Biomedical subjects

L M Bjursten

Publications and source records attributed to L M Bjursten.

47 records · Page 3Linked to original sources

PubMed1983

Spot immunoprecipitate assay in gel compared with immune reactions in solution and applied to antibody titration.

Precipitation profiles of spot immunoprecipitate assay (SIA) reactions in gel are shown to have characteristics analogous to classic precipitin curves representing such immune reactions in solution. Thus SIA profiles of precipitated human albumin (HSA) and anti-HSA as checkerboard analysis permit: (1) determination of optimal proportions of antibody and antigen, (2) titration of antiserum as to antigen-binding capacity and (3) estimation of the concentration of specific antibody in an antiserum. The validity of the method was confirmed by similar results already reported for precipitin analysis of anti-HSA in solution. The stained protein assay method for determination of total protein used for the calculations had a reliable (r = 0.9979) working range for quantification between 0.1 and 0.83 microgram protein in 3 microliters samples (greater than or equal to 0.03 g/l). Study of SIA profiles in the extreme antibody excess region confirmed the validity of SIA quantification. The high sensitivity of SIA as compared with radial immunodiffusion is related to high ratios (8-9) of antibody to antigen; the reliable detection limit for SIA is 10 mg/l in a 3 microliters sample. SIA is easy to perform with simple laboratory equipment, allows measurement of any precipitable antigen with very small amounts of reactants, and gives results within an hour.

Albumins↗

PubMed1983

False positive results in class-specific rheumatoid factor (RF) assays due to interaction between RF and Fc fragments of anti-immunoglobulin indicator reagents.

A recently developed, simple immunological method, diffusion-in-gel ELISA, has been adapted for class-specific determination of rheumatoid factor (RF). Evidence was obtained of an analytical error due to interaction between RF and antigenic determinants on the Fc part of the indicator immunoglobulin (Ig) molecules used. This was eliminated by replacing the usual indicator reagent, complete Ig molecules, by conjugated Fab or F(ab')2 fragments. The findings imply that unless the RF-Fc interaction mentioned is avoided in the assaying technique, false positive results may be obtained for, e.g. IgG RF and IgA RF in sera containing IgM RF.

Antibodies, Anti-Idiotypic↗

PubMed1983

Failure to detect immune complexes in the secondary stage of pityriasis rosea.

Thirty-three patients with pityriasis rosea were studied with regard to the possible presence of circulating and cutaneously deposited immune complexes. The levels of circulating immune complexes, determined by a solid-phase C1q-binding assay, were not different from those of healthy control individuals. The levels were similar in samples obtained during the initial and during the remission stages of the disease. Cutaneous deposits of immunoglobulin and/or complement were found in only 5 of 33 patients. This study does not support of concept that circulating immune complexes are important for the development of the secondary skin lesions in pityriasis rosea.

Adolescent↗

PubMed1983

The kinetics of leucocyte migration into rabbit knee joints elicited by preformed immune complexes with different in vitro characteristics.

Immune complexes were formed in vitro with antibodies obtained from rabbits immunized with bovine serum albumin in Freund's complete (FCA) or incomplete (FIA) adjuvant. The antibodies were mixed with different amounts of antigen. Immune complexes formed at maximum precipitation proportions were efficient in complement activation, whereas immune complexes formed at antigen excess had weak complement-activating properties. When injected into rabbit knee joints, the immune complexes formed at maximum precipitation proportions with FCA or FIA antibodies caused a moderate leucocyte migration into the joints with maximum cell counts 6-8 hr after injection. Injection into the joints of immune complexes formed with FCA antibodies at antigen excess induced a pronounced leucocyte migration with maximum numbers 18 hr after injection. Immunofluorescent studies indicated that these immune complexes became associated with the leucocyte membrane, whereas immune complexes formed at maximum precipitation proportions were found in the leucocyte granulae, indicating that only the complement-activating immune complexes were efficiently eliminated.

Animals↗

PubMed1981

Immune complexes, rheumatoid factors, and cellular immunological parameters in patients with giant cell arteritis.

Circulating immune complexes were found in 2 of 15 patients with giant cell arteritis (GCA) by using a solid phase Clq enzyme linked immunoabsorbent assay (ELISA). The prevalence in controls was 5%. Rheumatoid factor could be demonstrated in 2 out of 27 patients and in 11% of the controls by using a similar ELISA technique. The prevalence of T cells in blood was similar in 25 patients with GCA and in controls. The blood lymphocyte blastogenic response to the mitogens, phytohaemagglutinin, concanavalin-A, and pokeweed mitogen did not differ in 25 untreated patients compared with controls. Stimulation of lymphocytes by arterial homogenates was tested in 8 patients. In no case could a significant simulation by obtained. We conclude that immune complexes and rheumatoid factors are present in the same low frequency in GCA patients as in the normal population, and that the studied parameters of cellular immunity appear to be normal.

Aged↗

PubMed1981

Joint inflammation in rabbits induced by preformed immune complexes.

