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Biomedical subjects

L Hammarström

Publications and source records attributed to L Hammarström.

At least 307 records · Page 17Linked to original sources
PubMed1984

HLA antigens in selective IgA deficiency: distribution in healthy donors and patients with recurrent respiratory tract infections.

HLA-A, B, C and DR typing was performed in healthy IgA deficient donors and in IgA deficient patients with recurrent respiratory tract infections. In healthy donors, a strong association with HLA B8 and DR3 was observed. In the patient group however, no statistically significant association with these antigens could be found. In contrast, an increased frequency of HLA B40 was noted. The preference for HLA B8/DR3 in healthy donors could not be attributed to higher levels of serum immunoglobulins since no major differences in the concentrations of IgM, IgG or the IgG subclasses were seen between the two groups.

Dysgammaglobulinemia↗
PubMed1984

Immunologic evaluation of T chronic lymphocyte leukaemia cells in a patient with a concomitant IgA2 myeloma.

Peripheral blood lymphocytes from a patient with OKT3, OKT4, OKT17 positive T CLL and a concomitant IgA2/lambda myeloma were found to be suppressive in cocultivation experiments and after in vitro preactivation . Although chromosomal analysis after stimulation with T or B cell mitogens suggested a common origin of the two malignancies, T cells did not carry structures recognized by an anti-idiotypic antiserum raised against the purified M-component. Only Fc mu receptors were found on the T cells with conventional rosetting assays, although a weak binding of Latex particles coated with the purified IgA M-component could occasionally be recorded. When purified T cells were submitted to FACS-analysis after incubation with the FITC-conjugated purified M-component, two subsets could easily be distinguished in normal T cells, whereas only the high affinity-binding subset could be found in the patient.

Aged↗
PubMed1984

IgA subclass distribution in paraproteinemias: suggestion of an IgG-IgA subclass switch pattern.

IgA subclass distribution in the serum of 40 patients with IgA multiple myeloma and 10 patients with benign monoclonal gammopathy of the IgA class was determined. All were found to be of the IgA 1 subclass. A review of the literature shows a marked predominance (93%) of IgA 1 paraproteins, suggesting an under-representation of IgA2 myelomas. The subclass pattern in 11 double paraproteinemias studied and those previously reported in the literature suggest a pattern of IgG1 - IgA1, IgA1 - IgG4 and possibly also IgG2 - IgA2 switches in malignant cells.

Humans↗
PubMed1984

Gm allotypes in Finnish myasthenia gravis patients.

Gm phenotype G1m 1,2, and 3 frequencies were examined in 103 Finnish myasthenia gravis patients. There were no significant differences as compared with the expected frequency, either in the total material or when patients were subdivided according to sex, age of onset of disease, thymus pathology, or presence of HLA-B8. However, individuals with Gm(+1) had a significantly higher concentration of antibodies against acetylcholine receptor, possibly indicating a correlation with severity of disease.

Female↗
PubMed1984

IgG subclass distribution of myasthenia gravis thymoma-associated antiskeletal muscle antibodies.

Myasthenia gravis patients with thymoma often have serum antibodies directed against human skeletal muscle. We have developed an enzyme-linked immunosorbent assay to investigate the subclass distribution of these antibodies. Five thymoma patients all had IgG4 antibodies, whereas a patient who developed myasthenia gravis after bone-marrow transplantation had only IgG1 antibodies. The data suggest that IgG1 is the first subclass to appear in the autoantibody response against skeletal muscle.

Autoantibodies↗
PubMed1984

Cell sizes and apposition of dental hard tissues in rats.

The daily apposition of the enamel and dentin and the sizes of ameloblasts and odontoblasts in the first upper molar of 2- to 9-day-old and of 12-day-old rats were examined by light microscopy of freeze-dried sections. The formation of enamel in the first molar started at the age of 2 days and was completed in most of the analyzed areas at the age of 9 days. On each day the enamel on the mesial sides of the cusps was about twice as thick as on the distal sides. The differences in thickness of dentin between the mesial and distal sides of the cusps were not as marked as was seen for the enamel. However, the rapid formation of dentin seemed to continue longer on the mesial sides than on the distal sides. The height of the ameloblasts and odontoblasts showed similar differences between the mesial and distal sides as was seen in the formation of enamel and dentin. In addition, these cells showed a gradual increase and decrease in height during the observation period, with a maximal height in the analyzed area at the age of 4-6 days.

Aging↗
PubMed1984

Alkaline phosphatase activity and tetracycline incorporation during initial orthodontic tooth movement in rats.

