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Biomedical subjects

A Larsson

Publications and source records attributed to A Larsson.

At least 307 records · Page 17Linked to original sources
PubMed1991

A functionally active complement system is present in uterine secretion of the mouse prior to implantation.

Sephadex beads were placed carefully in the uterus on days 2 and 3 and left for 6 to 8 h to absorb uterine secretion. The beads were then removed with volatile silicon oil and mounted on small pieces of nitrocellulose paper. Immuno-staining of these bead blots showed they contained the complement components C1q, C3, C4, and C5. We demonstrated that complement component C3 in the uterine secretion could be activated and deposited on model immune complexes, and also that antibody-coated erythrocytes were lysed in utero, that is, a membrane attack complex was produced. Thus, the mouse uterine secretion at the preimplantation stage contains a functionally active complement system.

Animals↗
PubMed1991

Psychological development at 7 years of age in children with congenital hypothyroidism. Timing and dosage of initial treatment.

Sixty of 68 consecutive patients detected during the first two years of the Swedish screening programme for congenital hypothyroidism were Griffiths tested at the age 6.5-7.5 years. The test quotients of the patients could not be distinguished from those of a reference population. Replacement therapy with 8.7 +/- 2.8 micrograms of L-thyroxine (mean +/- SD)/kg/d had been started at 15.0 +/- 7.1 days of life. Furthermore, normal results on Griffiths tests were also found in 13 patients with delayed normalization of serum TSH, i.e. greater than 19 mU/l at the age of six weeks, as well as in patients with retarded skeletal maturity and/or very low neonatal serum levels of thyroxine, i.e. less than 18 nmol/l and tri-iodothyronine, i.e. less than 0.92 nmol/l. Our findings indicate that a replacement dose of 6-11 micrograms L-thyroxine/kg/d is adequate and allows normal psychological development if treatment is started early.

Bone Development↗
PubMed1991

The endothelium in early experimental contact hypersensitivity of the oral mucosa. Leukocyte-binding properties and ultrastructure.

Contact hypersensitivity is characterized by an early and specific diapedesis of mononuclear cells into the site of antigenic challenge. In order to study the functional and ultrastructural properties of the endothelium involved in the recruitment of leukocytes, Sprague-Dawley rats were skin sensitized to DNFB; and this was followed by challenge of the oral mucosa. In vitro binding of peripheral blood mononuclear cells to high endothelial venules in lymph nodes was highly specific but no affinity of peripheral blood mononuclear cells to the vessels was observed in normal oral mucosa or in early contact hypersensitivity. However, 10 days after repeated DNFB challenge, occasional vessels bound overlaid peripheral blood mononuclear cells. Ultrastructurally, we identified migration of mononuclear cells through small venules three h after challenge. The vessels involved, however, did not display morphological signs of activation reminiscent of high endothelial venules in lymph nodes. Mast cell degranulation was evident as early as 30 min after challenge, and a possible mechanism for mast cell-mediated leukocyte recruitment is discussed.

Animals↗
PubMed1991

Immunocytochemical analysis of early focal cellular infiltrates in experimental oral contact hypersensitivity.

The cellular infiltrates of early contact hypersensitivity reactions to 2,4-dinitrofluorobenzene (DNFB) in rat oral mucosa were phenotypically characterized using serial frozen tissue sections and monoclonal antibodies. CD2+CD45RB- lymphocytes and ED1+RT1B/D+ monocytes/macrophages appeared in focal collections at the epithelium-connective tissue interface 2-6 h after challenge with DNFB. These foci also contained CD4+, CD5+, CD8+, TCR alpha beta+ cells. CD45RB+ "naive" T cells were difficult to detect at 2-6 h but appeared in significant numbers at 24 h post-challenge. At this stage, the number of all the other phenotypes also was increased. CD2+ cells were approximately twice as many as CD5+ or TCR alpha beta+ respectively, indicating that TCR gamma delta+ lymphocytes might be involved. An additional observation was the presence of increased numbers of CD2+ lymphocytes in the oral mucosa of sensitized but not challenged animals. Our findings indicate that the oral mucosa of skin DNFB pre-sensitized animals may be "contact hypersensitivity conditioned" by migration-prone memory T cells, and that these cells may rapidly interact with locally resident epithelial Langerhans' cells following antigen restimulation, creating the very initial antigen-specific part of experimental oral contact hypersensitivity.

