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J S Pedersen

Publications and source records attributed to J S Pedersen.

At least 37 records · Page 2Linked to original sources
PubMed1994

The aggregation behavior of zinc-free insulin studied by small-angle neutron scattering.

The aggregation behavior of zinc-free insulin has been studied by small-angle neutron scattering as a function of pH and ionic strength of the solution. The pair distance distribution functions for the 12 samples have been obtained by indirect Fourier transformation. The results show that the diameter of the aggregates is 40 A at pH 11 and 10 mM NaCl, independent of the protein concentration. The largest diameter of about 120 A is found for pH 8, 100 mM NaCl, and a protein concentration of 10 mg/ml. Estimates of the pair distance distribution functions, free of inter-particle correlation effects, were obtained by an indirect Fourier transformation, omitting the data at small scattering vectors, which are influenced by these effects. By this procedure the weight-averaged molecular mass and the average radius of gyration were determined. These parameters vary from 1.3 times the monomer mass and 14 A, to 6.8 times the monomer mass and 31 A, respectively. The mass distribution between the oligomers was determined by a model based on the crystal structure of zinc-free insulin. The results from this model and the Fourier transformations have been compared to an equilibrium model recently introduced by Kadima et al. (1993). The neutron scattering results agree well with the predictions of this model except that broader mass distributions are suggested by neutron scattering.

Crystallization↗
PubMed1993

Structure of clathrin-coated vesicles from small-angle scattering experiments.

Previously published small-angle neutron and X-ray scattering data from coated vesicles, reassembled coats, and stripped vesicles have been analyzed in terms of one common model. The neutron data sets include contrast variation measurements at three different D2O solvent concentrations. The model used for interpreting the data has spherical symmetry and explicitly takes into account polydispersity, which is described by a Gaussian distribution. A constant thickness of the clathrin coats is assumed. The fitting of the model shows that the coated vesicles consist of a low-density outer protein shell (clathrin) and a central protein shell (accessory polypeptides and receptors) of approximately six times higher density. For the X-ray scattering and neutron contrast variation data, the polydispersity of the samples is of the order of 90 A (full-width-at-half-maximum value) and the average outer radius is approximately 400 A. The inner high-density shell has inner and outer radii of 115 and 190 A, respectively. A simultaneous fit to the three neutron contrast variation data sets identifies the lipid membrane with a thickness of 40 A and an outer radius of 196 A. Thus, the membrane and the high-density protein shell overlap in space, which shows that the lipid membrane contains protein. The molecular mass of the average particle is 27 x 10(6) Da. The coated vesicles consist, on average, of approximately 85% protein and 15% lipids. About 40% of the protein mass is situated in the central high-density shell, which gives a large amount of protein in the lipid membrane. The densities of the central shell and the lipid membrane show that the hydration is small in the central region. A comparison of the total mass, the mass distribution, and the structure of the average-size particles with the barrel structure shows that the accessory polypeptides are incorporated in the lipid membrane. The results from the neutron data for the reassembled coats show that the structure of these particles is very similar to the structure of the native coats. The main difference is a higher density of the central protein shell, which shows that the membrane is replaced by protein in the reassembled coats.

Clathrin↗
PubMed1992

Contrast variation studies of clathrin coated vesicles by small-angle neutron scattering.

Structural information on clathrin coated vesicles has been obtained by small angle neutron scattering using contrast variation. A characteristic peak in the neutron scattering profile, which is apparent in 75% D2O, as well as in H2O, disappears when contrast matching the protein component of the coated vesicles in 42% D2O. Neutron, as well as dynamic, light scattering give a coated vesicle size of about 900 A in H2O and D2O, but for neutron scattering the diameter decreases when matching out the protein coat of the clathrin coated vesicles. From the match point for the clathrin coated vesicles it is demonstrated that the clathrin cages do contain internal membrane. The mass of 34 MD and composition of 75% protein and 25% lipid found from the analysis of the small-angle scattering data are both in good agreement with the values reported in the literature. Electron microscopy gives an average outer diameter of 880 A for the coated vesicles and an average diameter of 460 A for the vesicle itself.

