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Biomedical subjects

R E Gay

Publications and source records attributed to R E Gay.

At least 127 records · Page 7Linked to original sources
PubMed1989

Immunohistologic demonstration of platelet-derived growth factor (PDGF) and sis-oncogene expression in scleroderma.

Although the pathogenesis and mechanisms responsible for excessive connective tissue deposition are not known, it has been thought that specific growth factors may have an effect on scar formation by increasing the fibroblast population and by affecting the amount and types of matrix synthesized. In this regard, we explored the appearance and localization of TGF alpha, TGF beta, PDGF, and sis-onc expression in situ. Sections of skin biopsies from eight scleroderma patients were investigated using specific antibodies to TGF alpha, TGF beta, human PDGF, and sis-onc products for immunohistochemistry. Most significantly, deposition of PDGF was detected in the endothelial lining of small capillaries in association with certain mononuclear cells of the perivascular infiltrates. In particular, strong labeling was observed in the cytoplasm of macrophages. Smooth muscle also appeared to be specifically labeled. Similarly, sis-onc product localized in the same areas. No significant staining was observed with antibodies to TGF alpha. TGF beta was found rather diffusely throughout the dermal connective tissue and was only occasionally observed in capillaries of lesions. We conclude that the PDGF may play an important role in the pathogenesis of scleroderma.

Humans↗
PubMed1989

Immunohistochemical localization of HTLV-I p19- and p24-related antigens in synovial joints of patients with rheumatoid arthritis.

In formalin-fixed, paraffin-embedded synovial tissues from patients with early proliferative rheumatoid arthritis (RA), immunoreactivity could be demonstrated utilizing monoclonal IgG antibodies reactive with the p19 and p24 protein of human T cell leukemia virus (HTLV-I). Additionally, surgical specimens of fresh unfixed synovial tissues from patients with RA also demonstrated immunoreactivity. At the light microscopic level, both HTLV-I antigens were detected in approximately 45% of the rheumatoid synovial tissues by the immunocolloidal gold method with silver enhancement (IGSS) and the avidin-biotin-complex technique (ABC), whereas six of eight of the frozen RA specimens stained positive by immunofluorescence. Patients whose synovial tissues were immunoreactive by immunofluorescence were seronegative to HTLV-I antigens as determined by ELISA and immunoblotting. Conversely, cases with osteoarthritis, juvenile rheumatoid arthritis, psoriatic arthritis, Dupuytren's contracture, and gangrene were shown to be nonreactive by immunohistochemistry. The results indicate that expression of antigens is related to or crossreactive with HTLV-I in synovial tissues from patients with rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1987

Humoral sensitivity to native collagen types I-VI in the arthritis of MRL/l mice.

The presence of immune reactivity to collagen in patients with rheumatoid arthritis as well as recent interest in the type II collagen-induced arthritis model have suggested a role for autoimmunity to collagen as a major disease mechanism. However, data concerning the occurrence of antibodies (AB) against the different types of collagen during a spontaneously occurring, histologically well-defined arthritis have been lacking. Sera from 48 MRL/l mice aged 5 to 25 weeks with spontaneously occurring hindlimb arthritis were obtained. Sera were tested for auto-AB against collagens utilizing highly purified native collage types I-VI. Significant levels of circulating AB against native collagen types I, III, and VI could not be detected in any age group. The greatest elevation of antibodies directed against type II collagen was found in 13- to 15-week-old mice. AB against type IV collagen were detected in slightly elevated levels with a maximum at 9-10 weeks. Most strikingly, AB against type V were markedly elevated after 19 weeks. The occurrence of high levels of AB against type V collagen, largely found in the pericellular matrix of smooth muscle cells, is associated with the late stage of disease characterized by histologically documented vasculitis. The results suggest that AB to collagen occur as a consequence of tissue destruction and that evidence for a pathogenetic role of AB in MRL/l arthritis is lacking.

