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Biomedical subjects

J S Pedersen

Publications and source records attributed to J S Pedersen.

54 records · Page 3Linked to original sources
PubMed1985

Absence of autoimmune serological reactions in chronic non A, non B viral hepatitis.

In 18 cases of chronic liver disease due to non-A, non-B hepatitis virus(es) in which the diagnosis was established by transmission, including chimpanzee inoculation in nine, sera were tested for the autoantibodies characteristically associated with autoimmune chronic active hepatitis. The frequency of autoantibodies to nuclear, smooth muscle, cytofilament, mitochondrial and liver membrane antigens was low, being not greater than that recorded for a normal population, and the few positive reactions obtained were at very low titre. These findings suggest that among cases of 'HBsAg negative' chronic hepatitis, those due to NANB infection are distinguishable from those due to autoimmune chronic hepatitis by negative serological tests for autoantibodies.

Actins↗
PubMed1985

65-70 kD protein identified by immunoblotting as the presumptive gastric microsomal autoantigen in pernicious anaemia.

Sera from 20 of 24 patients with pernicious anaemia reacted by immunoblotting with a 65-70 kD protein in canine and rodent gastric mucosal cells enriched for 80-90% parietal cells, and in microsomal preparations derived from these cells. All 20 reactive sera were positive for parietal cell microsomal antibody demonstrated by immunofluorescence. Eighteen parietal cell microsomal antibody-positive sera from patients with unconfirmed pernicious anaemia also reacted with the same 65-70 kD protein. Serum reactivity with the same 65-70 kD protein was not seen with canine and rodent liver cells or with microsomal preparations derived from these cells. Sera from 10 patients with chronic active hepatitis, 10 with scleroderma and 10 with rheumatoid arthritis and 22 healthy persons did not react with the 65-70 kD protein. These results suggest that the 65-70 kD protein is probably the parietal cell microsomal autoantigen. A second antigen of 85-90 kD mol. wt. present only in canine gastric mucosal preparations also correlates with the presence of parietal cell microsomal antibody. However, the contribution of this second antigen to parietal cell microsomal antibody reactivity remains uncertain.

Anemia, Pernicious↗
PubMed1984

Vimentin organizing centre in cultured epithelial cells.

Perinuclear buttons were identified in cultured epithelial cell lines, with monoclonal antibodies to vimentin, following treatment with drugs which disrupt intermediate filaments. These buttons appeared after 10 min when cells were exposed to 10 micrograms/ml vinblastine or cyclohexamide. After the drug was removed vimentin-containing filaments radiated from this button through the cytoplasm. In some cells peripheral buttons appeared, up to six in one cell. Within 1 h the filaments had reformed to a normal pattern for intermediate filaments. These buttons did not form in mesenchymal cell lines, mouse; rat and 3T3 fibroblasts. They appeared only in epithelial cell lines. Monoclonal antibodies to keratin and tubulin did not stain these buttons. These appear to be discrete entities separate from the microtubule organizing centre and to be found only in cultured epithelial cell lines. This structure may act as the organization centre for vimentin in cultured epithelial cell lines.

Animals↗
PubMed1983

Immunofluorescent sites in vero cells infected with the flavivirus Kunjin.

The sites of replication and of accumulation of viral macromolecules were examined using fluorescent antibodies to viral products and to cell organelles. Synthesis of envelope protein and its accumulation in a narrow rim around the nucleus were detected at 4 hours post infection; concurrently, a progressive change was observed in the rough endoplasmic reticulum from a fine to a coarse network emanating from around the nucleus. This change in the network was visible by light microscopy. The immunofluorescent sites of viral RNA synthesis, located by use of anti-double stranded RNA, extended from the perinuclear region in another fine network which included many small foci or vesicles; these sites were also visible by light microscopy late in infection. None of these changes were associated with any visible redistribution of actin, intermediate filaments or microtubules, and no nuclear involvement was detected. However, when microtubules were disrupted by vinblastine treatment of cells, the distribution of the immunofluorescent sites of viral RNA synthesis was modified and the virus yield was reduced by at least 10-fold. These results confirmed our biochemical studies showing separation of viral sites of RNA synthesis and translation, and the accumulation of envelope protein in nuclear-associated membranes. The relevance of these observations is discussed in relation to the reports of specific membrane structures induced in flavivirus-infected cells.

Animals↗
PubMed1983

Flow microfluorometry detects IgM autoantibody to oligodendrocytes in multiple sclerosis.

