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Biomedical subjects

G F Murphy

Publications and source records attributed to G F Murphy.

At least 91 records · Page 5Linked to original sources
PubMed1993

Development of pemphigus vulgaris-like lesions in severe combined immunodeficiency disease mice reconstituted with lymphocytes from patients.

Pemphigus vulgaris is an autoimmune blistering disease that is induced by binding of antibodies to a 130/85-kD protein complex on epidermal keratinocytes. An in vivo experimental model of this disease was developed by reconstituting severe combined immunodeficiency (SCID) mice with 1-10 x 10(7) PBL from patients with naturally occurring pemphigus vulgaris. Of 49 reconstituted mice, 34 (69%) produced human IgG levels of > 0.1 mg/ml. Circulating anti-pemphigus antibodies were found in 20 of the 34 successfully reconstituted mice; 44% of these animals had deposits of human IgG in their own skin after it was traumatized by either heat or cold. Spontaneous pemphigus vulgaris-like blisters associated with human IgG deposits were rarely found in mouse skin. By contrast, allogeneic human skin grafted to 10 to 12 mice before reconstitution with patients' PBL developed pemphigus vulgaris-like lesions containing human IgG deposits. These results demonstrate that SCID mice can serve as a model of an antibody-mediated human autoimmune skin disease.

Adult↗
PubMed1993

Regulation of extracellular matrix proteins and integrin cell substratum adhesion receptors on epithelium during cutaneous human wound healing in vivo.

Although changes in extracellular matrix proteins during wound healing have been well documented, little is known about the regulation of corresponding extracellular matrix adhesion receptors (integrins). To study this process in a human in vivo model, full thickness human skin grafts were transplanted onto severe combined immunodeficient mice and deep excisional wounds involving both the epidermal and dermal layers were then made. The changes in the expression of cell matrix proteins and epithelial integrins over time were analyzed with specific antibodies using immunohistochemistry. Wounding was associated with alterations in extracellular matrix proteins, namely, loss of laminin and type IV collagen in the region of the wound and expression of tenascin and fibronectin. Changes were also noted in the integrins on the migrating keratinocytes. There was marked up-regulation of the alpha v subunit and de novo expression of the fibronectin receptor (alpha 5 beta 1) during the stage of active migration (days 1 to 3 after wounding). In the later stages of wound healing, after epithelial integrity had been established, redistribution of the alpha 2, alpha 3, alpha 6, and beta 4 collagen/laminin-binding integrin subunits to suprabasal epidermal layers was noted. Thus, during cutaneous wound healing, keratinocytes up-regulate fibronectin/fibrinogen-binding integrins and redistribute collagen/laminin-binding integrins. This study demonstrates that the human skin/severe combined immunodeficient chimera provides a useful model to study events during human wound repair.

Animals↗
PubMed1993

Novel interactions between dermal dendrocytes and mast cells in human skin. Implications for hemostasis and matrix repair.

BACKGROUND: Dermal dendrocytes are a newly-recognized cell type in human skin. They express coagulation Factor XIIIa (FXIIIa), also known as fibrin stabilizing factor, and their number is increased in certain inflammatory dermatoses. Current dogma suggests that these recently described cells may represent a subset of antigen-presenting macrophages. The present study therefore was undertaken to examine further the phenotype and potential function of these novel cells. EXPERIMENTAL DESIGN: Conventional ultrastructure, single and dual label immunofluorescence and immunocytochemistry, confocal laser scanning microscopy, and immunoelectron microscopy were used to define structure and potential heterogeneity among dermal dendrocytes. Human neonatal foreskin organ culture exposed to mast cell secretagogues, inhibitors, and relevant recombinant cytokines (tumor necrosis factors alpha) was employed to gain insight into functional characteristics of FXIIIa expression. RESULTS: We found that dermal dendrocytes are phenotypically unique dermal cells, separate from conventional macrophages, with antigenic heterogeneity of FXIIIa and CD34 expression related to their microanatomical location in the dermis. Moreover, they express specialized membrane-matrix plaques that may stabilize their placement in various dermal strata. Finally, superficial subpopulations of dermal dendrocytes are closely-associated with mast cells and show enhanced FXIIIa expression in response to mast cell degranulation, an event that appears to result from liberation of mast cell tumor necrosis factor in the dendrocyte microenvironment. CONCLUSIONS: These new insights establish dermal dendrocytes as distinctive fixed skin cells with potential functional capacity for mast cell-dependent facilitation of fibrin cross-linking and matrix remodeling. These previously unrecognized phenotypic and functional characteristics of dermal dendrocytes therefore may be relevant to cellular interactions responsible for cutaneous wound healing and hemostasis.

