocyte differentiation, T-cell receptor gene rearrangements, and nodal involvement.

Two cases of regressing atypical histiocytosis were studied. New findings reported include the presence of CD1 epitope on large atypical histiocytoid cells and apparent early lymph node involvement. Because regressing atypical histiocytosis may demonstrate aberrant thymic differentiation antigen expression and T-cell receptor gene rearrangements, initial lymph node involvement, and eventuation in conventional lymphoma in some cases, the alternative term regressing-phase anaplastic lymphoma is proposed as a more accurate designation for this entity.

Aged↗
PubMed1990

Nuclear shape analysis for assessment of prognosis in renal cell carcinoma.

Clinically localized renal cell carcinoma is cured by radical nephrectomy in 47% [stage T3a (II)] to 65% [stage T1, T2 (I)] of the patients. Local recurrence and metastatic disease probably result from undetectable microscopic metastases present at operation. Chemotherapy and immunotherapy may improve cure rates if administered adjuvantly. The outcome of individual patients who share surgical stage cannot be predicted reliably by tumor histology, pathological and/or nuclear deoxyribonucleic acid analysis. Two groups of 10 patients with clinically localized renal cell carcinoma were similar by sex distribution (5 men and 5 women), surgical stage (stages T1 in 1, T2 in 6 and T3a in 3 patients) and age (54.3 +/- 15.2 standard deviation versus 55.8 +/- 8.7 years). Group 1 had no recurrences with a minimum followup of 5 years and a mean followup of 10 years. Group 2 died of metastatic renal cell carcinoma after a mean of 5 years. All neoplastic areas of each paraffin-embedded operative specimen were randomly sampled and the nuclear perimeter of 150 cancerous cells was digitized. There were 25 shape descriptors calculated for each nucleus. All shape descriptors for each patient were described by 19 statistical tests. Nuclear perimeter and area as well as mean nuclear roundness factor failed to separate the 2 groups. Range median quartiles of ellipticities by Fourier analysis, coefficients of variation of chain code minimums and relative means of largest 10 convexity values produced greatest separation (Mann-Whitney-Wilcoxon test p less than 0.001, and variance normalized difference 3.21, 3.29 and 2.83, respectively). These descriptors normalized and summed provided near perfect separation (Mann-Whitney-Wilcoxon test p less than 0.001 and variance normalized difference 3.59). We developed a quantitative nuclear morphometric analysis system that permitted the correct assignment of outcome in 19 of 20 patients. Accurate prediction of prognosis in patients with clinically localized renal cell carcinoma by nuclear shape analysis may allow for selection of patients for adjuvant therapy who have clinically undetectable metastatic disease.

Carcinoma, Renal Cell↗
PubMed1990

Substance P induces the expression of an endothelial-leukocyte adhesion molecule by microvascular endothelium.

Leukocyte trafficking in normal and diseased skin appears to be initially governed by endothelial surface glycoproteins that promote adhesive interactions with circulating leukocytes. In a separate study, we have demonstrated that one of these glycoproteins, endothelial-leukocyte adhesion molecule-1 (ELAM-1), is rapidly induced on postcapillary dermal venules as a direct consequence of experimentally-elicited degranulation of adjacent mast cells (Proc Natl Acad Sci USA 86:8972-8976, 1989). A principle endogenous mediator of mast cell degranulation is the neuropeptide substance P. In this study, we exposed organ cultures of neonatal human foreskins for 45 min to substance P or to a substance P analogue (D-pro4, D-trp7,9)SP(4-11) that binds to the identical mast cell surface receptor but which does not provoke histamine release. Dermal mast cells were uniformly degranulated only in explants exposed to substance P, as judged by ultrastructural analysis. After subsequent culture in medium alone for 6 h, superficial venules of explants exposed to substance P showed evidence of ELAM-1 induction, as documented histochemically using H4/18 monoclonal antibody. ELAM-1 was not induced by substance P analogue. Furthermore, preincubation of explants with analogue or with the mast cell inhibitor, cromolyn sodium, abrogated the ability of substance P to induce ELAM-1. From these results we suggest that substance P endogenously released by dermal nerve fibers upon physiologic or electrical stimulation may be important in the regulation of endothelial-leukocyte interactions in vivo. This concept provides further evidence for a neurogenic and psychogenic modulation of the immune response, and may be relevant to the course of naturally occurring dermatoses (e.g., psoriasis) that are commonly exacerbated by emotional stress.

Cell Adhesion Molecules↗
PubMed1990

Phenotypes and interactions of human melanocytes and keratinocytes in an epidermal reconstruction model.

