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Biomedical subjects

K Nilsson

Publications and source records attributed to K Nilsson.

At least 433 records · Page 24Linked to original sources
PubMed1976

Characteristic chromosomal abnormalities in biopsies and lymphoid-cell lines from patients with Burkitt and non-Burkitt lymphomas.

The karyotypes of cells from 10 Burkitt lymphoma (BL) biopsies, eight cell lines established from BL and nine cell lines from non-BL sources were studied by chromosome banding techniques. With the exception of the BL-derived cell lines BJAB, GC-BJAB, Maku and U-8691 all biopsies and lines of Burkitt origin contained an extra band at the distal region of the long arm of one chromosome 14. An extra band on chromosome 14 was also found in cells of one non-BL biopsy, in cells from a lymphosarcoma-derived cell line and in a long-established cell line derived from the pleural exudate of a patient with Hodgkin's disease. A distal region at the long arm of one chromosome 8 was missing in all metaphase figures of good technical quality in the same material. The size, morphology and stain-ability of the missing region corresponded fairly well to the extra region at chromosome 14. We therefore suggest that the chromosome 14 marker represents a translocation between chromosomes 8 and 14,t (8q-; 14q+). The translocation was present neither in lymphocytes of the peripheral blood of five Burkitt patients nor in five lymphoblastoid cell lines of non-BL origin. Trisomy 7 was found in two of the 10 BL biopsies, in two BL-derived cell lines, in one non-BL biopsy, in two lymphosarcoma-derived cell lines and in one cell line derived from a patient with Hodgkin's disease.

Burkitt Lymphoma↗
PubMed1976

Independent expression of the two HL-A antigen polypeptide chains.

It is now well established that beta2-microglobulin constitutes one of the two HL-A antigen subunits. In this study support was obtained for the previous notion that the human lymphoma Daudi does not produce beta2-microglobulin (beta2m). Papain-solubilized as well as Nonidet P-40-solubilized Daudi HL-A antigens do not contain any beta2m or any detectable structural analogue of this protein. The chemical and physico-chemical characteristics of highly purified HL-A antigens derived from Daudi cells are indistinguishable from those of the HL-A antigen-carrying polypeptide chain isolated from the P3HRIK cell line. Like P3HRIK-derived HL-A antigens, the HL-A antigens derived from Daudi cells are composed of two identical heavy, alloantigenic polypeptide chains with a molecular weight of about 50 000 each, which are held together by disulfide bridge(s). The HL-A antigens of P3HRIK cells contain, in contrast to Daudi HL-A antigens, two molecules of beta2m. Although no evidence was obtained suggesting any beta2m synthesis in Daudi cells it was apparent that these cells express the HL-A alloantigenic polypeptide chain in amounts similar to those of other cell lines which produce beta2m. The present data suggest [1] that beta2m and the alloantigenic HL-A polypeptide chain are under separate genetic regulation [2], that the cell surface integration of the HL-A antigen-carrying polypeptide chain is independent of the presence of beta2m and [3] that beta2m does not constitute a membrane component absolutely necessary to the integrity of the cell membrane.

Beta-Globulins↗
PubMed1976

Hybridization of a human myeloma permanent cell line with mouse cells.

A population of hybrid cells derived from the fusion of a permanent human myeloma cell line, which secretes complete IgE, and a subline of mouse L cells, did not secrete IgE as evidenced by sensitive immunosorbent tests. Also, the hybrid cells were observed not to contain intracellular IgE (epsilon or lambda chains) in amounts to be detectable by fluorescent antibody techniques. The doubling times and cell cycle parameters of the hybrid cells were found to be similar to those of the slow-growing parental human myeloma cells, in addition, the growth of the hybrid cells was characterized by a higher degree of contact inhibition than the parent mouse cells.

Animals↗
PubMed1976

Expression of immunoglobulin synthesis in human myeloma x non-lymphoid cell heterokaryons: evidence for negative control.