Cell Communication↗
PubMed1993

Histologic, ultrastructural, and immunocytochemical features of the granulomas seen in a child with the syndrome of familial granulomatous arthritis, uveitis, and rash.

A family with a syndrome consisting of granulomatous arthritis, uveitis, and rash was first described in 1985. Another family with the same syndrome was described subsequently in 1990. The condition, in both families, is clinically different from sarcoidosis. To verify whether the granulomas in such patients also could be distinctive, we performed histologic, ultrastructural, and immunocytochemical studies on skin and synovial biopsy specimens from a child under our care who suffered from the same syndrome. The results indicated that the granulomas could not be distinguished from those seen in sarcoidosis either by light microscopy or by immunocytochemical studies. However, by electron microscopy, "wormlike" or "comma-shaped" bodies were noted within the cytoplasm of epithelioid cells. The significance of this observation is discussed.

Arthritis↗
PubMed1993

Growth and invasion of human melanomas in human skin grafted to immunodeficient mice.

An orthotopic model of human melanoma was developed in which malignant cells were injected into human skin grafted to nude and SCID mice. Melanoma cells proliferated and invaded the human skin grafts with characteristic patterns. Three of six melanomas grew as multiple nodules and infiltered the grafts without major architectural changes in the dermis, whereas the others invaded the dermis along collagen fibers with prominent endothelial vessels. By contrast, melanoma cells inoculated into mouse skin grew as diffusely expanding nodules that did not invade the murine dermis. In human skin grafts, human melanoma cells were angiogenic for human blood vessels, and murine vessels were only found at the periphery of grafts. Tumor cells invaded the human vessels, and four out of seven cell lines metastasized to lungs, suggesting that this model is useful to determine in vivo the interactions between normal and malignant human cells.

Animals↗
PubMed1992

Immunohistochemical and ultrastructural characterization of tonofilament and hemidesmosome abnormalities in a case of epidermolysis bullosa herpetiformis (Dowling-Meara).

BACKGROUND: A neonate with epidermolysis bullosa herpetiformis (EBH) (Dowling-Meara) had an undescribed ultrastructural and immunohistochemical abnormality. OBJECTIVE: The objective was to clarify the ultrastructural and immunohistochemical abnormalities in EBH to gain further insight into the pathogenesis of this disorder. METHODS: Tissue from the patient was studied with routine histochemistry, electron microscopy, and immunohistochemistry. RESULTS: Excessive clumping of tonofilaments on electron microscopic examination, anomalous hemidesmosomes, and immunohistochemical evidence of aberrant keratin expression by basal epidermal cells was found. CONCLUSION: This case of EBH provides further evidence for primary abnormalities involving cytoskeletal-membrane attachment plaque formation in this rare disorder.

Desmosomes↗
PubMed1992

Characterization of inflammatory infiltrates in male pattern alopecia: implications for pathogenesis.

Hair-bearing, transitional, and alopecic scalp from three males and one female with progressive pattern alopecia were examined. Ultrastructural studies disclosed measurable thickening of the follicular adventitial sheaths of transitional and alopecic zones compared with those in the non-alopecic zones. This finding was associated with mast cell degranulation and fibroblast activation within the fibrous sheaths. Immunohistochemically, control biopsies were devoid of follicular inflammation (n = 3), while transitional regions consistently showed the presence of activated T-cell infiltrates about the lower portions of follicular infundibula. These infiltrates were associated with the induction of class II antigens on the endothelial linings of venules within follicular adventitia and with apparent hyperplasia of follicular dendritic cells displaying the CD1 epitope. Inflammatory cells infiltrated the region of the follicular bulge, the putative source of stem cells in cycling follicles. The data suggest that progressive fibrosis of the perifollicular sheath occurs in lesions of pattern alopecia, and may begin with T-cell infiltration of follicular stem cell epithelium. Injury to follicular stem cell epithelium and/or thickening of adventitial sheaths may impair normal pilar cycling and result in hair loss.

