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Biomedical subjects

B E Christensen

Publications and source records attributed to B E Christensen.

At least 55 records · Page 3Linked to original sources
PubMed1985

Partial Chemical and Physical Characterization of Two Extracellular Polysaccharides Produced by Marine, Periphytic Pseudomonas sp. Strain NCMB 2021.

The marine bacterium Pseudomonas sp. strain NCMB 2021, which can attach to solid, and especially hydrophobic, surfaces, elaborates two different extracellular polysaccharides in batch cultures. One (polysaccharide A) was produced only during exponential growth and contained glucose, galactose, glucuronic acid, and galacturonic acid in a molar ratio of 1.00:0.81:0.42:0.32. It produced viscous solutions, formed gels at high concentrations, and precipitated with several multivalent cations. The other (polysaccharide B) was released at the end of the exponential phase and in the stationary phase. It contained equimolar amounts of N-acetylglucosamine, 2-keto-3-deoxyoctulosonic acid, an unidentified 6-deoxyhexose, and also O-acetyl groups. Despite its high molecular weight (10 to 10 as judged by gel filtration), the polysaccharide produced aqueous solutions with very low viscosities and was also soluble in 90% aqueous phenol, 80% methanol, and 80% ethanol.

Journal Article↗
PubMed1982

E receptor expression of T lymphocytes in T lymphoproliferative diseases.

The lymphoid component of skin infiltrates from 6 cases of mycosis fungoides and 2 cases of T cell chronic lymphatic leukaemia consisted almost exclusively of T lymphocytes with abnormally high E receptor expression. Such T cells were also found to dominate the skin infiltrates from 10 patients with severe atopic dermatitis. Blood T lymphocyte counts from all types of patients were within the normal range, but even the blood T lymphocytes of the patients had a strong E receptor expression. The bone marrow in atopic dermatitis and in mycosis fungoides showed normal T cell counts with normal E receptor expression. Supported by basic lymphocyte-kinetic considerations it is likely that the skin in T lymphoproliferative diseases is characterized by an abnormal ability to home and/or to trap T lymphocytes with strong E receptor expression.

Adult↗
PubMed1981

Quantitation of complement C3b and C3d surface receptors on neoplastic IgM positive B lymphocytes.

C3b and C3d complement receptors on the surface of mononuclear cells from blood, lymph nodes, and spleens were investigated in twenty-nine CLL patients and in eight patients with non-Hodgkin malignant lymphoma. Compared with a normal material, especially the lymphoid tissues but also the blood of the patients contained a high number of C3d receptor positive lymphocytes with a strong expression of C3d receptors per cell. The majority of the cells with high C3d receptor expression also had SmIgM. The number of C3b receptor positive cells was decreased in the patients but the C3b receptor expression per cell was normal.

B-Lymphocytes↗
PubMed1980

Human lymphocyte populations in blood after tetanus vaccination.

The content of circulating T and B lymphocytes in 9 healthy volunteers was estimated before and after secondary vaccination with tetanus toxoid. E, Fc, and C3 receptors were demonstrated by rosette techniques and surface Ig by fluorescence technique. The absolute number of T and non-T (B) lymphocytes was simultaneously increased during the first 48 h and at 144 h after vaccination. The correlation between paired T and non-T (B) lymphocyte counts was enhanced after vaccination, probably reflecting mechanisms governing the traffic of lymphocytes.

Adolescent↗
PubMed1979

The effect of acetyl salicylic acid and dipyridamole on thromboembolic complications in splenectomized patients with myelofibrosis.

The effect of combined treatment with acetyl salicylic acid and dipyridamole on thrombic phenomena was studied in splenectomized patients with an aggressive form of myelofibrosis. 3 of these patients had thrombotic episodes, shortened platelet survival and an abnormal platelet aggregation pattern. The treatment with antiplatelet drugs resulted in a decreased platelet utilization as evidenced by clinical improvement and an increasing platelet concentration.

Aged↗
PubMed1978

Traffic of T and B lymphocytes in the normal spleen.