Animals↗
PubMed1986

Characterization of the in vitro stromal microenvironment of human bone marrow.

Utilizing long-term in vitro culture techniques, we characterized the cellular composition and functional attributes of the human in vitro bone marrow stromal microenvironment. Morphologic, specific cytochemical and immunologic methods demonstrated that the marrow stromal adherent layer (AL) reached confluency at two to three weeks, and was comprised of 60%-70% fibroblastic cells, 10%-20% endothelial cells, 10%-20% monocyte/macrophages and 5%-10% fat-laden adherent cells. These proportions of cell types persisted for at least three months concomitant with proliferation of CFU-gm and BFU-e. In contrast, umbilical cord blood cells did not form a stromal AL despite persistence of hemopoietic progenitor cell proliferation. These findings provide a basis for improved understanding of cellular interactions regulating hemopoiesis.

Bone Marrow Cells↗
PubMed1986

The extracellular matrix in "sclerosing" follicular center cell lymphomas: an immunohistochemical and ultrastructural study.

"Sclerosis" is frequently seen in follicular center cell (FCC) lymphomas. The mechanism of its deposition, as well as its composition and significance, are unknown. Several clinical studies have suggested that the course of these lymphomas is more indolent than that of lymphomas of the same histologic type without sclerosis. Nine immunologically characterized cleaved FCC lymphomas with sclerosis and 14 reactive lymph nodes with follicular hyperplasia were investigated by special staining methods, electron microscopy, and immunohistochemical studies with antibodies to types I, III, IV, and V collagen, laminin, and fibronectin. The sclerotic tissue in FCC lymphomas stained uniformly with periodic acid-Schiff (PAS) and Masson's stain, with the patterns ranging from delicate filamentous strands to dense doubly refractile bands. Ultrastructurally, the bands of connective tissue were continuous with the adventitia of vessels and composed of varying amounts of banded collagen (types I and III) admixed with filamentous and flocculent material. In all cases the neoplastic lymphocytes were separated from the extra-cellular matrix by fibroblasts and myofibroblasts with long cell processes. Immunohistochemical studies demonstrated intense staining of sclerotic bands with antibodies to fibronectin and type I collagen and, usually, weaker marking with antibodies to types III and V collagen. No significant staining of sclerotic bands was found with antibodies to type IV collagen or with laminin. Weak pericellular staining for type V collagen was present in eight of nine lymphomas and half of the control lymph nodes. These studies suggest that the increased amounts of extracellular matrix in cleaved FCC lymphomas are produced primarily by fibroblasts and myofibroblasts and represent predominantly fibronectin and types I, III, and V collagen. The composition of the sclerotic areas of FCC lymphomas is similar immunohistochemically to that of the capsule and trabeculae of reactive lymph nodes, which are also intimately associated with fibroblasts and myofibroblasts.

Extracellular Matrix↗
PubMed1986

Localization of type V collagen with monoclonal antibodies in developing dental and peridental tissues of the rat and hamster.

The distribution of collagen type V in developing dental and peridental tissues was investigated with the indirect immunofluorescence technique using unfixed, frozen sections of jaws from 1-2 day old neonatal rats and hamsters. Immunostaining for type V collagens was found both intracellularly and extracellularly in dental tissues of mesenchymal origin. In non-dental tissues, weak immunostaining was observed in the mesenchymally derived stroma surrounding the developing molar tooth germs but was more pronounced in larger cells, probably young osteoblasts in close vicinity to alveolar bone, and in some cells within developing salivary glands. Decalcification revealed a strong immunostaining in the extracellular bone matrices. In the dental tissues, the mesenchymally derived cells of the papilla exhibited an intracellular staining for type V collagen. In odontoblasts, increased immunostaining over that of other pulpal cells was observed just prior to or coinciding with the onset of predentin secretion and reactivity remained high in fully differentiated odontoblasts. A weak staining was observed in predentin but only after the onset of mineralization. As was the case for bone, after demineralization the dentin matrix stained intensely for type V collagen. The results demonstrate that type V collagen is actively synthesized by mesenchymal cells of developing hard tissues and that this type of collagen is an intrinsic component of hard connective tissue matrices. The data suggest that in developing tooth germs type V collagen is not involved in the differentiation process of either odontoblasts or ameloblasts.

