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Biomedical subjects

G Gabbiani

Publications and source records attributed to G Gabbiani.

At least 253 records · Page 14Linked to original sources
PubMed1977

Binding of anti-actin autoantibodies to platelets.

Normal platelets incubated with anti-actin autoantibodies (AAA) (from the serum of patients with chronic aggressive hepatitis) do not show binding of these antibodies as seen by indirect immunofluorescence. AAA serum does not inhibit thrombin-induced clot retraction, despite the binding of the antibodies to platelets in the clot. Similarly, AAA serum does not affect "reversible" or "irreversible" aggregation (induced by ADP, collagen or epinephrine), despite the binding of the antibodies to platelet actin under such circumstances. AAA also bind to platelets when aggregation is inhibited by EDTA. The incubation of "reversibly" aggregated platelet with AAA results in a small but definite binding of AAA to platelets. These findings suggest that during "irreversible" and/or "reversible" aggregation, changes take place at the surface of platelets which expose the antigen at the surface of the cell.

Actins↗
PubMed1977

Cellular distribution of sarcoplasmic calcium-binding proteins by immunofluorescence.

Specific antibodies against carp paravalbumin, crayfish calcium binding protein and crayfish arginine kinase were used for indirect immunofluorescence localization of the respective proteins. Simultaneous staining of the same muscle sections with human serum containing anti-actin autoantibodies served as a probe to identify the isotropic band. Parvalbumin appears to be evenly distributed in carp white muscle. The crayfish calcium binding protein however shows a distinct localization, in the isotropic band, coincident with the actin staining. Arginine kinase, which has the same molecular weight and is extractible in the same way as the calcium binding protein does not show this distinct localization, but is evenly present in crayfish tail muscle, similarly to parvalbumin. The possible meaning of the different distribution of the two calcium binding proteins is discussed.

Animals↗
PubMed1977

Collagen of Dupuytren's disease.

1. In contrast to collagen from the aponeurosis of normal adult subjects, the nodules, contractures and apparently unaffected aponeurosis from patients with Dupuytren's disease contained substantial amounts of type III collagen. 2. The presence of type III collagen supports the previous proposal that the initial response to injury is the synthesis of an increased proportion of this form of collagen. The increased amounts in the apparently unaffected aponeurosis indicate the disease is not strictly focal but more systemic than is usually considered.

Collagen↗
PubMed1977

Smooth muscle antibody in Burkitt's lymphoma and in nasopharyngeal carcinoma.

Smooth muscle antibodies (SMA) with specificity for actin, were found with a higher frequency in sera from Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC) patients than in sera from matched controls. No correlation could be found between SMA and anti-Epstein-Barr virus (EBV) antibody titres. There was no parallelism, in individual sera, between the finding of SMA and the occurrence of cold lymphocytotoxins, aother antibody activity found with an abnormally high frequency among BL and NPC patients. The reason why actin, a weak antigen in experimental animals, may become immunogenic in humans remains unexplained.

Actins↗
PubMed1977

[The contractile filament system of carcinoma cells. Immunofluorescent and electron microscopic study].

Recent research has shown that the cytoplasm of several varieties of non muscular cells contains contractile proteins similar to those of striated muscle (actin and myosin, with the control complex of troponin and tropomyosin). Using indirect immunofluorescent staining with specific antisera, the authors demonstrate that the cytoplasm of the cells of oral squamous cell carcinoma contains actin, myosin and actinin (tropomyosin seems to be lacking). They have found these contractile proteins inconstantly in various precarcinomatous states, but never in normal epithelium, except in a few basal cells. In electronic microscopy, these contractile proteins correspond to a network of microfilaments of 40-80 A, more rarely 100-120 A, Clearly different from tonofilaments, located mainly in the peripheral part of the cytoplasm, just under the plasmalemmal membrane. It is tempting to speculate that the occurence of a contractile filamentous apparatus in the cells of oral carcinomas--already described in skin and mammal gland carcinomas--allows to these cells amoeboid movements and active migration, which might to some extent explain their tendency to invade surrounding tissues and to produce metastasis.

Actinin↗
PubMed1977

Morphological functional changes of aortic endothelium during different types of hypertension.

In rats, ligature of the aorta between the renal arteries produces hypertension which in the early phase (6-7 days) is associated with elevated plasma renin content, and later (40 days) is associated with low plasma renin. During the early phase, the endothelium of the aorta shows elevated permeability to HRP, endothelial cells are hypertrophic and contain bundles of actin microfilaments. During the late phase, permeability to HRP is normal, the endothelial cells are flat and do not contain bundles of microfilaments. Probably the endothelial cells of aorta react in different ways to various hypertensive stimuli and/or adapt to high levels of blood pressure.

Animals↗
PubMed1977

Fixation of human anti-actin autoantibodies on skeletal muscle fibres.