Biophysical Phenomena↗
PubMed1992

Excimer laser angioplasty in the atherosclerotic rabbit: comparison with balloon angioplasty.

The early and late results of excimer laser angioplasty and balloon angioplasty were compared in atherosclerotic rabbit iliac arteries. Immediately after laser angioplasty (n = 13) with a bare 600 microns fiber, there was a 33% increase in angiographically measured minimum lumen diameter; after balloon angioplasty (n = 12), there was a 53% increase. Restenosis (defined as loss of at least 50% of the gain achieved by angioplasty) occurred in none of six laser-treated rabbits studied 1 month later, compared with four of six balloon-treated rabbits (p = 0.06). Planimetric measurements of cross sections of the arterial wall 1 month after angioplasty showed less intimal and medial tissue in laser-treated (1.8 +/- 0.2 mm2) than in the balloon-treated rabbits (3.0 +/- 0.4 mm2; p less than 0.05). Typical thermal effects were absent on microscopic examination of laser angioplasty sites. It is concluded that in this animal model, excimer laser irradiation results in an immediate increase in lumen diameter comparable with balloon angioplasty, but is associated with less residual atheromatous tissue than balloon angioplasty and a trend toward a lower rate of restenosis.

Angioplasty, Balloon↗
PubMed1991

Endocrine cell carcinoma of the gallbladder.

An endocrine cell carcinoma in the gallbladder of a 59-year-old woman is reported. The morphological features of this diagnosis are compared with 14 previously reported primary gallbladder carcinoid tumours that had metastasized. The histogenesis and current classification of endocrine cell tumours is discussed.

Adenocarcinoma, Scirrhous↗
PubMed1991

Ocular surface and lacrimal disturbances in chronic graft-versus-host disease: the role of conjunctival biopsy.

Forty-four patients (21 male, 23 female) were studied following bone marrow transplantation (BMT): 40 after allogeneic, one after syngeneic and three after autologous transplantation. Diffuse punctate conjunctival and corneal epitheliopathy was seen in 27 (61%), reduced or disordered tear film in 26 (59%), acquired lacrimal outflow obstruction in three (7%) and posterior subcapsular lens opacities in five (12%) patients. Conjunctival histology showed abnormal features, including those of graft-versus-host disease (GVHD) in 41 patients. Of these, 28 (64%) had clinical and laboratory features of GVHD and six patients with no systemic evidence of GVHD had conjunctival histology specific for GVHD. We conclude that after BMT, subclinical changes of GVHD are very common in the periocular tissues and may be universal in long-term survivors following allogeneic BMT. Some minor conjunctival changes are more likely to be due to the primary disease or the transplant conditioning regimen. Conjunctival biopsy is useful in demonstrating low-grade GVHD or GVHD confined to the ocular structures and may be diagnostic in some cases.

Adolescent↗
PubMed1991

Transfusion associated graft-versus-host disease after cardiac surgery: response to antithymocyte-globulin and corticosteroid therapy.

A 63-year-old patient developed graft-versus-host disease (GVHD) after the transfusion of stored, random donor red cell concentrates with coronary artery surgery. The disease was characterised by skin rash, fever, diarrhoea, hepatic dysfunction, pancytopenia and the acquisition of cells bearing human leukocyte antigens of a blood donor. Clinical and histologic improvements were noted with antithymocyte-globulin and corticosteroid therapy, as seen in some patients with acute GVHD following allogeneic bone marrow transplantation, but the pancytopenia failed to resolve prior to a fatal cerebral haemorrhage. Early aggressive immunosuppressive therapy may be beneficial for transfusion-associated GVHD but strategies for its prevention by limitation of the use of homologous blood need to be addressed.

Antilymphocyte Serum↗
PubMed1987

Distribution by immunofluorescence of viral products and actin-containing cytoskeletal filaments in rubella virus-infected cells.