Adult↗
PubMed1992

Role of adhesion molecules in cutaneous inflammation and neoplasia.

There is accumulating evidence that the expression of certain adhesion molecules has important consequences for understanding patterns of cell movement in normal and pathologically altered skin. This paper reviews recent work regarding the role of integrins and other adhesion molecules (ICAM-1, VCAM-1, PECAM-1, LECAM-1, and ELAM-1) in cutaneous inflammation and neoplasia, and presents a unifying hypothesis which outlines how sequential expression of cytokines and adhesion molecules in evolving inflammation may alter the nature of the cellular response.

Cell Adhesion Molecules↗
PubMed1992

Eccrine syringofibroadenoma (Mascaro): an ultrastructural study.

To confirm the eccrine acrosyringeal differentiation of eccrine syringofibroadenoma (ESFA) and to elucidate the histogenesis of its angiofibrotic stroma, a case of ESFA from a 45-year-old man was examined by light and electron microscopy. Histologically, the parenchyma featured anastomosing, slender epithelial cords containing small cuboidal cells and occasional duct-like structures. The stroma had increased numbers of mast cells, increased capillaries with swollen endothelial cells, and prominent fibrosis. Ultrastructurally, the following findings were characteristic of ESFA: a) abundant glycogen particles in epithelial cells, b) numerous intracytoplasmic and extracellular spaces lined with microvilli, c) intraepithelial duct formation, consisting of microvilli, vesicles, rod-shaped dense bodies, multivesicular dense bodies, and peripheral network of tonofilaments, and d) large numbers of mast cells, closely associated with fibroblasts, surrounding increased numbers of capillaries containing swollen endothelial cells. These ultrastructural features support the acrosyringeal differentiation of ESFA. We hypothesize that mast cell hyperplasia and degranulation may play an important role in the formation of the angiofibrotic stroma.

Adenofibroma↗
PubMed1991

Induction of local inflammation by recombinant human platelet factor 4 in the mouse.

Platelet factor 4 (PF-4) has been shown to be chemotactic for neutrophils and monocytes in vitro. To assess whether these observations have in vivo relevance, we tested the ability of recombinant human PF-4 (rPF-4) to induce acute and chronic dermal inflammation in the mouse. When injected as a single dose intradermally, rPF-4 induced an acute inflammatory response that peaked at 6 to 12 hr and which resolved by 36 hr. Injection of an equivalent amount of cytochrome c, buffer alone, or an amino-terminal PF-4 peptide failed to elicit a significant inflammatory response; however, the carboxy-terminal PF-4 peptide retained proinflammatory properties. The inflammatory infiltrate induced by a single injection of either rPF-4 or the 41 amino acid carboxy-terminal peptide was composed of neutrophils and smaller numbers of mononuclear cells. Repeated injection of rPF-4 resulted in nearly equal numbers of neutrophils and mononuclear cells. Moreover, marked dermal fibrosis developed after only 5 days of daily injection of rPF-4. Although relatively high concentrations of rPF-4 were required to elicit an inflammatory response, these concentrations may be locally attainable during platelet aggregation. Our findings thus support the hypothesis that PF-4 may contribute to the development of inflammatory responses at sites of platelet aggregation.

Animals↗
PubMed1991

Human dermal mast cells contain and release tumor necrosis factor alpha, which induces endothelial leukocyte adhesion molecule 1.

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that mediates endothelial leukocyte interactions by inducing expression of adhesion molecules. In this report, we demonstrate that human dermal mast cells contain sizeable stores of immunoreactive and biologically active TNF-alpha within granules, which can be released rapidly into the extracellular space upon degranulation. Among normal human dermal cells, mast cells are the predominant cell type that expresses both TNF-alpha protein and TNF-alpha mRNA. Moreover, induction of endothelial leukocyte adhesion molecule 1 expression is a direct consequence of release of mast cell-derived TNF-alpha. These findings establish a role for human mast cells as "gatekeepers" of the dermal microvasculature and indicate that mast cell products other than vasoactive amines influence endothelium in a proinflammatory fashion.

Cell Adhesion↗
PubMed1991

Pilot study of sandostatin (octreotide) therapy of refractory HIV-associated diarrhea.