Freshly isolated canine oligodendrocytes were reacted by indirect membrane immunofluorescence with 44 sera from patients with multiple sclerosis (MS). Using analysis by flow microfluorometry (FMF), we found significant IgM antibody binding to the surfaces of oligodendrocytes in the MS sera. The fluorescence intensity of cell surface reactions for MS sera (F.I. greater than 40 = 37.2 +/- 21.34%) was significantly different (P less than 0.001) to that for 53 sera from normal subjects (10.0 +/- 8.97%), 15 sera from patients with Murray Valley encephalitis (6.18 +/- 5.3%), 22 with brain tumours (6.18 +/- 5.3%), 25 with SLE (13.42 +/- 11.65%), 7 with GBS (9.77 +/- 3.9%) and 7 miscellaneous neurological disorders (6.87 +/- 3.04%). Cell surface binding was restricted to oligodendrocytes and was absorbed out by oligodendrocytes but not by liver cells or kidney cells. Oligodendrocytes were identified by conventional histology, phase-contrast optics, electron microscopy (EM) and by cell surface reactions with anti-galactocerebroside, a specific immunocytological marker for oligodendrocytes. A cell sort of the single 0 degree FMF scatter peak followed by EM examination confirmed that the reactive cells consisted exclusively of oligodendrocytes. Viability of oligodendrocytes before and after the staining reactions, was greater than 80% as assessed by trypan blue and fluorescein diacetate exclusion. The possibility that immune reactions mediated by the surface-reactive antibody with readily accessible cell surface autoantigens in vivo may contribute to the loss of oligodendrocytes and demyelination in MS is raised.

Adolescent↗
PubMed1983

Expression of glial fibrillary acidic protein, actin, fibronectin and factor VIII antigen in human astrocytomas.

Frozen sections and cell cultures of 50 human astrocytomas, fetal and adult human brain were examined for immunofluorescence reactivity with antisera to glial fibrillary acidic protein (GFAP), actin, fibronectin and factor VIII antigen. In frozen tissue sections GFAP expression was restricted to normal and neoplastic astrocytes while fibronectin and factor VIII antigen were localized to blood vessels. In primary cell culture, 80-100% neoplastic astrocytes expressed GFAP but not fibronectin or factor VIII antigen while actin was present as diffuse cytoplasmic staining of the cell body and cell processes. By the 5th-6th passage in vitro, GFAP immunoreactivity was lost while fibronectin and actin cables were prominently expressed. Factor VIII antigen remained negative throughout serial subculture. In double fluorochrome experiments, GFAP positive cells did not express fibronectin or actin cables, while GFAP negative cells expressed fibronectin and had prominent actin cables. Our results suggest a change in population of astrocytoma cells with increasing passage in vitro, reflecting either an overgrowth of tumour glioblasts or dedifferentiation of tumour astrocytes.

Actins↗
PubMed1983

ELISA assay for IgG autoantibody to G-actin: comparison of chronic active hepatitis and acute viral hepatitis.

An ELISA was developed to test for IgG autoantibody to rabbit skeletal muscle G-actin in liver disease. To express results of the ELISA, we used a single reference serum with known high anti-actin activity, and assessed binding of test sera as a percentage of that displayed by the reference antiserum. Antibody to G-actin was measured in 40 sera from patients with chronic active hepatitis (CAH), 39 from acute viral hepatitis A (Hep A), 46 from acute viral hepatitis B (Hep B), 23 from non-A, non-B hepatitis (Hep non-A, non-B), 31 from systemic lupus erythematosus (SLE), 21 from scleroderma and 93 from normal persons. The results were compared with those obtained using indirect immunofluorescence tests with frozen sections of rodent stomach or fibroblast monolayers as substrates. Anti-G-actin activity of serum was significantly higher (P less than 0.001) in CAH (mean 63% +/- 23, range 18-110) than in controls (mean 15% +/- 12, range 0-51), systemic lupus erythematosus (mean 25% +/- 16, range 8-76), scleroderma (mean 23% +/- 13, range 3-59), Hep A (mean 24% +/- 11, range 6-25), Hep B (17% +/- 8, range 2-36), or Hep non-A, non-B (mean 23% +/- 11, range 7-53). There was no significant difference (P greater than 0.05) in the occurrence of anti-G-actin activity of serum in Hep A, Hep B or non-A, non-B compared with controls. At an ELISA reading of greater than or equal to 40% (mean + 2 s.d. of controls) the assay detected autoantibodies to G-actin in 85% of CAH, compared to 80% on fibroblast monolayers and 70% on rodent stomach. The ELISA described in the present study is a simple, sensitive and quantitative assay for autoantibody to G-actin. It should prove useful in assessing subspecificities of actin antibodies in liver diseases, and in differential diagnosis, particularly CAH from acute viral hepatitis.

Actins↗
PubMed1983

A monoclonal IgM smooth muscle antibody reactive with fibroblast stress fibres produced by immunization with Treponema pallidum.

A monoclonal IgM smooth muscle antibody secreted by a hybrid (MMI-1) of mouse plasmacytoma NS-1 with spleen cells from mouse immunized with Treponema pallidum was detected by indirect immunofluorescence tests on frozen tissue sections and on acetone fixed monolayers of rat and human fibroblasts. The antibody did not react with acetone fixed smears of T. pallidum but reacted with smooth muscle fibres and with striations of skeletal and cardiac muscle. In non-muscle cells, the antibody stained liver in a 'polygonal' pattern, thymus with accentuated staining of the thymic medulla, renal glomeruli and the brush border and peritubular fibrils of renal tubules. In fibroblast monolayers, the antibody stained stress fibres in an interrupted pattern. Immunoblotting with muscle proteins and the antibody showed labelling of a 100K molecule. The cellular distribution of the mouse monoclonal antibody is similar to that obtained with anti-actin antibody suggesting that the corresponding antigen may be an actin binding protein.