Rubella virus (RV)-host cell interactions were examined by indirect immunofluorescence staining using antibodies to viral products and cytoskeletal components as probes. The patterns of immunofluorescence observed with human convalescent sera indicated that in infected Vero cells RV-specified proteins were distributed throughout the rough endoplasmic reticulum with some possible accumulation in the region of the Golgi complex. Viral RNA synthesis, detected with anti-double stranded RNA, appeared to be confined to small, intensely stained foci irregularly distributed in the cytoplasm. When cells were infected at a higher multiplicity, these foci appeared to aggregate into linear arrays. Infection with RV had a profound effect on the organization of actin in both Vero and BHK 21 cells, as shown by anti-actin antibodies. Actin microfilaments were observed to disintegrate progressively into amorphous aggregates of apparently monomeric actin as the infection proceeded. Because of the role actin microfilaments may play in cell mitosis it is postulated that this effect may be related to the inhibition of cell division reported to be associated with the congenital rubella syndrome.

Actin Cytoskeleton↗
PubMed1987

Autoantibody to aldolase in acute and chronic hepatitis.

Sera from 82 patients with acute or chronic hepatitis and 40 chronic carriers of hepatitis B were examined by ELISA and immunoblotting for reactivity with the glycolytic enzyme aldolase. The results of the ELISA tests, expressed as a percentage of a positive control, were compared to those obtained with sera from 39 patients with rubella, 11 with cytomegalovirus infection and 74 healthy subjects. The ELISA reaction with sera, expressed as mean +/- standard deviation was, for 15 patients with hepatitis A, 58.3 +/- 20.5%; 15 with hepatitis B, 59.5 +/- 42.18; 23 with hepatitis non-A, non-B 51.1 +/- 34.4%; 11 with HBsAg positive chronic active hepatitis, 70.1 +/- 31.5%; and 17 with autoimmune chronic active hepatitis, 66.8 +/- 21.4%. All values were significantly (p less than 0.05-p - less than 0.001) higher than those obtained with sera from carriers of hepatitis B surface antigen, 25.6 +/- 27.2%; rubella, 21.1 +/- 20.0%; cytomegalovirus infection, 19.2 +/- 27.8%; or healthy subjects, 20.9 +/- 16.2%. In two randomly selected sera, reactivity with aldolase by ELISA was neutralized by absorption with the enzyme. Selected sera showing reactivity by ELISA reacted by immunoblotting with aldolase. The findings suggest that acute or chronic liver damage may provoke the production of autoantibodies to aldolase.

Acute Disease↗
PubMed1986

Identification and characterization of mitochondria autoantigens in progressive systemic sclerosis: identity with the 72,000 dalton autoantigen in primary biliary cirrhosis.

Sera from eight out of 62 (14.5%) patients with progressive systemic sclerosis (PSS) reacted by immunoblotting with a 72,000 dalton antigen and one, a patient with concomitant primary biliary cirrhosis (PBC), reacted with the 72,000 dalton and a 47,000 dalton antigen. Reactivity with these antigens was not seen with any of 111 control sera. The antigens with minor variations in m.w. were present in a variety of cultured cells and tissue homogenates from different species. Subcellular fractionation studies localized the antigens to the mitochondria. Of 19 sera from patients with other diseases selected for immunofluorescence staining for anti-mitochondria autoantibody, nine reacted with the 72,000 dalton antigen, seven reacted with both the 72,000 and 47,000 dalton antigens, and three reacted with the 47,000 dalton antigen. These results show that serum reactivity with the 72,000 dalton and 47,000 dalton mitochondria autoantigens is found with some patients with PSS. Because mitochondria autoantibodies that are reactive with the 72,000 dalton and 47,000 dalton polypeptides are also found in patients with PBC, the present finding provides additional support for the association of PSS with PBC. Prior absorption of rat liver homogenate with PBC sera removed PSS serum reactivity with a 63,000 dalton antigen, the equivalent 72,000 dalton antigen in rodents, and vice versa, showing that both PBC and PSS sera recognize the same antigen.

