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R Thorstensson

Publications and source records attributed to R Thorstensson.

At least 73 records · Page 4Linked to original sources
PubMed1987

Anticardiolipin antibodies in patients with systemic lupus erythematosus.

We studied a group of 59 unselected patients with systemic lupus erythematosus (SLE); these patients were from a defined population who lived in southern Sweden. We found that serum concentrations of anticardiolipin antibodies were increased in 32 SLE patients (54.2%). No significant correlation between increased amounts of anticardiolipin antibodies and clinical symptoms, such as thrombocytopenia or thrombosis, was found. Serial serum samples from 28 patients (12 patients were from the epidemiologic cohort) were analyzed. Sixteen of these 28 patients (57.1%) had increased levels of anticardiolipin antibodies; in most cases, there was no variation in these values with regard to clinical disease flares or treatment. Increased concentrations of anticardiolipin were observed in 4 patients with cerebral infarction. However, very high concentrations of anticardiolipin antibodies were observed in several patients with inactive SLE who had no history of thrombosis or thrombocytopenia. Our results underscore the importance of studying unselected patient groups when correlating laboratory data with clinical manifestations of disease.

Adult↗
PubMed1985

Preparation of highly purified F-actin-depolymerizing factor of human serum.

F-actin depolymerizing factor (ADF) of human serum was purified 250-400-fold to more than 98% purity with high reproducibility. The purification included (1) 30-50% (NH4)2SO4 precipitation, (2) ion-exchange chromatography on DEAE-Sepharose, (3) chromatofocusing on Polybuffer exchanger 94 and (4) affinity chromatography on ConA-Sepharose. The recovery of ADF was estimated to be 20-30% whereas the ADF activity yield was 5-17%. The lower activity yield was thought to be due-partly to proteolysis and partly to destabilization of highly purified ADF.

Actin Depolymerizing Factors↗
PubMed1984

Reactivity of sera from patients with liver disease with glutaraldehyde-treated erythrocytes: role for false positive results in hemagglutination tests.

The use of glutaraldehyde as a coupling reagent in the passive hemagglutination test (HA) has gained wide application, especially for the coating of red blood cells (RBC) with glutaraldehyde-polymerized human serum albumin (pHSA), for studies of the albumin receptor on hepatitis B surface antigen (HBsAg) or for the detection of anti-albumin antibodies (AAA). Here we report a previously unrecognized reactivity with glutaraldehyde-treated RBC mainly with sera from patients with liver disease. The highest incidences of this reaction were found in patients with acute viral hepatitis A and B, namely 44 of 50 (88%) and 31 of 50 (62%) respectively. In 234 HBsAg carriers the frequency was low (3%). This reactivity was also observed in 19 of 50 sera from patients with chronic liver disease documented by biopsy, but not in sera from 68 healthy subjects. By immunofluorescence on glutaraldehyde-treated RBC it was shown that the corresponding antibodies belonged mainly to the IgM class. In all HBsAg-negative patients studied the HA titer against glutaraldehyde-treated RBC was in agreement with the titer against RBC coated with pHSA or pBSA (polymerized bovine serum albumin). Absorption with pHSA abolished the reaction with glutaraldehyde-treated RBC in 7 of 8 sera, suggesting a common reactivity between glutaraldehyde-polymerized HSA and glutaraldehyde-treated RBC. Apart from the possible clinical importance of these antibodies, their existence is a possible source of false positive results when glutaraldehyde is used as a coupling reagent for immunological assays, in particular with sera from patients with liver diseases.

Actins↗
PubMed1984

Further immunological studies of sera containing anti-mitochondrial antibodies, type M 5.

All of 15 sera containing anti-mitochondrial antibodies (AMA), type M 5, reacted in ELISA with ssDNA, whereas only four had anti-nuclear antibodies as demonstrated by immunofluorescence technique. Twelve of 15 had biological false-positive seroreaction for syphilis and seven of 11 cases investigated had a positive lupus anti-coagulant test. Cold agglutinins were present in 11 sera. Hyper-gamma-globulinaemia was not a prominent finding, but C4 values below the lower limit were common in spite of C3 within the normal range. Absorption of IgG fractions from three different sera with cardiolipin eliminated the reaction with ssDNA and mitochondria, supporting a certain degree of cross-reactivity among the antibodies. The presence of AMA, type M 5, seemed to discriminate a group of patients with symptoms often consistent with SLE although some of the most prominent findings were often absent.