The activity of alkaline phosphatase and the incorporation of tetracycline as signs of bone formation were studied after orthodontic tooth movement for 10 h to 6 days in rats. Defined low or high forces were used. A moderate activity of non-specific alkaline phosphatase was found in the periodontal membrane (PDM) in untreated rats and in rats treated with low forces. In addition, all bone surfaces were outlined with a narrow band of intense non-specific alkaline phosphatase activity that was vanadate- and levamisole-resistant. Likewise, tetracycline was incorporated on all bone surfaces. The bone formation rate was low and uniform within the alveolus, indicating that no intra-alveolar drift of the molar occurred in the untreated rats. Orthodontic forces gradually inhibited vanadate- and levamisole-resistant alkaline phosphatases and tetracycline incorporation on the bone surfaces in the pressure zones of the PDM, depending on the magnitude of the force. It was suggested that the disappearance of these isoenzymes, in a limited area, as seen in the pressure zones, was associated with inhibited bone formation and subsequent initiation of bone resorption. On the tension side a slight reduction and redistribution of vanadate- and levamisole-resistant alkaline phosphatase activity could be noted irrespective of the magnitude of the applied force.

Alkaline Phosphatase↗
PubMed1984

IgG subclass distribution of antibodies against S. aureus teichoic acid and alpha-toxin in normal and immunodeficient donors.

IgM, IgG, IgA and IgE class and IgG and IgA subclass levels were determined in 18 IgG2 deficient and six IgG3 deficient donors. IgG2 deficiency was associated with concomitant IgG4, IgA (in particular IgA2) and IgE deficiency. This pattern is compatible with a regulation defect of the downstream switch in the heavy chain locus on chromosome 14. IgG3 subclass deficiency was not associated with further deficiencies. Specific anti-teichoic acid antibodies were lacking in most IgG2 deficient donors supporting the notion that anti-teichoic acid antibodies are normally of this subclass. This was also confirmed in a subclass-specific ELISA using sera from normal donors although substantial amounts of specific IgG1 antibodies were also noted. Two IgG2 deficient donors had normal IgG titres (IgG1 in the subclass specific ELISA) and the lack of IgG1 anti-teichoic acid antibodies in most IgG2 deficient donors may suggest a lack of maturation of the appropriate idiotype. IgG antibodies to alpha-toxin, a pure protein, were within the lower normal range in a large proportion of IgG2 deficient donors but largely normal in the IgG3 deficient donors.

Adolescent↗
PubMed1984

Plasma anti-pneumococcal antibody activity of the IgG class and subclasses in otitis prone children.

Plasma anti-pneumococcal polysaccharide antibody activity (serotypes 3, 6a and 23) was determined in samples from 15 otitis prone children, at 30 months of age, and compared with age matched control children and adults. A recently developed enzyme immunoassay, using IgG subclass specific monoclonal antibodies for analysis of pneumococcal antibody activity of different IgG subclasses was employed. Adult sera always contained the highest antibody concentrations, almost exclusively of the IgG2 subclass. Children, on the other hand, had higher amounts of IgG1, significantly exceeding those of the adults, healthy children having higher IgG1, as well as IgG2 values than otitis prone children. The most significant differences were seen with type 6a, less so with type 23 antibodies. No differences in IgG1 anti-type 3 pneumococcal activity were observed between the children and the adults. These findings support the concept that pneumococcal antibody activity is confined to IgG2 and, in addition, it was found that sera from children contain antibodies of both IgG1 and IgG2 subclasses.

Acute Disease↗
PubMed1983

Chromosomal aberrations in a case of T-cell CLL with concomitant IgA myeloma.

Four consistent markers, involving chromosomes 8, 11, 14, 18, 21 and 22, were found in the majority of metaphases obtained after stimulation of peripheral blood and bone marrow from a patient with a T-cell chronic lymphocytic leukemia (CLL) and a concomitant IgA/lambda myeloma with phytohemagglutinin (PHA), lipopolysaccharide of E. coli (LPS) and S. aureus strain Cowan I bacteria (Cowan). A second malignant clone with three additional markers was observed after stimulation with Concanavalin A (Con A). A chromosome 14 aberration, inv(14) (q11-q32), may be of significance in the T-cell malignancy and may suggest a common clonal origin of the two tumors.

Aged↗
PubMed1983

Histochemistry of enzymes associated with tissue degradation incident to orthodontic tooth movement.