Heterokaryons formed between human myeloma cells and various types of mouse and human non-lymphoid cells loose their cytoplasmic content of lambda light chains, a component of IgE produced by the myeloma parent. This loss of immunoglobulin content was observed regardless of the species origin (mouse or human) of the non-lymphoid partner cell, suggesting that the factors responsible for extinction of this differentiated function are not specific for a species. The kinetics of the loss of immunoglobulin content was essentially identical in the different experiments, since all myeloma X non-lymphoid cell heterokaryons were scored as negative after immunofluorescence staining for lambda chains 4-6 hr after infusion. Myeloma cells treated with inhibitors of protein synthesis (puromycin and cycloheximide) also lost their cytoplasmic content of immunoglobulin after 4 hr. These results indicate that the fusion of myeloma cells with non-lymphoid cells results in an immediate inhibition of immunoglobulin synthesis.

Animals↗
PubMed1976

Short-term tissue culture of two nonsecretory human myelomas. A morphological and functional study.

Bone marrow cells from two patients without detectable monoclonal immunoglobulin (Ig) in serum and urine but with the clinical picture of plasma cell myeloma were cultivated in vitro. Immunofluorescence studies of cultured living and fixed bone marrow cells showed no signs of Ig production in one of the cases, whereas in the other case cytoplasmic kappa chains were detected, which, however, were not expressed at the surface of living cells. Cells from the later patient were also subjected to kinetic, ultrastructural, and functional studies in vitro. The fraction of myeloma cells incorporating tritiated thymidine in vitro decreased gradually during prolonged culture, indicating a continuous cell death. The morphological characterization revealed many similarities between this nonsecretory myeloma and classical myeloma, although the frequency of cells with cisternae of endoplasmic reticulum distended by a granular material was unusually high, as was the frequency of "flaming" myeloma cells. "Flaming" cells were not labeled by tritiated thymidine, suggesting that they are nonproliferative end cells. Studies of the Ig synthesis by gel diffusion analyses of supernatant and cell lysates from [14C]leucine-labeled cultures agreed with the immunofluorescence studies that the myeloma cells were nonsecretory.

Aged↗
PubMed1976

Mg2+- and Ca2+-stimulated ATPase at the outer surface of human peripheral lymphocytes and hematopoietic cell lines. Correlation between enzyme activity and immunoglobulin secretion.

A Mg2+- and Ca2+-dependent ATPase at the outer surface of human peripheral lymphocytes and hematopoietic cell lines has been studied. The enzyme activity varied about 60 fold between the extremes of the cell lines tested. There was no simple relationship between surface-ATPase activity and cell surface area. Nor was the presence of villi or any other morphological characteristic at the cell surface decisive for the degree of surface-ATPase activity. A correlation was, however, found between the ATPase activity and a phenomenon probably involving a contractile process namely immunoglobulin secretion, but it was not possible to establish an interdependence of these cell characteristics.

Adenosine Triphosphatases↗
PubMed1976

Contraction of glycerol extracted fibres of smooth muscle by acetylcholine and imidazole in the presence of a Ca-binding microsomal fraction from rabbit colon.

Microsomal and mitochondrial fractions were isolated from rabbit colon muscle homogenate by differential centrifugation. The calcium content of these fractions were rather similar. The microsomes were divided into subfractions by gradient centrifugation and tested on glycerol treated colon muscle. Acetylcholine and imidazole elicited an EGTA-sensitive contraction of glycerinated colon muscles in the presence of microsomal subfractions and Mg-ATP. The glycerinated colon muscle constitute a rapid system for qualitative drug tests on Ca-metabolism in subcellular fractions of smooth muscle.

Acetylcholine↗
PubMed1976

Surface receptors on human haematopoietic cell lines.

The expression of complement receptors, of Fc receptors, of SRBC receptors and of S-Ig was investigated on human haematopoietic cell lines of proved malignant derivation. According to their origin and to a panel of phenotypic markers these lines have been classified into lymphoma lines, myeloma lines and leukemia lines. Results were compared with those obtained on non-malignant EBV carrying lymphoblastoid cell lines (LCL). Among the lymphoid cell lines the LCL showed a pattern of B-lymphocyte surface markers, i.e. surface immunoglobulins, C3 receptors but low density of Fc receptors. The non-Burkitt lymphoma lines bore in varying degree these B-lymphocyte markers. The lines U-698 M and DG-75 were exceptional in having only surface immunoglobulin. The Burkitt lymphoma lines had all B-lymphocyte markers. The myeloma lines differed from the lymphoid lines in lacking C3 and Fc receptors and showed only trace amounts of surface immunoglobulins. In contrast to lymphoid and myeloma lines, the leukaemia lines were completely lacking surface immunoglobulins, but showed C3 and Fc receptors in variable densities. On line, the ALL derived line MOLT-3 showed the capacity to spontaneous rosette formation with SRBC. The findings that LCL presented a homogeneous pattern of B-lymphocyte surface markers may be of value in order to discriminate between these lines and lines derived from haematopoietic malignancies other than Burkitt lymphomas.