Animals↗
PubMed1985

Alteration of the connective tissue network of striated muscle in copper deficient rats.

The connective tissue network in striated muscle, consisting principally of collagen is arranged in a three dimensional network and is intimately associated with muscle function. Previous studies have shown that animals maintained on a copper-deficient diet undergo myocardial hypertrophy and exhibit cardiovascular lesions such as ventricular aneurysms that eventually rupture. A deficiency of copper in the diet is known to inhibit lysyl oxidase, a metalloenzyme requiring copper as a cofactor and which is also responsible for collagen and elastin crosslinking. Examination by scanning and transmission electron microscopy of skeletal and cardiac muscle from rats maintained on copper-deficient diets showed both gross and microscopic lesions to the connective tissue network. Immunohistochemical staining by light microscopy with antibodies against lysyl oxidase showed that the enzyme was equally present in both control and experimental animals. Fluorescent staining for antibodies against collagen types I and III showed similar results. From these studies we concluded that the collagen secreted during hypertrophy was not crosslinked by lysyl oxidase due to the absence of the copper cofactor. This resulted in the failure of the connective tissue network to transmit and distribute the increased force associated with myocardial hypertrophy and resulted in myocardial aneurysms.

Animals↗
PubMed1984

Rheumatoid myositis. Clinical and histologic features and possible pathogenesis.

Thirty-one patients with rheumatoid arthritis were consecutively studied for evidence of muscle involvement, using muscle biopsy and electromyography. The patients were initially separated into 4 clinical categories: inactive peripheral joint disease (6 patients); active peripheral joint disease (10 patients); systemic disease and a disproportionately elevated sedimentation rate for the degree of mild synovitis (SERD) (11 patients); or elevated creatinine phosphokinase level (4 patients). In addition to routine histology, muscle tissue was examined for de novo synthesis of IgM and IgM rheumatoid factor, and by indirect immunofluorescence for the presence of immunoglobulin and complement deposits. Our results indicate that: muscle fiber necrosis occurs frequently in patients with rheumatoid arthritis; rheumatoid myositis, defined as muscle fiber necrosis and mononuclear cell infiltration, is a distinct entity and occurs particularly in patients with SERD or an elevated creatinine phosphokinase level; and only muscle from patients with rheumatoid myositis exhibited de novo synthesis of rheumatoid factor and significant quantities of IgM, indicating that local immune events may be important in the pathogenesis of this entity.

Arthritis, Rheumatoid↗
PubMed1983

Histological and immunohistological identification of collagens in basement membranes of Schwann cells of neurofibromas.

The application of immunohistological techniques that use antibodies highly specific for collagen allows new comparative studies in the distribution and deposition of genetically distinct types of collagens in neurofibromas. The identification of collagen type IV in basement membranes is unique and marks particularly the sheaths or cytoplasma of proliferating Schwann cells. Cells with greater degrees of atypia show increased amounts of intracellular collagen in basement membranes by immunohistologic examination, which provides an additional diagnostic tool in dermatopathology.

Basement Membrane↗
PubMed1982

Changes in the distribution of fibronectin and collagen during development of the neonatal rat heart.

Specific antibodies to different types of collagen (I, III, IV and V) and fibronectin were used to investigate the formation of the collagenous connective tissue network in the neonatal rat heart. Immunofluorescence data showed that the staining pattern for fibronectin and Type III collagen was similar as were the patterns for Type I, IV and V collagens. These differences in the staining patterns correlated with previous studies on the development of the connective tissue network and indicated that Type III collagen was the major type of collagen associated with the myocytes. The results of this study showed that by 20 days post-partum the development of the connective tissue network was similar to the adult.

