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Biomedical subjects

W Kayser

Publications and source records attributed to W Kayser.

At least 37 records · Page 2Linked to original sources
PubMed1982

Platelet associated IgG, platelet survival, and platelet sequestration in thrombocytopenic states.

Platelet-associated IgG (PAIgG), platelet mean life span (MLS), and platelet sequestration sites were studied in 69 patients with immune (ITP) and presumed nonimmune thrombocytopenias (NTP). A shortened MLS was associated with elevated PAIgG (N = 46), and with normal PAIgG (N = 15). Four patients had a normal MLS, but elevated PAIgG, four patients were normal for both parameters. The highest PAIgG values occurred in ITP patients with a very short MLS. Nine NTP patients had also elevated PAIgG, but a normal or slightly shortened MLS. There was a significant double log correlation between PAIgG and MLS for ITP, but not for NTP patients. Judged from the coefficient of determination, only 10% of PAIgG were directly related to a shortened MLS. 70% of patients (N = 63) had exclusively splenic and 30% hepatosplenic sequestration. PAIgG was elevated in 29/44 patients with splenic (66%) and in 16/19 patients with hepatosplenic sequestration (84%). In ITP, PAIgG-positive cases were observed in 69% of splenic v 82% of hepatosplenic sequestration, while in NTP the corresponding figures were 6/11 and 2/2. No significant correlation between PAIgG and either sequestration type was demonstrable. We conclude that in immunologically mediated thrombocytopenia only a small portion of PAIgG accounts for a decreased MLS, and that the concentration of PAIgG per se does not determine the platelet sequestration type.

Adolescent↗
PubMed1982

Improved assay for detection of platelet-specific PlA1 antibodies in neonatal alloimmune thrombocytopenia.

A technique is described which permits the detection of platelet-specific, noncomplement-fixing ("blocking') PlA1 antibodies in serologically negative sera of mothers from children suffering from neonatal alloimmune thrombocytopenia. The technique consists of (1) antibody enrichment in eluates prepared from maternal serum and PlA1-positive platelets, and (2) quantitation of antibodies in eluates by the platelet radioactive anti-IgG test. With this assay, PlA1 antibodies were demonstrated in 6 out of 7 maternal sera, and anti-A antibodies in one. It proved valuable also for longitudinal studies for periods up to 30 months after delivery.

ABO Blood-Group System↗
PubMed1981

Complement-fixing platelet autoantibodies in autoimmune thrombocytopenia.

A 16-year-old male patient is described with chronic autoimmune thrombocytopenic purpura and, after two years, "warm" autoimmune hemolytic anemia (Evans syndrome) who transiently developed complement-fixing platelet autoantibodies. The autoreactivity of these antibodies was established by quantitative complement fixation as well as by absorption and elution studies using autologous platelets. We believe this to be the first documented case with this very rare and peculiar type of platelet autoantibody.

Adolescent↗
PubMed1981

A simple method for isolating specific antibodies to complement components.

A simple procedure for isolating specific antibodies to complement components C3, C4 and C5b-9 from whole rabbit antisera or immunoglobin preparations is described. Antisera are first reacted with complement-treated sheep erythrocyte membranes. Immunoglobulins are eluted from the washed membranes with acetic acid at pH 2.4, and further purified by one absorption/desorption step on Protein A Sepharose. The final protein preparations contain greater than 90% rabbit immunoglobins, as assessed by quantitative immunoelectrophoresis and SDS polyacrylamide gel electrophoresis. Binding assays with radioiodinated protein preparations indicate a content of specific antibodies in the range 5-55% of total protein. Since there is virtually no non-specific binding of protein to control cells or membranes, the immunoglobulin preparations are well suited for use in sensitive immunoassays for complement components.

Animals↗
PubMed1980

The clinical significance of platelet-associated IgG: a study on 298 patients with various disorders.

Platelet-associated IgG (PAIgG) was studied by a quantitative platelet radioactive anti-IgG test (PRAT) in 298 patients. At the time of investigation, 171 patients were thrombocytopenic (platelet count < 100 X 10(9)/l), 127 had normal platelet counts. Patients fell into the following disease categories: Idiopathic thrombocytopenic purpura (ITP) (N = 81), possible ITP (19), acute ITP (9), systemic lupus erythematosus (22), autoimmune haemolytic anaemia of warm-type (18), systemic blood disease (65), liver diseases (35), other (49). A significant elevation of PAIgG was found in all disease categories. There was a significant correlation between PAIgG and the reciprocal values of platelet counts for most disease groups. No relationship was discernible between PAIgG and hypergammaglobulinaemic states (serum IgG > 1.8 g/l). Platelet survival studies (N = 30) revealed that normal and increased values of PAIgG were associated with normal or shortened platelet mean life span. It is concluded that an elevated PAIgG is only one of several factors involved in the development of immunologically medicated thrombocytopenia.

Adult↗
PubMed1980

HLA--C antigens on platelets.

The direct demonstration of HLA-C antigens Cw2, Cw-3, and Cw4 on human platelets is described. The antigens were detected by means of a platelet radioimmune anti-IgG test using acid eluates from platelets and lymphocytotoxic antisera. It is concluded that HLA-C determinants are only weakly expressed on platelets. Individual differences observed reflect antigenic variations.

Antibodies, Anti-Idiotypic↗
PubMed1979

[Investigations into the hormonal regulation of the corpus luteum function in the human (author's transl)].

In estradiol micro-crystalline suspension was injected into the ovary containing the corpus luteum in women who underwent hysterectomy. The same complete luteaolysis is in women who did not have hysterectomies was obtained. The conclusion is drawn that the prostaglandins which are formed in the uterus have no influence in man on the regulation of the survival of the corpus luteum. As far as we know to date the high excretion of estradiol from the corpus luteum during the maturation of the corpus luteum forms an internal shuttle mechanisms for the survival of the corpus luteum which inhibits the biosynthesis of progesterone by estrogen and blocks the effect of the gonadatropins on the granulosa cells.

Adult↗
PubMed1979

[Vinblastine-loaded platelets and their effect in a case of idiopathic thrombocytopenic purpura (author's transl)].

The successful treatment of a patient with idiopathic thrombocytopenia (ITP) by vinblastine-loaded platelets (VMT) is described. Serum autoantibodies and platelet-bound IgG disappeared after treatment. We infer that this type of therapy does not oeprate on the level of platelet destroying cells but rather affects antibody producing cells. Since there was also a T-cell sensitization versus VMT we favour the hypothesis of a modified self alteration as the cause of the disease and its recovery of VMT.

Adolescent↗