Animals↗
PubMed1986

Development of increased serum immunoblot reactivity against a 45,000-dalton polypeptide of Treponema pallidum (Nichols) correlates with establishment of chancre immunity in syphilitic rabbits.

Rabbits developed chancre immunity 5.0 to 7.5 weeks after intradermal infection with 10(3) Treponema pallidum (Nichols). The serological response against T. pallidum antigen during this 2.5-week period was examined by Western immunoblotting. Sera from rabbits infected for 5.0 weeks contained antibodies against 7 of 13 major T. pallidum immunogens, with strongest binding detected against a polypeptide of Mr 47,000. By 7.5 weeks of infection, syphilitic rabbit sera recognized 10 of 13 antigens; the most evident increase in serological reactivity was directed against a polypeptide of Mr 45,000, suggesting that the development of a strong serological response against this polypeptide correlated with the onset of chancre immunity.

Animals↗
PubMed1986

Sporidesmin and gliotoxin induce cell detachment and perturb microfilament structure in cultured liver cells.

Changes in cell morphology and cell adhesion occurred when cultured cells from the rat liver cell strain C3 were exposed to the fungal toxins, sporidesmin or gliotoxin. Both toxins caused loss of attachment of the cells to the plastic of tissue culture plates and this effect was preceded by loss of actin cables. Other changes included cytoplasmic vacuolation and blocked entry into S-phase of the cell cycle. Under these conditions [3H]thymidine incorporation into the cells was also diminished but changes were not detected in the amount of cellular actin, or in the accessibility of cell surface proteins to iodination carried out by the Bolton and Hunter method. The observations suggest that disruption of microfilaments is one of the earliest effects of these toxins on eukaryotic cells.

Actin Cytoskeleton↗
PubMed1986

Scl-95/100: doublet of endothelial marker autoantigens in progressive systemic sclerosis.

Thirteen out of 60 sera (22%) from patients with progressive systemic sclerosis reacted by immunoblotting with a doublet of 95 kD and 100 kD proteins in endothelial cells of human and bovine origin. Reactivity with the doublet was not seen in any of 125 control sera. The endothelial doublet was localized to the nucleus by immunoblot reactivity with nuclear subcellular fractions but not with mitochondrial, microsomal or soluble subcellular fractions. In HEp-2 cells and in HeLa cells, positive sera reacted with the 100 kD antigen, but not with the 95 kD antigen. Identical immunoblot reactivity was obtained with a standard reference serum containing anti-scl-70 activity by immunodiffusion. All positive sera also reacted with cell nuclei by indirect immunofluorescence and 10 gave anti-scl-70 reactivity by immunodiffusion. These observations suggest that the 95 kD/100 kD doublet may be a larger form of the Scl-70 autoantigen.

Adult↗
PubMed1986

Autoantibodies to creatine kinase in rabbits infected with Treponema pallidum.

Sera from rabbits infected intratesticularly with Treponema pallidum (Nichols) for 30 days were examined for autoantibody reactivity against muscle and testis extracts by Western immunoblotting. Syphilitic sera (30 day) reacted with an autoantigen of 43,000 daltons in muscle extracts. The antigen was shown to be creatine kinase (CK). Studies with the use of an anti-CK ELISA showed that the autoantibody to CK first appeared 3 wk after infection, declined by 7 wk infection, and was absent in rabbits "mock"-infected with heat-killed T. pallidum. CK activity was not detected in sonicated or intact, washed T. pallidum, suggesting that the antibody was not produced in response to treponemal CK.

Animals↗
PubMed1985

Antibody to G-actin in different categories of alcoholic liver disease: quantification by an ELISA and significance for alcoholic cirrhosis.