Seventeen AIDS patients were enrolled in a prospective open-label dose-finding study of octreotide (Sandostatin) therapy for refractory diarrhea. Five were nonevaluable due to progression of AIDS symptomatology, and one was excluded because of lack of confirmation of HIV infection. Five of 11 evaluable patients responded to therapy (45%); two each at 50 micrograms and 100 micrograms, and one at 250 micrograms thrice daily doses. A sixth patient demonstrated a moderate reduction in stool volume at 250 micrograms thrice daily, which, although deemed clinically relevant, did not meet the criteria for response. On discontinuation of therapy, diarrhea recurred in all patients within 1-12 days, and responded to reinitiation of octreotide in those five patients who resumed treatment. Only one of the three patients with concurrent cryptosporidial infection responded to treatment. The drug was well tolerated, with mild symptomatology in three patients. Long-term treatment at a stable dose was effective in three of five treated patients for periods for seven months in one (moderate responder) and one year in two. One patient required dose increases to control symptoms, but after one year of treatment developed severe nausea following injections, which required dose cessation. One patient had partial control of his diarrhea for only three months despite two dose increases. These data suggest that octreotide may be of useful therapeutic value in HIV-associated diarrhea and that further studies are indicated.

Adult↗
PubMed1991

Identification of a novel high molecular weight protein preferentially expressed by sinusoidal endothelial cells in normal human tissues.

Mouse mAb MS-1, raised against human spleen, detects an endothelial cell antigen abundantly expressed by the sinusoidal endothelia of spleen, lymph node, liver, and adrenal cortex, but absent from nonsinusoidal continuous endothelia in these organs. Immunoelectron microscopy of splenic tissue demonstrates that the MS-1 antigen is predominantly deposited at zones of intercellular contact between adjacent sinusoidal endothelial cells. mAb MS-1 also reacts with a variable proportion of high endothelial venules in tonsil, but not in other lymphoid tissues, and with an interstitial dendritic cell population most abundant in placenta. mAb MS-1 does not react with cultured resting or mediator- activated human umbilical vein endothelial cells, dermal fibroblasts, peripheral blood mononuclear cells, or the cell lines U937, HL-60, K562 or Mo7E; it does react with the primitive myeloid cell line KG-1. mAb MS-1 immunoprecipitates a major protein of 215 kD and minor proteins of 320 and 120 kD from splenic extracts as analyzed by SDS-PAGE with reduction. These proteins are soluble in aqueous buffers. Immunoprecipitation from KG-1 cell lysates detects four proteins of 280, 300, 205, and 120 kD; the 300-, 205-, and 120-kD species, presumably corresponding to the 320-, 215-, and 120-kD species in spleen, respectively, are secreted into the media. Under nonreducing conditions, immunoprecipitates from KG-1 cell lysates or conditioned media contain one predominant 300-kD species; upon isolation and reduction, this 300-kD species separates into the previously observed 300-, 205-, and 120-kD species. Pulse-chase experiments and limited proteolysis peptide mapping suggest that the 280-kD species is a precursor of the mature 300-kD species which may be subsequently cleaved to yield the 205- and 120-kD species. Because of its size, solubility and expression pattern, the antigen recognized by mAb MS-1 is likely to be an extracellular matrix protein utilized by endothelial cells of contorted, large caliber, or leaky microvessels that lack a well-formed basement membrane.

Adrenal Cortex↗
PubMed1991

Extracellular localization of human connective tissue mast cell granule contents.

In early phases of cutaneous inflammation, connective tissue mast cell degranulation is associated with apparent secretion and externalization of immunoreactive chymotryptic serine proteinase. To determine whether this event is associated with structural evidence of granule externalization, we studied the sequential evolution of IgE-mediated hypersensitivity in vivo, as well as mast cell degranulation provoked by a variety of stimuli in cultured explants of human skin. By 1 min after intradermal antigen challenge with ragweed extract, mast cell degranulation was associated with apparent extrusion of intragranule constituents into the pericellular connective tissue. Similar features typified cultured skin explants exposed for 45 min to anti-IgE and other mast cell secretagogues (morphine sulfate, calcium ionophore A23187, compound 48/80, and substance P). Once externalized, granule constituents could be identified within the dermal matrix by their rounded contour and structural similarity to solubilized granule matrices remaining within actively secreting cells. These data indicate that externalization of connective tissue mast cell granule contents occurs early after secretagogue exposure, potentially accounting for infrequent documentation of this event in naturally occurring dermatoses. The ability to recognize externalized granule products at a morphologic level should facilitate the understanding of interactions between mast cell-derived mediators and target structures of the dermal microvasculature.