Animals↗
PubMed1991

Use of chicken antibodies in enzyme immunoassays to avoid interference by rheumatoid factors.

Rheumatoid factor (RF) is a major source of interference in many immunoassays. Most immunoassays use mammalian polyclonal or monoclonal antibodies, and RF can react with IgG from mammalian species, thus causing false-positive results. In this work we have studied RF interference in a sandwich ELISA, where RF in the sample may react with both the capture antibody and the detection antibody to give a false-positive reaction. We show that rheumatoid factors do not react with chicken IgY; if the capture antibody or detection antibody (or both) is of avian origin, the interference of RF or other anti-IgG antibodies in sandwich ELISA can be avoided.

Animals↗
PubMed1991

T-cell receptor V beta haplotype and complement component C5 play no significant role for the resistance to collagen-induced arthritis in the SWR mouse.

The importance of T-cell receptor (TcR) V beta gene haplotype and complement component C5 deficiency for the resistance to collagen-induced arthritis (CIA) in the SWR mouse was studied. Firstly, the immune responses against heterologous and autologous type II collagen (CII) were compared between SWR mice and arthritis-susceptible and major histocompatibility complex (MHC)-identical DBA/1 mice. Secondly, F1 and F2 crosses were made between the two strains and studied for arthritis development, V beta gene usage and C5 presence. After immunization with heterologous rat CII, both strains reacted with a strong autoantibody response. Immunization with mouse CII, on the other hand, gave a much lower response in both strains, with DBA/1 mice having the strongest response. A collection of B-cell hybridomas was created from the draining lymph nodes of SWR mice 9 days after immunization with rat CII. This hybridoma collection showed similarity to previous data from the DBA/1 mouse, by its high frequency of B cells producing IgG specific for CII and with a high degree of cross-reactivity with autologous mouse CII. After immunization with heterologous CII, both T cells specific for heterologous CII as well as T cells cross-reacting with autologous CII could be demonstrated. F1 crosses between SWR and DBA/1 were relatively resistant to CIA (8%), while in the F2 generation 72% of the mice developed arthritis. No correlation between V beta haplotype or C5 and development of arthritis in the F2 mice was found. It is concluded that the resistance to CIA in the SWR mouse is not related to either V beta haplotype or C5 deficiency. Instead we postulate the involvement of two or more genes which are important for the induction and maintenance of tolerance to own CII.

Animals↗
PubMed1990

Chicken IgY: utilizing the evolutionary difference.

Chicken antibodies offer advantages over traditional ones (e.g. rabbit antibodies) due to the evolutionary difference between these immunoglobulins. Chicken give better antibody response against conserved mammalian antigens, they do not react with rheumatoid factors, bacterial or mammalian Fc receptors and can reduce background reactions due to cross-reactivity of anti-IgG antibodies.

Animals↗
PubMed1990

Intrasplenic immunization with minute amounts of antigen.

There are two ways to raise antibodies to minute amounts of immunogen. The first is in-vitro immunization in which the immunogen is presented to a spleen cell culture and about a week later cell fusion for hybridoma production is attempted. The second, and the subject of this review, is intrasplenic immunization, in which the immunogen is deposited into the spleen tissue and the animal itself takes care of growing the spleen cells. Both of these techniques are appropriate when only small amounts of immunogen are available. Intrasplenic immunization, however, requires less laboratory work and there is a decreased risk of contamination, often a problem with hybridoma cultures. The experience of intrasplenic immunization shows that it is the method of choice for immunization with nanogram amounts of immunogen. A successful outcome, however, requires that the immunogen is immobilized on a carrier. This review by Ove Nilsson and Anders Larsson will focus on the various types of matrix which can be used as carriers and on the procedures for transferring these carriers into the spleen tissue.