Adult↗
PubMed1983

Antigenicity of Entamoeba histolytica strain nih 200: a survey of clinically relevant antigenic components.

The molecular weights of the major polypeptides of Entamoeba histolytica NIH 200 soluble whole extract, and its five fractions eluted from a Sephadex G-200 column, were in the range 150,000-9,000 daltons according to sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Autoradiography of SDS-PAGE analysis of 125I surface-labeled amebae revealed more than 12 bands, eight of which corresponded to those recovered in soluble extract. Considering the pronounced phagocytosis and the rapid cell membrane turnover of the ameba, it seems likely that the same antigenic components would be present both on and within the ameba at different stages. The first four gel-filtered fractions were immunogenic and showed non-identical precipitates with sera from 12 Swedish and 12 Ethiopian patients with verified amebic disease. Seven polypeptides in the whole extract reacted with human anti-ameba IgG covalently bound to CNBr activated Sepharose 4B. Immune replica (Western blotting) of SDS-PAGE of whole extract produced by human anti-ameba antisera demonstrated eight bands. The response to the different amebic antigens was not correlated to clinical symptoms, duration of illness or origin of ameba strain. Thus the present results did not support the use of purified fractions rather than the whole soluble extract for diagnostic tests.

Antigen-Antibody Complex↗
PubMed1982

Non-specific precipitin reactions of IgG at low ionic strength.

Precipitin reactions apparently not involving specific antibodies were obtained in immunodiffusion experiments performed at low salt concentration between IgG and the muscle proteins, actin and tropomyosin. The precipitates, which dissolved at physiologic ionic strength, may result from electrostatic interaction of molecules of different net charge and different distribution and number of charged groups.

Actins↗
PubMed1982

Further characterization of the Ca2+-dependent F-actin-depolymerizing protein of human serum.

The F-actin-depolymerizing factor (ADF) of human serum was purified and identified as a 93000-daltons protein. The concentration of ADF was calculated to 120-150 micrograms/ml in four normal sera and about half as much in three sera from leukemia patients treated with cytostatic drugs. In the presence of Ca2+ ADF shortened actin filaments into fragments, the size of which was correlated to the actin: ADF molar ratio, as judged by electron microscopy. The severing of F-actin was not necessarily followed by an increase in the quantities of monomeric actin, as determined by a DNase I inhibition assay and a sedimentation assay. The findings indicated that ADF shortens filamentous actin by breaking bonds between adjacent actin molecules thereby forming stable ADF-actin complexes, without a monomeric net release. The effect of ADF on F-actin was rapid and was reversed upon chelation of Ca2+. ADF cross-reacted immunologically and exhibited similarity in reaction mechanism with gelsolin, the Ca2+-dependent F-actin-severing protein from macrophages. This implies that the proteins are both structurally and functionally related. The physiological role of ADF may be to handle actin released at cell destruction, probably by forming ADF-G-actin 1:1 complexes thereby preventing formation of actin filaments.

Actin Depolymerizing Factors↗
PubMed1981

A radioimmunoassay for determination of anti-actin antibodies.

The reaction of spontaneously occurring human anti-human antibodies and experimentally produced rabbit anti-actin antibodies was investigated in a solid-phase radioimmunoassay (RIA). Three structurally different in vitro forms of actin monomeric G-actin filamentous F-actin and aggregated denatured actin were used as antigens. Human anti-actin antibodies reacted with F- and G-actin but not with aggregated actin, while rabbit anti-actin antibodies gave a strong reaction with all 3 forms of actin indicating differences in antibody specificities. The results of the anti-actin RIA were compared with those obtained by indirect immunofluorescence (IFL) on cryostat sections of rat stomach. The anti-actin RIA discriminated between patients' sera and control sera in most cases, although the indirect IFL test gave more conclusive results. The seemingly low sensitivity of the anti-actin RIA compared with that of indirect IFL test for detection of human anti-actin antibodies is probably due to favourable antigen distribution in tissue, not available in the solid phase. The anti-actin RIA was able to detect anti-actin antibodies in 8 out of 8 immunized rabbits although only two produced antibodies detectable by indirect IFL. The differences in reactivity between the two methods may depend on the presence of aggregated denatured actin in the antigen preparation used for immunization and exposure of the corresponding antigenic determinants of actin on the solid phase.