Sera from five patients with chronic aggressive hepatitis containing smooth muscle autoantibodies were tested by means of indirect immunofluorescence for their binding to isolated rabbit skeletal muscle myofibrils. In all cases, the immunofluorescent staining was sharply localized to I bands. After incubation of these sera with skeletal muscle troponin-torpomyosin complex, purified troponin or purified tropomyosin, no changes in immunofluorescent staining of myofibrils were noted. However, the staining was abolished after incubation of the sera with skeletal muscle actin. In double immunodiffusion experiments, a single precipitation line was obtained after diffusion of the sera against crude or purified actin. It is concluded that, at least for the sera examined, smooth muscle autoantibodies are anti-actin autoantibodies. The high titre of such autoantibodies and their availability in clinical immunology laboratories make them a useful tool to study actin distribution in muscular and non-muscular cells.

Actins↗
PubMed1976

Collagen and myofibroblasts of granulation tissue. A chemical, ultrastructural and immunologic study.

In granulation tissue produced in the rat by subcutaneous injection of turpentine oil or polyvynile sponge implantation, the great majority of fibroblasts (myofibroblasts) possess a contractile apparatus which makes them similar to smooth-muscle cells. Chemical analysis shows that these granulation tissues contain a high proportion of Type III collagen, a genetically distinct collagen normally associated with embryonic dermal tissue. Type III collagen may persist up to 9 months after sponge implantation and myofibroblasts are seen in granulation tissue by means of electron microscopy and immunofluorescence. When granulation tissue is resorbed 50 days after turpentine oil injection, myofibroblasts disappear and the dermis contains Type I collagen. The concurrent presence of myofibroblasts and Type III collagen suggests that myofibroblasts, in addition to their contractile activity, synthetize, at least in part, type III collagen.

Animals↗
PubMed1976

Contractile events during inflammation.

Contractile events during wound healing. During granulation tissue contraction, fibroblasts develop characteristics typical of smooth muscle; (1) they contain an extensive cytoplasmic fibrillar system, (2) they show immunofluorescent labeling of anti-actin antibodies, (3) there are cell and cell to stroma attachments, (4) strips of granulation tissue, when tested pharmacologically in vitro, behave similarly to smooth muscle. These data support the view that under certain conditions, fibroblasts can differentiate into a cell type structurally and functionally similar to smooth muscle and this cell, the 'myofibroblast', plays an important role in connective tissue contraction. During epithelialization, epidermal cells develop an extensive cytoplasmic contractile apparatus which has morphological and immunological characteristics similar to those of myofibroblasts. Such apparatus disappears as soon as epithelialization is completed. It is proposed that such a contractile apparatus plays a role in cell motility enabeling individual cells to rearrange themselves in an appropriate pattern. In conclusion, significant amounts of contractile proteins may be synthetized by fibroblasts and epithelial cells during wound healing and may play an important role in this process.

Actins↗
PubMed1976

In vivo induction of tight junction proliferation in rat liver.

The chronic administration of phalloidin induces an extensive development of tight junctions between rat hepatocytes. The junctional strands lose their predominantly parallel orientation with respect to the canalicular lumen and extend abluminally in irregular patterns which cover large membrane areas at considerable distance from the bile canaliculi. These changes indicate both proliferation and provide further evidence that these junctions are not permanent differentiations of the cell membrane.

Animals↗
PubMed1976

Contractile proteins in human cancer cells. Immunofluorescent and electron microscopic study.

The presence of contractile proteins in human cancer cells has been studied by means of: a) immunofluorescent staining using specific antibodies, and b) electron microscopy in order to detect the presence of cytoplasmic filaments. The tissues examined were: normal human skin, basal cell carcinoma of the skin, squamous cell carcinomas (of skin, oral cavity, and larynx), normal nonlactating mammary gland, and infiltrating mammary carcinoma with or without fibrosis. Normal tissues were negative after immunnoflurosescent staining of contractile proteins and contained no or minimal amounts of microfilaments as judged by electron microscopy. Tumor cells were strongly positive after immunoflouorescent staining for actin, myosin, light and heavy meromyosin but were negative for tropomyosin. Moreover, they contained prominent microfilaments (40 to 80 A in diameter) with some filaments (100 to 120 A in diameter) scattered in between. It appears that malignant cells contain an increased amount of contractile proteins, organized in the form of a filamentous apparatus, when compared to their normal counterparts. The study of the presence of contractile proteins in tumor cells may be of potential importance in evaluating malignant growth.

Breast Neoplasms↗
PubMed1975

Increase of contractile proteins in human cancer cells.

Human cells from skin and mammary-gland carcinomas show strong immunofluorescent staining with specific antibodies against smooth-muscle actin, myosin heavy meromyosin and light meromyosin, and contain numerous microfilaments as seen by electron microscopy. This increase in the amount of contractile proteins distinguishes cancer cells from the cells of normal tissues.

Actins↗