The rabbit knee joint was used to evaluate the inflammatory properties of immune complexes with different contents of antigen. Immune complexes made in vitro with antiserum from hyperimmunized rabbits and bovine serum albumin as antigen were injected into the joints. The reactivity of the individual animal was established by injection of normal rabbit serum into the contralateral joint. The number of leukocytes washed out from the joints at fixed intervals was used as a measure of the inflammatory properties of the immune complexes. With immune complexes formed at antigen excess the highest numbers of leukocytes, with a predominance of granulocytes, were found after 6 h of exposure. However, these complexes gave only weak complement activation in vitro, measured with a hemolysis assay. Complexes formed at optimal precipitation proportions gave high complement activation in vitro but only a small number of leukocytes in the joints at 6 h exposure. This finding may be explained by a rapid phagocytosis of the latter complexes while complexes formed at antigen excess are not readily phagocytized. This hypothesis is supported by the observation that higher leukocyte counts were found after shorter exposure times to complexes formed at optimal precipitation proportions than after exposure to complexes with antigen excess.

Animals↗

PubMed1981

Evaluation of circulating immune complex-like material for development of skin reactions in connection with penicillin therapy.

The levels of immune complex-like material in serum from 18 patients in connection with skin eruptions appearing during penicillin therapy were determined with a modified ELISA. Immune complex-like material could only be shown in the serum of 3 out of the 17 patients. However, according to ELISA results, the complexes appeared without the simultaneous presence of penicilloyl-specific antibodies. Neither could penicilloyl-specific antibodies be recorded in 9 patient treated with parenteral penicillin without adverse reactions. 3 of these patients had immune complex-like material in their serum. It was concluded that immune complex-like material with penicilloyl specificity is not likely to contribute to the development of skin eruptions often seen in connection with penicillin treatment.

Adolescent↗

PubMed1981

Determination of wound strength for quantitation of skin damage after pressure ischemia. An experimental study in rabbits.

Rabbits skin folds were placed in plexiglass chambers enabling control of the skin fold temperature during cuff compression (200 mmHg) for 4 hours. In 10 animals the skin folds were kept at 36 degrees C - in another 10 animals the skin fold temperature was lowered to 10 degrees C. To quantitate the skin injury caused by the pressure ischemia a standardized wound was made, and immediately closed, after release of pressure. Control wounds were made in normal skin. Seven days later the mechanical strength of the wounds was tested by determination of breaking load. There was no significant difference in breaking load between the wounds made in normal skin and in the skin folds kept at 10 degrees C, whereas the breaking loads was significantly decreased in the wounds made in skin folds kept at 36 degrees C, i.e. normal skin temperature, compared with the controls. Thus, the results show that cooling may preserve the reparative capacity in skin subjected to pressure ischemia. It is assumed that this effect is related to a lowered cell metabolism during the ischemia. It may also be concluded that the pressure (mechanical) injury, being the same in both temperature groups, is less important than the ischemic injury.

Animals↗

PubMed1976

Behavioural repertory of cats without cerebral cortex from infancy.

Bilateral removal of the cerebral cortex was made in cats neonatally. Spontaneous and imposed behaviour was studied while they were growing up and after they had become adult. Special emphasis was put on the utilization of visual cues and on learning. The cats ate, drank and groomed themselves adequately. Adequate maternal and female sexual behaviour was observed. They utilized the visual and haptic senses with respect to external space. Two cats were trained to perform visual discrimination if a T-maze. The adequacy of the behaviour of these cats is compared to that of animals with similar lesions made at maturity.

Animals↗

PubMedDate not supplied

Differences in lodgement of tumour cells in muscle and liver.

Differences in the lodgement of circulating tumour cells in various organs are considered an important factor in metastatic organ selection. The present vital microscopic studies show that the pattern of intravascular arrest of tumour cells in muscle after intra-arterial injection is similar to that observed earlier, in the liver, after intraportal injection. However, parallel isotope studies on the lodgement process (at 5 min and 3 h after injection) showed that the tumour cells trapped in the muscle microvasculature were destroyed at a higher rate than in the liver. Tumour cells kept in test tubes, and thus not being subjected to the shearing forces of the circulation, had a higher survival rate than cells trapped in the muscle. The results indicate that stronger retardation forces acting on the tumour cells in muscle (arterial dissemination) than in the liver (venous dissemination) may be one mechanism behind the increased tumour cell destruction in muscle.

Animals↗

PubMedDate not supplied

Migration of human granulocytes in filters: effects of gravity and movable gradients of f-MLP.

The Boyden chamber technique for chemotaxis uses a mesh filter that constitutes a matrix for cell locomotion and, at the same time, creates a local restriction for convective fluid movements that allows the establishment of a diffusive concentration gradient of chemotactic substance in the filter. In the present study, the Boyden chamber was modified by the introduction of a filter sandwich that allowed cell migration both upwards and downwards and by the use of a fluid density gradient controlling cell buoyancy and mechanically supporting a movable chemotactic gradient. This method was used to study chemotaxis and random migration of human granulocytes under the influence of gravitational forces and movable gradients of f-MLP. The results show that gravity affected cell motion significantly during random migration but not during chemotaxis. The rate of chemotactic migration was dependent on the steepness of the spatio-temporal f-MLP gradients. A stationary spatial gradient produced less migration than a gradient that was slowly moved through the filter sandwich in a direction opposite to that of the cell migration. The presence of f-MLP at constant concentration caused a minor, statistically insignificant, increase of the rate of random migration.

Cell Movement↗