Animals↗
PubMed1990

Extraosseous and intraosseous oral traumatic neuromas and their association with tooth extraction.

Tooth extraction has been suggested as the most common etiologic factor in the development of oral traumatic neuroma, but intraosseous lesions are stated to be rare. The clinicopathologic features of 45 oral traumatic neuromas are reviewed. Fifteen cases were painful. Inflammatory infiltrate was present in 53% of the painful cases in contrast to only 17% of asymptomatic neuromas, and was the only light microscopic feature significantly related to the incidence of pain. Eleven of 45 cases were found in an intraosseous location. Four of 45 reviewed neuromas were associated with extractions. All 4 cases were painful and 2 of them were in an intraosseous location. Only 3 of the 15 painful cases and 2 of the remaining asymptomatic 30 cases had a tentative clinical diagnosis of traumatic neuroma before removal.

Adolescent↗
PubMed1990

Unusual jaw-bone cysts.

Four cases of unusual types of jaw-bone cysts (paradental, lateral periodontal/botryoid type, sialo-odontogenic, and intraosseous dermoid cyst) are reported. Radiographic and histopathologic features are described. Current literature is reviewed with special attention given to radiographic, histogenetic, and histopathologic aspects of these entities.

Adult↗
PubMed1990

A microELISA useful for determination of protein A-binding monoclonal antibodies.

Affinity chromatography on protein A columns is widely used for the purification of monoclonal antibodies. However, some monoclonal antibodies do not bind protein A. We have developed a sandwich-ELISA for determination of the protein A binding capacity of antibodies. This utilizes microtitre plates coated with protein A, and labeled chicken antibodies for detection of bound antibody. Chicken IgG is one of the few antibodies that does not react with protein A, and can thus be used without the problem of a high background.

Animals↗
PubMed1990

Functional residual capacity in anesthetized children: normal values and values in children with cardiac anomalies.

To assess the increase in functional residual capacity (FRC) with growth, FRC was measured after induction of anesthesia in two groups of children. One group consisted of 74 children, 0.1-11.2 yr of age, without signs of cardiorespiratory disease (referred to here as "normal" children), and the other of 21 children, 0.2-6.9 yr of age, with cardiac malformations. Anesthesia was maintained with halothane in the normal children and with fentanyl, droperidol, and nitrous oxide in the children with cardiac anomalies. All patients were paralyzed, their tracheas intubated, and their lungs mechanically ventilated. FRC was measured with an automated tracer gas washout technique. In 70 patients the measurements were performed in duplicate with a mean coefficient of variation of 2.0%. FRC correlated significantly with height, weight, and age in both groups. Multiple regression analysis for both groups considered together indicated no significant improvement when factors for the sex of the child or for the presence of cardiac anomalies were incorporated into the model. In normal children the simple linear and nonlinear regression equations for FRC (in milliliters) versus height (in centimeters) were: FRC = -529 + 9.48 x height, r = 0.96; and FRC = 0.00175 x height2.66, r = 0.97, respectively. The corresponding equations for FRC (in milliliters) versus weight (in kilograms) were: FRC = -92 + 29.9 x weight, r = 0.93; and FRC = 9.51 x weight1.31, r = 0.95.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Cholesterol synthesis in patients with glutathione deficiency.