The morphologic and antigenic phenotype of normal human melanocytes and keratinocytes was investigated in monolayer and 3-dimensional cultures in an effort to develop an epidermal model that resembles the normal human epidermis. When cultured for several passages in optimal growth medium, pure cultures of either cell type could be established as demonstrated by light and electron microscopy and with monoclonal antibodies defining melanocyte- and keratinocyte-associated antigens. Three-dimensional growth of keratinocytes on polycarbonate filters was induced by increasing calcium concentrations in the culture medium and exposing cultures to air. After 30 to 35 days incubation, the 3-dimensional keratinocyte cultures reached a total of 12 to 25 layers and keratinocytes of various stages of differentiation formed three morphologically and antigenically different strata. The basal layer of these constructs consisted of ovoid cells with desmosomes and hemidesmosome-like structures. These cells expressed low molecular weight cytokeratins similar to basal cells in situ. The intermediate layer, representing the stratum spinosum in situ, contained flat cells with keratohyaline granules and many desmosomes. These cells expressed gp 80 kilodaltons, gp 40 to 50 kilodaltons, involucrin, and filaggrin. The upper layer, the stratum corneum equivalent, contained large, flattened cells with keratohyaline granules. The majority of these cells were anucleate. When melanocytes were cocultured with keratinocytes in monolayer or in epidermal reconstructs, they assumed a multidendritic morphology and donated pigment to surrounding keratinocytes. The majority of pigmented cells localized singly within the basal layer of the reconstructs and their dendrites were intimately associated with keratinocyte plasma membranes. Pigment donation to keratinocytes appeared to occur through the uptake of melanosome-containing dendrite fragments and phagocytosis of individual melanosomes by keratinocytes. It is hypothesized that keratinocytes produce unique microenvironmental factors that regulate the melanocytic phenotype.

Cell Communication↗
PubMed1990

Partial dermal regeneration is induced by biodegradable collagen-glycosaminoglycan grafts.

We have sequentially documented the early morphologic events that result in partial regeneration of the adult guinea pig dermis. This phenomenon occurs when a full-thickness skin wound is grafted with a highly specific collagen-glycosaminoglycan (CG) copolymer which has been seeded with autologous dermal and epidermis cells (Yannas IV, Lee E, Orgill DP, Skrabut EM, Murphy GF, Proc Natl Acad Sci USA 86:933-937, 1989). By day 7, ultrastructural analysis disclosed highly organized associations between mononuclear cells and CG fibers involving prominent extension of pseudopod-like processes toward the fiber surface. Spatial organization of cells was not evident in ungrafted wounds. By day 10, more than 50% of the CG grafts had been degraded and extensive neovascularization was observed in various stages of formation. By day 14, dermal fibroblasts in the graft site demonstrated random alignment of long axes, and a minor fraction (less than 10%) exhibited features of myofibroblasts. A majority (greater than 50%) of dermal fibroblasts in ungrafted wounds were identified as myofibroblasts at this time, and their axes were regularly aligned in parallel with the overlying epidermal layer. Scattered CG copolymer fragments were engulfed by macrophages by day 14, and complete dissolution occurred by day 21. Dermal blood vessels formed a discrete, subepidermal plexus oriented parallel to the epidermal plane by days 14 to 17 in grafted wound beds but not in ungrafted ones. Progressive, randomly oriented collagen deposition occurred at graft sites during the 1st year, whereas collagen fibers in ungrafted wounds were aligned in a horizontal plane atypical of a forming scar. By 1 year, the graft sites resembled normal dermis, with well-defined dermal papillae, normal anastomosing superficial vasculature, nerve fibers, and random collagen fiber morphology. Wound sites at this juncture resembled a mature scar, with a flattened dermal-epidermal interface; rare and disorganized vessels and nerves; and collagen fibers parallel to the epidermis. This investigation demonstrates the critical importance of highly specific extracellular matrix in induction of dermal morphogenesis.

Animals↗
PubMed1990

Clinical and ultrastructural studies of Romberg's hemifacial atrophy.

Romberg's disease is an uncommon and poorly understood condition manifested by progressive hemifacial atrophy of skin, soft tissue, and bone. In order to better define the natural history and anatomic variation of this disorder, we evaluated 41 patients by history, physical examination, and facial radiographs. Light microscopic studies were performed on tissue from 19 patients, and ultrastructural analysis was performed on specimens from 6 patients. The average age at inception of the disease was 8.8 years. Atrophy, within one or more trigeminal nerve dermatomes, progressed at a variable rate (mean period of active tissue dissolution = 8.9 +/- 6 years). In 26 patients with skeletal involvement, the mean age of onset was 5.4 years, versus 15.4 years for 15 patients without skeletal involvement, a statistically significant difference (p less than 0.01). However, there was no correlation between the severity of soft-tissue deformity and the age of onset. Electron microscopy demonstrated lymphocytic infiltrates in neurovascular bundles and abnormalities of vascular endothelium and basement membranes. We hypothesize that the pathogenesis of Romberg's disease involves chronic cell-mediated vascular injury and incomplete endothelial regeneration along branches of the trigeminal nerve (lymphocytic neurovasculitis).