Orthodontic tooth movement in rats was examined by histochemical techniques for some enzymes associated with bone resorption and tissue damage. The maxillary first molar was moved buccally by means of a fixed appliance with predetermined forces for periods of from 10 hours to 6 days. The activities of acid phosphatase and lactate dehydrogenase were higher in cells in the connective tissue of the periodontal membrane (PDM) than in the oral mucosa. A low orthodontic force resulted in an initial redistribution of acid phosphatase-containing cells in the PDM followed by an increased activity of acid phosphatase. The activity of lactate dehydrogenase in the PDM was not affected by low orthodontic forces. The changes in distribution and activity of acid phosphatase and lactate dehydrogenase incident to a high orthodontic force were similar to those seen incident to a low force. However, there was one definite difference. A zone which lacked acid phosphatase activity and lactate dehydrogenase activity developed in the most compressed areas of the PDM. Prostaglandin synthetase activity was found exclusively in the bone marrow and seemed not to be affected by the orthodontic forces. However, some prostaglandin synthetase activity was found in the oral mucosa corresponding to the site of the orthodontic appliance. The adjacent bone surface was covered with cells showing an intense acid phosphatase activity. In the present study the magnitude of the orthodontic force seemed to be a determining factor for the vitality of the PDM but not for the tissue-degradation activity.

Acid Phosphatase↗
PubMed1983

Mitogen-induced switching of immunoglobulin heavy-chain class secretion in chronic B-lymphocytic leukaemia and immunocytoma cell populations.

Lymphocytes from peripheral blood, bone marrow, and lymph nodes from six patients with chronic B-lymphoproliferative disease were studied. Two of the patients had a polymorphic immunocytoma with surface membrane immunoglobulin phenotype mu kappa. Four patients had chronic B-lymphocytic leukaemia (CLL) with the phenotypes mu kappa, mu delta kappa, mu lambda, and mu delta lambda, respectively. In no case did the monoclonal cell populations express gamma chains on the surface, and none produced monoclonal immunoglobulin in vivo. The malignant B lymphocytes were cultured in the presence of polyclonal B-cell activators. Immunoglobulin secretion was detected with the protein A plaque assay and with a modification of the reversed haemolysis-in-agar plaque assay. Immunoglobulin secretion was induced in four of the cell populations. In both the immunocytomas and in one of the CLL cell clones the heat-inactivated Staphylococcus aureus strain Cowan I induced secretion of IgG, as well as IgM, associated only with the same light chain as was expressed on the surface of the unstimulated cells. Thus, mitogens can induce immunoglobulin secretion in vitro in malignant B lymphocytes, and Cowan I bacteria also have the ability to induce a switch of immunoglobulin production from IgM to IgG in a fraction of the leukaemic cell populations.

Adult↗
PubMed1983

Anti-IgA in selective IgA deficiency. In vitro effects and Ig subclass pattern of human anti-IgA.

Anti-IgA antibodies were found in 14 of 33 (42%) IgA-deficient donors. In healthy IgA-deficient blood donors anti-IgA appeared associated with the presence of HLA DR3. The antibodies were mainly of the IgG1 and, in high-titred sera, IgG4 subclasses. Sera containing high-titred anti-IgA selectively impaired IgA synthesis in vitro as induced by direct and indirect polyclonal B-cell activators. These antibodies may play a role in the pathogenesis and/or the maintenance of IgA deficiency.

Antibodies, Anti-Idiotypic↗
PubMed1983

Repair of periodontal tissues in vivo and in vitro.

Repair of experimental cavities in dental roots and of periodontal wounds was studied in vivo and in vitro. Incisors from monkeys were extracted and experimental cavities were made in the roots. The teeth were either replanted immediately or cultured for 1-12 weeks in tissue culture medium. After 8 weeks the tissue reaction around the replanted teeth was evaluated on demineralized histological sections and undecalcified freeze-sections incubated for histochemical demonstration of certain enzymes. The cultured teeth were evaluated on decalcified histological sections. In the experimental cavities of the replanted teeth reparative cementum was found. It was frequently separated from the denuded dentin while a firm attachment was always established to the intermediate cementum and dental cementum at the periphery of the cavities. The reparative cementum was also firmly attached to some small areas on the exposed dentin surface where resorption had taken place. The activity of alkaline and acid phosphatase was lower in the connective tissue in the experimental cavities than in the surrounding PDM, suggesting an incomplete regeneration of the periodontal membrane in these areas. A loose connective tissue devoid of demonstrable collagen fibers was found in the cavities in vitro. The reparative cementum did not fill the experimental cavities in the replanted teeth. The alveolar bone extended into the experimental cavities and made the width of the PDM normal also in the experimental cavities. Epithelial and endothelial cells were numerous in the connective tissue separating the reparative cementum from the alveolar bone in the experimental cavities. It is possible that they contribute to the integrity of the PDM and prevent resorption of the dental root.

Animals↗