The occurrence of C3b and C3d complement receptors and of Fc and E receptors in normal splenic tissue was studied in cryostat sections incubated with specific marker cells. Thereby the topographic distribution of T and B lymphocytes in the splenic tissue was mapped: Te lymphocytes are found especially in the periateriolar sheaths, B lymphocytes in eccentric zones around the arterioles. The cells in the splenic pulp carry especially Fc, but also C3b receptors, whereas C3d receptors appear to be specific of lymphocytes. The basic lymphocyte traffic behind the mapped distribution of the lymphocyte subpopulations in the spleen was elucidated by lymphocyte kinetic studies using autologous 51Cr-labelled reinfused lymphocytes. These studies were performed partly on normal persons and partly on splenectomized persons without immune defects. The results indicate the presence of an exchangeable pool of T as well as of B lymphocytes in the spleen, the T cell pool being larger and making up in normals about 30% of the total exchangeable T lymphocyte mass. The matrix for the T lymphocyte pool in the spleen is the periateriolar sheaths. The difference in structure between the lymph nodes and the lymphoid tissue of the spleen, including differences in the distribution of lymphocyte subpopulations, are explained by the special vascular arrangement in the spleen.

Adult↗
PubMed1977

Splenectomy in chronic lymphocytic leukaemia.

In a retrospective study it was endeavoured to evaluate the effects of splenectomy in chronic lymphocytic leukaemia (CLL) characterised by splenomegaly. The material comprises 42 patients subjected to the operation in the course of the past 20 years. In the majority the spleen weighed more than 1000 g. The main indication for splenectomy was anaemia, while in 9 cases it was thrombocytopenia and in 14 cases hypercatabolism. Splenectomy is followed by a pronounced increase in the venous haemoglobin level and platelet count to higher values which have been recorded for up to 3 years after the procedure. In cases where data were available, there has been weight gain and a falling basal metabolic rate. Splenectomy is effective especially in cases predominated exclusively by splenomegaly, but even in cases with marked extrasplenic manifestations, splenectomy often greatly reduces the need for prednisone and cytostatics. Increasing hepatomegaly and lymphomas were not more common after splenectomy than in a control series, and the incidence of infections was not increased after the operation. For comparison, 37 non-splenectomised patients with splenomegaly were assessed. X-radiation of the spleen seems to be insufficient, since usually it has to be repeated. Splenomegaly does not decrease spontaneously and rarely after treatment with prednisone/cytostatics. The findings indicate that splenectomy of patients with CLL and increasing splenomegaly should be performed more often and presumably also earlier than recommended in the literature.

Adrenal Cortex Hormones↗
PubMed1977

Semiquantitative determination of Cc and C3 receptors on human lymphocytes by isotope-labelled marker cells.

The number of Fc and C3 receptors on normal B lymphocytes, isolated from blood, was assessed semiquantitatively by a new method in which the marker cells (pretreated sheep erythrocytes) for Fc and C3 receptors are labelled by 99Tc and 51Cr respectively. The mean number of bound marker cells per rosette was assessed simultaneously by measurements of radioactivity. Control studies showed that a measuring system using 1/4 agglutinating titre of antibody on the marker cells is particularly advantageous: (1) Fc and C3 receptors are not demonstrable on T lymphocytes; thus, B lymphocyte fractions with Fc and/or C3 receptors are well-defined. (2) The binding affinity of the marker cells for normal lymphocytes is so weak that the number of bound marker cells per rosette rarely reaches the maximum which was calculated and measured as about 30 marker cells per rosette; thus, the measuring system is sensitive to changes in the number of receptors. (3) By binding of marker cells to lymphocytes bearing Fc as well as C3 receptors it has been demonstrated that interference phenomena between the two marker cells are not operative. Studies of blood lymphocytes from normal human subjects showed B lymphocytes carrying either Fc and C3 receptors as well as a fraction of B lymphocytes having both Fc and C3 receptors. The latter maker up about 6% of the lymphocyte mass. Comparative assessment of the quantitative distribution of these receptors indicates a developmental sequence, B lymphocyte with Fc receptors evidently developing, via B lymphocytes with Fc as well as C3 receptors, into B lymphocytes having C3 receptors only.

Adult↗