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Biomedical subjects

M Madsen

Publications and source records attributed to M Madsen.

At least 235 records · Page 13Linked to original sources
PubMed1980

Isolation of human T and B lymphocytes by E-rosette gradient centrifugation. Characterization of the isolated subpopulations.

Some methodological aspects of E-rosette gradient centrifugation for separation of human B and T lymphocytes are described. Treatment of sheep red blood cells (SRBC) with 2-aminoethylisothiouronium bromide (AET) accelerates and enhances E-rosette formation providing an effective and time saving method which takes less than 2 h to perform. Depletion of E-rosette forming cells (E-RFC) is almost complete, leaving less than 1% of the initial E-RFC at the interphase layer. By use of the lymphocyte donor's autologous serum containing naturally occurring anti-SRBC antibody and complement the SRBC in the rosetted T lymphocyte fraction are easily and completely lysed without damage to the lymphocytes. This procedure is shown to have little effect on the properties of the isolated T cells. The isolated lymphocyte subpopulations have been characterized by tests for lymphocyte and monocyte markers.

B-Lymphocytes↗
PubMed1980

Histological and immunopathological studies in a case of chronic Epstein-Barr virus infection terminating in a Burkitt-like lymphoma.

A 6-year-old boy suffered from a severe lymphadenopathy, characterized histologically by a fulminant polyclonal immunoblast proliferation simulating malignant lymphoma with many immunoblasts resembling Reed-Sternberg cells. He had no history of infectious mononucleosis but Epstein-Barr virus (EBV) infection was evident from serological findings, and EBV-associated nuclear antigen (EBNA) was demonstrated in a high percentage of lymphocytes of blood and lymph nodes. An adequate humoral response to EBV ruled out the possibility of an X-linked recessive lymphoproliferative syndrome as the underlying cause of chronic EBV infection. A chromosomal defect in a subpopulation of lymphocytes was induced by interferon and might somehow be associated with a subtle immunodeficiency of our patient. After exacerbation of the disease chemotherapy was included in the treatment but the patient died 9 months after the onset of the disease. At autopsy the lymphoblastic cell proliferation had changed from that of immunoblasts to cells resembling the Burkitt's lymphoma cells. A change of the proliferating cell type was supported by means of cytochemical and immunological cell markers. The presence of EBV in these cells was demonstrated with the EBNA technique. It is concluded that our case may well support the hypothesis, that EBV may induce lymphoma-like polyclonal immunoblast proliferation in immunodeficient individuals, and that occasionally a monoclonal proliferation of the Burkitt's lymphoma type may supervene.

Biopsy↗
PubMed1980

Lymphocyte subpopulations in man: characterization of in vivo-educated, alloreactive, cytotoxic lymphocytes.

Alloreactive cytotoxic lymphocytes present in peripheral blood of two normal humans have been studied by rosette fractionation experiments. It is shown that the effector cells, have receptors for SRBC, low avidity FcR, are nylon non-adherent and without CR. These results reveal a phenotype of membrane markers which is very much like the phenotypes of the major part of K cells, NK cells and the effector cells in mitogen induced cell-mediated cytotoxicity, indicating a common ancestor in the immune system. From a functional point of view all these cytotoxic effector cells may be T cells, some specific others non specific, in parallel to T helper and suppressor lymphocytes.

Adult↗
PubMed1980

Urinary estrogen excretion and concentration of serum human placental lactogen in pregnancies following legally induced abortion.

Feto-placental function was assessed by 24-hour excretion of estrogen in urine and by the concentration of human Placental Lactogen (hPL) in serum in pregnant women whose previous pregnancy was terminated by legally induced abortion. The mean 24-hour excretion of estrogens in urine and the mean concentration of hPL in serum were no lower in this group than in women without previous induced abortion. Neither was the frequency of a low 24-hour excretion of estrogens in urine or low concentration of hPL in serum (values less than mean - 1.96 s) found to be increased. This study could not demonstrate an increased frequency of dysfunction of the feto-placental unit during the last part of pregnancy in women with previous legally induced abortion. These findings indicate that legal abortion does not seem to increase the frequency of retarded intrauterine growth in a subsequent pregnancy.

Abortion, Legal↗
PubMed1979

A methodological study of E-rosette formation using AET-treated sheep red blood cells.

The influence of some of the well knwon technical variables on the E-rosette technique was examined using sheep red blood cells (SRBC) treated with 2-aminoethylisothiouronium bromide (AET). With AET treatment, E-rosette formation becomes less dependent on time and temperature and on the presence of serum. The mechanical stability of the rosettes is enhanced, and the number of SRBC attached to each rosette-forming lymphocyte (RFC) is markedly increased, leading to a sharper distinction between RFC and non-RFC. Ultimately, significantly more E-receptor carrying lymphocytes become detectable. Evidence is provided that the specificity of the E-rosette technique is unchanged after AET treatment of SRBC, in spite of the enhanced binding. A simple and reliable method for E-RFC identification is documented.

Animals↗
PubMed1979

Lymphocyte subpopulations in man: B-cell stimulation induced by pokeweed mitogen and irradiated T cells.

The enhanced stimulation of human B lymphocytes by pokeweed mitogen in the presence of irradiated T helper lymphocytes has been studied, revealing that the proliferative responses measured by incorporation of thymidine in cultures of B lymphocytes and irradiated T lymphocytes in a 1:2 or 1:4 ratio is mostly a function of the B cells. Only a minimal number, if any, of the T cells contaminating the B cell suspensions is stimulated to proliferation. This is in contrast to stimulation of the B-cell suspensions without addition of irradiated T cells, where both B cells and T cells proliferate. The irradiated T helper cells have no FcR for antigen-bound IgG, and as well allogeneic as autologous T cells exhibit helper capacity of equal strength. The test system described makes it possible selectively to test one B-cell function and the corresponding T helper capacity.