Actins↗
PubMed1983

A new human breast carcinoma cell line (PMC42) with stem cell characteristics. I. Morphologic characterization.

A new human breast carcinoma cell line (PMC42) was established from a pleural effusion from a woman with metastatic breast cancer. The cells were significantly pleomorphic even after 3.5 years in continuous culture. Eight different cell types could be characterized morphologically in monolayer culture. Cells cloned in agar and replated in monolayer culture were equally heterogenous. Cells also grew in suspension in papillary clusters that structurally resembled glandular organoids. Electron microscopy confirmed the differentiated structure of these cells in which many of the features of lactating breast tissue were evident. It is proposed that this is a culture derived from a malignant breast stem that has retained its ability to differentiate in vitro.

Aged↗
PubMed1982

Segregation of autoantibody to cytoskeletal filaments, actin and intermediate filaments with two types of chronic active hepatitis.

Regional differences in serological features of chronic active hepatitis (CAH) were assessed from study of unselected patients with CAH, 53 from Zagreb, Yugoslavia and 53 from Melbourne, Australia. A group of 29 patients from Zagreb with chronic persistent hepatitis (CPH) was also included. The serological marker studied was immunofluorescence reactivity to cytoskeletal components, actin cables (AC) and intermediate filaments (IF), these being mostly responsible for the smooth muscle antibody reactivity which occurs in CAH. The Zagreb cases of CAH differed from the Melbourne cases by having a significantly lower frequency of anti-AC (8% vs 55%) and a significantly higher frequency of anti-IF (34% vs 15%), and correspondingly had a higher frequency of markers of hepatitis B virus (HBV) infection (HBsAg, 53% vs 8% and anti-HBc, 72% vs 34%), and a differing HLA profile, with HLA BW35 higher (38% vs 14%) and B8 lower (18% vs 56%). This study illustrates the differences among populations in expression of CAH, in that HBsAg is held to specify the HBV-associated type, and antibody to actin is held to specify the autoimmune type. These differences would be determined in part by environmental influences, notably HBV, and genetic influences, notably HLA, and are reflected by the differing patterns of immunofluorescence reactivity with the cellular cytoskeleton.

Actins↗
PubMed1978

Ion exchange analysis of porphyrins in urine.

An easy and cheap analysis of total prophyrin in urine is described based on the ion exchange resin Dovex 2 X 8, 50--100 mesh. Recovery of added porphyrin varied between 65 and 90% for uro- and 70 and 95% for coproporphyrin. The use of the method with internal standard is described and exemplified. Ammoniacal solutions of crystalline free porphyrins were used as standards.

Humans↗
PubMed1977

Molar absorption coefficients of porphyrin esters in chloroform determined by copper titration.

Chromatographically pure porphyrin esters free from metalloporphyrins were titrated with Cu2+ to determine the molar amount of porphyrin present. The end point of the titration was defined by a t.l.c. method detecting traces of metal-free porphyrin ester in admxture to its copper complex. From spectrometric measurement at the Soret maximum and the molar amounts found by the titration, epsilonM was calculated for proto-, copro-, penta-, hexa- and hepta-carboxylic and uro-porphyrin permethyl esters. The values for uroporphyrin showed perfect agreement with those of previous workers, whereas those for coproporphyrin were about 5% lower and those for protoporphyrin more than 20% lower. The implications of the findings are discussed. Determinations of epsilonM of some higher esters (ethyl to pentyl) and some partial methyl esters with one carboxyl group free are also presented.

Chloroform↗
PubMedDate not supplied

Vimentin intermediate filaments in cultures of human meningiomas.

Monolayer cultures of six human meningiomas and meningeal cells from a human foetus were examined by indirect immunofluorescence with a human autoantibody to intermediate filaments and with a monoclonal antibody to vimentin intermediate filaments. No difference could be demonstrated in the staining of an intricate fibrillar network in cultures of transitional, fibroblastic, psammomatous and sarcomatous meningiomas compared to those of human foetal meninges. Many meningotheliomatous meningioma cells showed staining of distinctive 'whorls' of intermediate filaments, an observation less frequently seen in fetal meningeal cells or in meningiomas of other histological types. Meningioma cells, pretreated with vinblastine, showed staining of rearranged filaments whose conformation and compactness varied from cell to cell. A striking observation frequently seen in transitional and psammomatous meningiomas was the staining of thick intermediate filament 'bands' bridging two contiguous meningioma cells. Immunoblotting experiments confirmed the presence of vimentin intermediate filaments in the cultured meningioma cells.

Cell Nucleus↗