Autoantibodies to smooth muscle (ASMA), and to actin which is a major determinant of such reactivity, were measured in the serum of 94 patients with three defined categories of alcoholic liver disease, fatty liver, alcoholic hepatitis, and alcoholic cirrhosis, and in controls matched individually by age and sex with the patients. Autoantibody to monomeric G-actin was detected by an ELISA and autoantibody to polymeric F-actin by immunofluorescence staining of fibroblast stress fibers in cultured cells. Values for the ELISA were expressed as a percentage of the value for a strongly reactive standard serum. The mean value for antibody to G-actin in 40 patients with alcoholic cirrhosis (70 +/- 33%) was significantly greater than that for the matched controls (28 +/- 18%), but the mean value for the 30 patients with alcoholic hepatitis (46 +/- 16%) and the 24 with fatty liver (42 +/- 24%) did not differ significantly from the controls. High levels of reactivity with G-actin correlated significantly with HLA B7. ASMA was demonstrable to low titer in 11 of the 94 sera, and positive ASMA reactions by immunofluorescence correlated with high binding values to G-actin in the ELISA. Antibody to F-actin was found in only one serum and no controls. Thus in different liver diseases the reactivity of antibodies to monomeric G-actin and polymeric F-actin may differ, presumably because of specificity for different determinants of the actin molecule. Reactivity to G-actin may distinguish a group of alcoholic subjects in whom a predisposition to autoimmune reactivity is one of the determinants of progression of liver damage to cirrhosis.

Actins↗
PubMed1985

Hybrids from normal, germ free, nude and neonatal mice produce monoclonal autoantibodies to eight different intracellular structures.

The supernatants of hybrids produced by fusion of splenocytes from normal, germ free, nude and neonatal BALB/c mice with mouse NS-1 myeloma cells were examined for immunofluorescence reactivity with viable and acetone fixed monolayers of syngeneic mouse fibroblasts and mouse 3T3 cells and with viable cell suspensions of syngeneic mouse erythrocytes and thymocytes. The supernatants of 70 out of 419 (16.7%) hybrids from normal mice, 87 out of 627 (13.9%) from germ free mice, 28 out of 240 (11.7%) from nude mice and 42 out of 1020 (4%) from neonatal mice reacted with 8 different intracellular structures in mouse fibroblasts and 3T3 cells, and with rat and human fibroblasts. The reactive intracellular structures comprised stress fibres, intermediate filaments, cell membrane associated, golgi complex, cytoplasm, cytoplasmic vesicles, mitochondria and nuclei. Of 45 stable clones derived by limiting dilution, 43 produced IgM antibodies and two IgG2b antibodies. Only one out of the 2,306 (0.04%) hybrids produced an autoantibody to the surface membrane of mouse thymocytes. These results show that B cells with reactivity towards different intracellular structures are present in the normal B cell repertoire whereas surface reactive B cells may be deleted or more profoundly suppressed or anergic and unable to form viable Ig producing hybridomas.

Animals↗
PubMed1985

Monoclonal antibody to myosin derived from mice immunized with gastric mucosal cells.

A monoclonal IgMk antibody secreted by a hybrid (MUI-6) of mouse plasmacytoma NS-1 with spleen cells from a mouse immunized with canine parietal cell-enriched gastric mucosal cells was tested for immunofluorescence reactivity with gastric mucosal cells, tissue sections and monolayer cultures of rat fibroblasts. The antibody did not react with the cell membrane of parietal cells but reacted with smooth muscle fibres and skeletal muscle striations. In non-muscle cells, the antibody reacted with parietal cell cytoplasm, liver in a "polygonal" pattern, renal glomeruli, brush borders and peritubular fibrils of renal tubules, thymic medulla, brush borders of small intestinal mucosal cells, and cerebellar astrocytes, synaptic endings and synaptic glomeruli. In fibroblast monolayers, the antibody stained stress fibres in an interrupted pattern and in spreading fibroblasts, the antibody stained the microfibrillar network. Stress fibre staining was disrupted by treatment of cells with cytochalasin B. Immunoblots showed that the antibody reacted with a 200 K protein in 3T3 cells and with a preparation of myosin from rat liver.

Animals↗