3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase catalyses the rate-limiting step in cholesterol synthesis. Glutathione (GSH) has been postulated to be an important activator of HMG-CoA reductase in vivo. HMG-CoA reductase activity was assayed in cultured fibroblasts from healthy children. Solubilized enzyme preparations were prepared by ultracentrifugation after freezing and thawing of fibroblasts. Such treatment increased the relative enzyme activity markedly. Enzymological assay conditions were established. Addition of GSH stimulated the reaction, whereas there was inhibition after addition of glutathione disulphide (GSSG). The inhibitory effect of GSSG could be reversed by the addition of excess GSH. Fibroblast preparations, deficient in GSH, were obtained from children with glutathione synthetase deficiency or from normal subjects after the growth of fibroblasts in the presence of buthionine sulphoximine. Solubilized enzyme preparations from GSH-deficient fibroblasts had HMG-CoA reductase activities lower than or comparable with those of control preparations. The results indicate only some reduction in the capacity for cholesterol synthesis in subjects with glutathione deficiency. The existence of additional activation mechanisms in vivo, alternative to GSH, for thiol-dependent modulation of HMG-CoA reductase activity seems likely.

Buthionine Sulfoximine↗
PubMed1990

Arthritis in DBA/1 mice induced with passively transferred type II collagen immune serum. Immunohistopathology and serum levels of anti-type II collagen auto-antibodies.

Arthritis was induced in DBA/1 mice by passive transfer of syngeneic anti-type II collagen (CII) serum concentrate. After transfer of serum containing 0.2 or 0.5 mg anti-CII auto-antibodies the first clinical signs of arthritis appeared 48 h after injection. Severe clinical arthritis was detected 96 h after injection. Immunohistochemical analyses of joints 48 h after serum injection revealed synovial foci in intercarpal and metacarpophalangeal joints of macrophage-like cells, expressing C3bi-receptors and major histocompatibility complex class II molecules, and infiltration of few CD4+ lymphocytes. Later (96 h after injection), the inflamed synovia were dominated by C3bi-receptor+ polymorphonuclear cells. In contrast to conventionally induced collagen arthritis (CIA), the inflammatory infiltrates, filling joint spaces and synovial tissue, were extensively dominated by polymorphonuclear cells, whereas macrophage-like cells expressing class II molecules and a few T cells were seen only in the periphery of the developing pannus. The anti-CII serum induced arthritis may be used as a model for studies of humoral mediated mechanisms operating in conventionally induced CIA as well as in rheumatoid arthritis.

Animals↗
PubMed1990

Predictive value of quantitative cisternography in normal pressure hydrocephalus.

Twenty-five patients with normal pressure hydrocephalus (NPH) and 16 patients with cerebral atrophy were investigated by quantitative cisternography using anterior images of the head 3, 6 and 24 h after a lumbar injection of 200 MBq 99mTc DTPA (diethylene-triamine-penta-acetic acid). The activity in the lateral ventricles, basal cisterns, hemispheric convexities and total intracranial region was measured. Ratios between these regions/quantities were calculated. Fifteen of the NPH patients improved while 10 were unchanged after ventriculo-peritoneal shunt surgery. The ratio between ventricular and total intracranial activity (V/T) correlated positively with the degree of improvement after shunt surgery. All NPH patients with a V/T ratio higher than 32% improved after the operation but a V/T ratio less than 32% did not exclude the possibility of improvement. With regard to quantitative measurements, the radionuclide cisternography procedure can be reduced to imaging at 24 h.

Aged↗
PubMed1990

Irritant and sensitizing potential of copper, mercury and tin salts in experimental contact stomatitis of rat oral mucosa.

HgCl2, CuSO4, SnCl2, SnCl4 or sodium lauryl sulphate (SLS) were openly applied to rat oral mucosa for 1 min, followed 6 h later by histologic examination of the tissue response. Granulocytes were the predominant inflammatory cells and no lymphocytic infiltration could be seen with any of the substances tested. Irritant threshold levels were defined histologically for each of the substances. CuSO4 was found to be non-irritant at all concentrations. The addition of non-irritant concentrations of SLS lowered the threshold levels for HgCl2 and SnCl2, but CuSO4/SLS was non-irritant at all concentrations tested. Preapplication to the mucosa of SLS at non-irritant concentrations gave results with HgCl2, SnCl2 and CuSO4 similar to those with SLS added to the metal salt solutions. Lesions of allergic contact type could not be induced in the oral mucosa to any of the metal salt preparations.

Animals↗