Adult↗
PubMed1990

Characterization of cellular dermal infiltrates in human cutaneous mastocytosis.

Biopsies of lesional and nonlesional skin from 14 patients with localized cutaneous or associated systemic mastocytosis were examined by ultrastructural and immunohistochemical techniques. Mast cells within lesions of the dermis were highly variable between patients with regard to cell number and extent of degranulation, although lesional sites consistently contained more mast cells than did nonlesional sites. Two mast cell patterns were identified based upon granule morphology. In biopsies from 8 patients, the majority of granules contained electron-dense amorphous zones; crystalline lattices; and indistinct, incomplete solid scrolls forming parallel lamellae. In biopsies from 6 patients, in addition to these granules, there were also granules composed of electron-dense amorphous zones, reticulated matrices, and/or distinct scrolls with lucent cores interrupted by dense spheres. The granule morphology for the first group (N = 8) was identical with that seen in the preponderant type of skin mast cell of 6 normal control subjects, whereas the granule morphology of the second group (N = 6) displayed an abnormal ultrastructural phenotype for skin that included granule types normally found not only in skin but also in intestinal lamina propria and lung. For individual patients, the patterns of granule ultrastructure were consistent between clinically nonlesional and lesional skin. A minority of cells in both patient groups appeared primitive ultrastructurally, exhibiting rudimentary, Golgi-associated progranules; monocyte-like morphologic characteristics; and mitotic activity. Moreover, when mast cells in lesional skin were screened for a limited panel of surface antigens, they displayed common patterns of reactivity (M718+, HLA-DR/DQ+, CD4+), and in a selected case, immunoelectron microscopy confirmed the presence of these antigens on mast cell plasma membranes. Dermal mast cells from normal donors (N = 6) lack these epitopes. These observations suggest that infiltrates in cutaneous mastocytosis may exhibit phenotypic characteristics not only of cutaneous mast cells, but in some patients also of mucosal mast cells. In either circumstance, the mast cells may display antigenic determinants common to monocyte/macrophages. Concordance of granule phenotype between lesional and clinically uninvolved skin of individual patients furthers the notion that even localized mastocytosis reflects covertly defective systemic mast cell homeostasis.

Adult↗
PubMed1989

Degranulation of human mast cells induces an endothelial antigen central to leukocyte adhesion.

To understand better the role of mast cell secretory products in the genesis of inflammation, a system was developed for in vitro degranulation of human mast cells in skin organ cultures. Within 2 hr after morphine sulfate-induced degranulation, endothelial cells lining microvessels adjacent to affected mast cells expressed an activation antigen important for endothelial-leukocyte adhesion. Identical results were obtained when other mast cell secretagogues (anti-IgE, compound 48/80, and calcium ionophore A23187) were used. Induction of this antigen was abrogated by preincubation with cromolyn sodium, an inhibitor of mast cell secretion, and by antiserum to tumor necrosis factor alpha. These findings indicate that degranulation of mast cells activates dermal endothelium through tumor necrosis factor-dependent mechanisms. This event may be critical to the elicitation phase of cutaneous inflammation.

Adult↗
PubMed1989

Synthesis and characterization of a model extracellular matrix that induces partial regeneration of adult mammalian skin.

Regeneration of the dermis does not occur spontaneously in the adult mammal. The epidermis is regenerated spontaneously provided there is a dermal substrate over which it can migrate. Certain highly porous, crosslinked collagen-glycosaminoglycan copolymers have induced partial morphogenesis of skin when seeded with dermal and epidermal cells and then grafted on standard, full-thickness skin wounds in the adult guinea pig. A mature epidermis and a nearly physiological dermis, which lacked hair follicles but was demonstrably different from scar, were regenerated over areas as large as 16 cm2. These chemical analogs of extracellular matrices were morphogenetically active provided that the average pore diameter ranged between 20 and 125 microns, the resistance to degradation by collagenase exceeded a critical limit, and the density of autologous dermal and epidermal cells inoculated therein was greater than 5 x 10(4) cells per cm2 of wound area. Unseeded copolymers with physical structures that were within these limits delayed the onset of wound contraction by about 10 days but did not eventually prevent it. Seeded copolymers not only delayed contraction but eventually arrested and reversed it while new skin was being regenerated. The data identify a model extracellular matrix that acts as if it were an insoluble growth factor with narrowly specified physiochemical structure, functioning as a transient basal lamina during morphogenesis of skin.

Animals↗