B-Lymphocytes↗
PubMed1979

Lymphocyte subpopulations in man: suppression of PWM-induced B-cell proliferation by infectious mononucleosis T cells.

The in vitro polyclonal pokeweed mitogen (PWM)-induced activation of human B lymphocytes is enhanced by addition of autologous or allogeneic irradiated T cells. This model for B/T-cell cooperation may be used to define and describe the balance between T helper and T suppressor phenomena. The present study investigates the helper and suppressor capacities of mononuclear cells isolated from peripheral blood of infectious mononucleosis patients during the acute disease and the reconvalescence period. During the acute disease we found a functional lack of T helper capacity; furthermore, the T cells were able to suppress the PWM and T-cell-dependent B-cell proliferation of healthy donor cells. The suppression was non-cytotoxic; i.e. not due to destruction of the responder cells. This phenomenon of non-cytotoxic suppression was found for all seven patients studied and disappeared during the reconvalescence period, indicating that the T lymphocytosis seen in infectious mononucleosis includes an expansion of T suppressor cells.

Adolescent↗
PubMed1979

Lymphocyte subpopulations in man: relationship between four subpopulations identified by membrane markers.

The interrelationship between four subpopulations of human lymphocytes was studied in eight normal persons. Double marking and fractionation experiments established that lymphocytes with receptors for AET-treated sheep erythrocytes constitute a population complementary to cells that carry surface membrane immunoglobulins as they are identified by polyvalent rabbit anti-human immunoglobulin; the latter includes nearly all cells with complement receptors. Two functionally different receptors for antigen-bound IgG are identified by their binding avidity for rabbit-antibody-sensitized ox erythrocytes, defining populations of lymphocytes with high-avidity and low-avidity receptors, indicating two valuable differentiation markers.

Antibody Affinity↗
PubMed1979

Lymphocyte subpopulations in man: characterization of human killer cells against allogeneic targets sensitized with HLA antibodies.

Human killer cells mediating antibody-dependent cytotoxicity against allogeneic lymphoblasts presensitized with HLA antibodies have been studied by rosette fractionation experiments. Enriched and/or depleted cell suspensions have been tested in dose-response studies. Two different populations can act as killer cells. The major cytotoxic capacity is retained among T cells with high-avidity Fc receptors, whereas a minor cytotoxic capacity was found among non-T cells with high-avidity Fc receptors. These two populations have different dose-response curves, indicating different effector mechanisms.

Cytotoxicity Tests, Immunologic↗
PubMed1979

False negative HLA-DR assignment necrokidney donors. A glucocorticoid effect?

Thirteen potential necrokidney donors were HLA-DR typed using peripheral blood B lymphocytes (PBBL). Antigen assignment was impossible in 10 cases because of non-reactivity of the PBBL with the HLA-DR testserum set, in some of the cases in spite of positive reactions with a positive control xenogeneic anti-human B cell antiserum. In five of these 10 donors, HLA-DR typing was also performed on B lymphocytes isolated from the spleens, and in all five cases strong specific reactions were obtained, allowing reliable antigen assignment. Evidence is provided that the negative serum reactions with the five donors' PBBL were "falsely negative". It is suggested that glucocorticoid treatment prior to blood sampling for HLA-DR typing may be responsible for the phenomenon.

Adolescent↗
PubMed1979

HLA--DR typing of frozen B lymphocytes.

In the complement dependent lymphocytotoxic microtechnique it was found that antibody-killed frozen B lymphocytes are sufficiently stained for reliable reading after 30 min of incubation with trypan blue, while the background of staining is only about 10%. During the next 30 min of incubation, however, the background of staining increases to about 30%, whereafter it remains constant for at least 24 h. Formaldehyde is able to stop the trypan blue uptake by killed or damaged lymphocytes completely. Consequently, if formaldehyde is added to the reactions 30 min after the trypan blue addition, the otherwise rapidly increasing background of staining is kept at an acceptable level of 10%, thus making HLA-DR typing of frozen stored B lymphocytes possible. The trypan blue staining seems rather independent of incubation conditions before the addition of the dye. Similar results were obtained with T lymphocytes.

B-Lymphocytes↗
PubMed1979

B-prolymphocytic leukaemia--a mantle zone lymphoma?

A case of prolymphocytic lymphoma/leukaemia (PL) sensu Galton in a 32-year-old man is presented. The leucocyte count was 19.0 x 10(9)/1 at presentation and tartrate resistent acid phosphatase was present in most prolymphocytes. Immunological investigation of prolymphocytes from lymph nodes, spleen and peripheral blood revealed the surface marker phenotype: SmIg + (mu, (delta), lambda), IgG-Fc-receptor +, C3-receptor +. The prolymphocytes from lymph nodes and spleen were C3-receptor + in a high percentage, while only a few were IgG-Fc-receptor +. This proportion was reversed in the blood prolymphocytes. The histology of lymph nodes was unique and strongly suggested a preferential involvement (homing phenomenon) of the mantle zone of the lymphatic follicle. These results may indicate that emission of prolymphocytes from lymph nodes to circulation involves a change of surface receptors. It is finally suggested to consider the diagnosis of not only hairy-cell leukaemia but also PL in the case of tartrate resistent acid phosphatase-positive lymphoma/leukaemia.

Acid Phosphatase↗