Age Factors↗
PubMed1982

Characteristics of bone marrow fibroblast colony-forming cells (CFU-F) and their progeny in patients with myeloproliferative disorders.

Chronic myeloproliferative disorders (MPD) are clonal diseases of the pluripotent hematopoietic stem cell frequently associated with myelofibrosis (MF). There is only indirect evidence indicating that the increased deposition of collagen in bone marrow matrix is a secondary phenomenon. A liquid culture system for cloning and growing bone marrow fibroblasts has permitted us to approach more directly the understanding of the pathogenesis of myelofibrosis by comparing the biophysical, growth, and functional characteristics of fibroblasts from normals, MPD patients without MF, and those with MF. In patients with MF, marrow fibroblast colony (CFU-F) formation could not be studied; fibroblasts were grown from marrow explants. CFU-E from normals and MPD patients exhibited similar cell density distribution and similar cell sedimentation rates. These similarities contrasted sharply with the differences seen when the erythroid and granulocyte-macrophage progenitors were studied by the same methods. There was a marked light density shift and a rapidly sedimenting shift of MPD hematopoietic colony-forming cells. Marrow fibroblasts from MPD patients with and without MF displayed the same in vitro growth characteristics as fibroblasts from normals. Both types of fibroblasts exhibited anchorage and serum dependence, and contact inhibition of growth. Marrow fibroblasts were also characterized for the presence and distribution of fibronectin and collagen types by immunofluorescent staining using monospecific antibodies. Extracellular matrix, membrane-, and cytoplasm-associated fibronectin, type I, type III, and type V collagen showed a similar staining pattern in both normal and myelofibrotic marrow fibroblasts. Plasminogen-dependent fibrinolytic activity elicited from normal and myelofibrotic marrow fibroblasts were equivalent. Chromosomal analysis of hematopoietic cells and marrow fibroblasts from Philadelphia chromosome positive chronic myelocytic leukemia patients with and without MF showed that the Philadelphia chromosome was present only in hematopoietic cells. The results of these studies taken together demonstrate that bone marrow collagen-producing cells from MPD patients with and without MF behave in vitro as do those from normals. These findings support the hypothesis that that the marrow fibrosis observed in patients with MPD results from a reactive process rather than from a primary disorder affecting the marrow collagen-producing cells.

Adult↗
PubMed1981

Collagen molecules comprised of alpha 1(V)-chains (B-chains): an apparent localization in the exocytoskeleton.

Antibodies specific for alpha 1(V) chains and native collagen molecules containing the alpha 1(V) chain have been used to study the localization of alpha 1(V)-containing molecules in differentiating hyaline cartilage. Immunofluorescence data show that the undifferentiated mesenchyme contains significant quantities of these molecules throughout the cell-rich tissue matrix. Examination of fully differentiated hyaline cartilage reveals a unique staining pattern wherein the immunofluorescent material is restricted to the pericellular matrix within the chondrocyte lacunae. We conclude from these data in conjunction with other evidence that the Type V collagens function as components of an exocytoskeleton for connective tissue cells.

Animals↗
PubMed1980

Collagen types synthesized in dermal fibroblast cultures from patients with early progressive systemic sclerosis.

Fibroblast cultures were established by explant culture from upper and lower dermis of 7 normal donors and 10 patients with early progressive systemic sclerosis (PSS). Antibodies against collagens containing the A and B chains, collagens which occur largely in vascular structures, were isolated and used for immunofluorescence studies. Cultures from lower PSS dermis accumulated significantly more of these collagens than fibroblast cultures from upper PSS dermis or cultures from upper or lower dermis of normal skin. These data indicate that the collagens containing the A and B chains in early PSS lesions are produced by cells of vascular origin and support the concept that alterations in vascular tissue play a prominent role in the pathogenesis of PSS.

Adult↗