Adult↗
PubMed1991

Cytotoxic folliculitis in GvHD. Evidence of follicular stem cell injury and recovery.

Recent observations indicate that stem cells of the murine hair follicle exist exclusively as a subpopulation of relatively undifferentiated outer root sheath cells located in the bulge region at the mid-portion of the follicle. Because it has been hypothesized that stem cells of interfollicular epidermis may represent targets of cytotoxic responses in acute graft-versus-host disease (AGVHD), we studied murine AGVHD and observed sequential skin biopsies for the presence and evolutionary pattern of follicular injury. 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 in skin of AGVHD, which peaked three weeks post-transplant. In the B10.D2- greater than DBA/2 strain combination, CD4+ effector cells, and to a lesser extent, CD8+ cells, mediated disease, which peaked during the fourth week post-transplant. Analysis of skin from both strain/effector cell combinations revealed follicular infiltrates preferentially involving follicular stem cell (FSC) regions (bulge) of anagen follicles between the second and third weeks post-transplant. These infiltrates often preceded infiltration of adjacent interfollicular epidermis and were associated with follicular involution to telogen (resting) phase. By the fourth week post-transplant, greater than 50% of follicles were in telogen phase and residual inflammation was minimal. This provided a unique opportunity to observe follicular recovery from telogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Chronic ciclosporin nephrotoxicity: a rabbit model.

Ciclosporin (CsA) was administered intravenously for 30 days to New Zealand white rabbits at the following doses: group A, 2.5 mg/kg/day; group B, 5.0 mg/kg/day; group C, 10 mg/kg/day; group D, saline control; group E, vehicle (cremophor-EL) control. Creatinine clearance was significantly reduced (p less than 0.05) at time of sacrifice in group C as compared to controls. There were no apparent differences among the five groups with respect to body weight gain or blood pressure. Morphologically, there were marked changes in the cytoarchitecture of the kidneys from all groups of animals treated with CsA. At the light microscopic level, in contrast to controls, there was the presence of leukocyte infiltration, tubular atrophy, interstitial fibrosis, and arteriolopathy. At the ultrastructural level, numerous vacuoles, lysosomal-like structures, and loss of cellular integrity were seen in the proximal and distal tubules, as well as interstitial fibrosis in the form of numerous collagen fibers. No changes in the glomeruli were seen in any of the CsA-treated groups. These findings are consistent with chronic CsA nephrotoxicity similar to that seen in man.

Animals↗
PubMed1991

MS-1 sinusoidal endothelial antigen is expressed by factor XIIIa+, HLA-DR+ dermal perivascular dendritic cells.

We have recently described a monoclonal antibody, termed MS-1, which reacts with sinusoidal endothelium as well as interstitial cells in a variety of nonlymphoid organs. In this report, we characterize the phenotypes of MS-1-positive cells in normal human skin. Double immunohistochemical and immunofluorescence labeling techniques demonstrate that MS-1 antibody identifies two cell types in human dermis: the first represented by weakly reactive lymphatic endothelial cells; and the second comprised of strongly reactive, highly dendritic perivascular cells which constitutively express both HLA-DR and factor XIIIa. These MS-1-positive dendritic interstitial cells are ultrastructurally distinctive, separate from mast cells, phagocytic macrophages, pericytes, blood vascular endothelial cells, and fibroblasts. MS-1-positive cells express this protein in discrete cytoplasmic compartments, and possibly as small plasma membrane-associated regions. The phenotype, dendritic morphology, and perivascular localization of MS-1-positive cells suggest that MS-1 antibody recognizes an epitope expressed by cells previously referred to as dermal perivascular dendritic cells or dermal dendrocytes. We have proposed that MS-1 protein may serve as an anchoring molecule for endothelial cells in sinusoidal spaces in the absence of well-formed basement membranes. MS-1 may similarly function to maintain the spatial relationship of dermal perivascular dendritic cells with the microvasculature.

Antigen-Presenting Cells↗