Actins↗
PubMed1981

Dynamics of the interaction between Entamoeba histolytica and components of the immune response. III. Fate of antibodies after binding to the cell surface.

Binding to the surface of living E. histolytica trophozoites of 125I-labelled anti-amoeba antibodies or of such antibodies and antiglobulin resulted in a rapid disappearance of the antibody into the medium. This disappearance consisted of a rapid temperature-independent and a subsequent slow temperature-dependent phase. The disappearance of antibody from fixed trophozoites merely consisted of a temperature-independent rapid phase whereas no slow phase was observed. The magnitude of the rapid phase of antibody disappearance was virtually the same in living and fixed cells. During culture of living trophozoites for 4 h the amount of iodine-labelled material sedimenting lighter than monomeric IgG increased from 2% to 14% of all labelled material in the case of the single antibody layer. The corresponding values for the double layer were 2% and 32%. Of the material lighter than IgG, 10% of that in the single layer and 26% of that in the double layer were detected in the medium. Thus, during the 4-h culture period 25% of the originally amoeba-bound single layer of antibody probably disappeared from the cells not complexed with antigen, 27% disappeared as complexes heavier than IgG, 10% disappeared as material lighter than IgG, and 38% persisted on or within the cells. The corresponding values for the double layer of antibody were 10%, 30%, 26% and 34%.

Animals↗
PubMed1979

F-Actin-depolymerizing activity of human serum.

Non-heated human and animal sera contain a factor which exhibited an inhibiting activity on the staining of actin-containing structures by anti-actin antibodies in indirect immunofluorescence experiments. The presence of this factor lowered the viscosity of F-actin preparations and caused, as studied by electron-microscopy, a depolymerization of F-actin filaments as well as inhibition of filament formation of G-actin. The factor was, after its reaction with F-actin, liberated seemingly unaffected, indicating an enzymatic activity. The factor tentatively termed 'F-actin depolymerizing factor' was heat-sensitive and trypsin sensitive but resisted reduction. It was Ca2+ dependent and the staining inhibiting reaction was faster at 30 degrees C and 37 degrees C than at lower temperatures. Gel filtration experiments on Sephadex G-200 suggested a molecular size of the actin depolymerizing factor slightly higher than that of albumin. The electrophoretic mobility was that of gamma 2 globulin. The physiological role of the factor might be to prevent the presence of F-actin filaments within the circulation.

Actins↗
PubMed1977

The reaction of cells with anti-actin sera in relation to the amount of cellular actin.

The staining pattern of anti-actin sera on various cells smeared on glass was compared to the relative amount of cellular actin estimated by SDS-polyacrylamide-gel electrophoresis with subsequent scanning of the gel. Although the cells showed a varying stainability the actin content was fairly constant. Thus, the staining differences reflected changes in the organization of cellular actin rather than actual differences in the amount of actin.

Actins↗
PubMedDate not supplied

Visceral leishmaniasis in Somalia: prevalence of markers of infection and disease manifestations in a village in an endemic area.

Prevalence and disease manifestations of visceral leishmaniasis (VL) were studied in a Somali village in an area which has long been known to be endemic for VL. Demographic data were collected from 102 households, comprising 438 inhabitants. Clinical examination was performed of 306 individuals, 72% of the 426 eligible persons. Of these, 276 (90%) agreed to give blood and 246 (80%) to be skin tested with leishmanin. Leishmanin reactions were positive; in 26% anti-Leishmania antibodies were detected in 11%, and splenomegaly was recorded in 14% (23% of those who were seropositive). Malaria was hypoendemic and therefore unlikely to be responsible for more than 10% of the cases with splenomegaly. Three of the seropositive villagers with splenomegaly complained of feeling ill. The remaining 91 sero- and/or leishmanin-positive individuals had no complaint regarding their health and had not experienced any long period of illness. There was a slight over-representation of males in the group of sero- and/or leishmanin-positive villagers, possibly due to a gender-associated difference in exposure to the parasite. Among the patients with clinical VL treated at Mogadishu hospitals during 1989 and 1990, the male/female ratio was 3.3:1, which may indicate a selection of male patients for hospital care. Most patients were < or = 15 years old, suggesting that the highest risk of becoming clinically ill was among children.

Adolescent↗