Binding Sites, Antibody↗
PubMed1975

Lectin agglutinability of non-neoplastic and neoplastic human lymphoid cells in vitro.

Agglutination by two lectins, Concanavalin A (Con A) and Ricinus communis agglutinin (RCA), has been investigated in a human lymphoid cell system. The main conclusions of this study are: (1) no systematic correlation exists between the neoplastic state and sensitivity to Con A or RCA; (2) cells of neoplastic lines vary unsystematically in their surface properties as evaluated by Con A agglutination, with the possible exception that presence of Epstein-Barr virus (EBV) is associated with a high degree of agglutination and (3) cells of diploid lymphoblastoid lines and phytohemagglutinin (PHA)-stimulated lymphoctes agglutinate similarly and significantly better than unstimulated T- or B-lymphocytes. The relatively simple Con A agglutination assay can be used as an adjunct in classification of human lymphoid cell lines.

Agglutination↗
PubMed1975

Classification and biological nature of established human hematopoietic cell lines.

Over 200 established human hematopoietic cell lines of normal and malignant origin have been investigated by morphological and functional parameters. Employing morphology as the overriding parameter four types of lines were identified. (1) Lymphoblastoid cell lines, derived from normal and neoplastic hematopoietic tissue, were characterized by the wide morphologic flexibility of individual lymphoblastoid cells, constant association with Epstein-Barr virus (EBV), polyclonal derivation, differentiation for immunoglobulin production (secretion) and their diploids. (2) Lymphoma cell lines. This type of line was established at a high frequency from Burkitt's lymphoma and rarely from other types of lymphoma, but never from patients without malignancy or with non-lymphoma malignancies. Important characteristics were morphologic stereotypia within each line, monoclonal derivation, common but not obligatory association with EBV, variability in the expression of Ig synthesis (no production, or membrane bound Ig, or secretion) and aneuploidy. (3) Myeloma cell lines could only rarely be obtained from patients with myeloma. The basis for classification of these lines is their production of Ig identical to the myeloma protein in vitro. Other important distinguishing features were: plasma cell morphology, absence of EBV and aneuploidy. (4) The leukemia cell line (MOLT 4) was the only line with T-cell characteristics and was easily distinguished from the other types. Important characteristics were a typical surface ultrastructure, absence of EBV and absence of immunoglobulin production, Individual lymphoblastoid lines were in principle identical whereas each line of the other three types had its own characteristic profile. The phenotypic characteristics of the lymphoblastoid lines were very stable during prolonged serial cultivation. Only in a few cases were secondary chromosomal, functional or morphologic alterations noted. We conclude that EBV-carrying lymphoblastoid lines can be obtained from non-neoplastic precursor cells from healthy as well as from diseased individuals. Lymphoma, myeloma and leukemia lines are only obtained from the respective neoplastic tissue but generally at a low frequency. With the exception of Burkitt's lymphoma, malignant hematopoietic tissue and leukemia frequently give rise to established cell lines in vitro of the lymphoblastoid type rather than lines derived from the neoplastic cells;

Antigens, Viral↗
PubMed1975

A human lymphoid cell line with an IgG-like membrane component.

A human lymphoid cell ine (S95) with surface-located IgG is described. The line was derived from a patient with Hodgkin's disease and is aneuploid. Its characteristics are suggestive of a malignant B lymphocyte derivation, but no ultimate proof of malignancy can be forwarded. The line produces immunoglobulin (IgG) which appears to be devoid of light chain. The amount of IgG detectable at the cell surface by inhibition of the rosette formation by protein A-coated sheep red blood cells with protein A was 5-10 ng/10(6) cells corresponding to 70 000 - 140 000 molecules/cell. The immunoglobulin is membrane bound. Partial characterization of the IgG-like protein shows that it has a molecular weight of 50 000 Daltons and that the molecule lacks some of the normal gamma-chain determinants.

Cell Line↗
PubMed1975

Reactivity of smooth-muscle antibodies, surface ultrastructure, and mobility in cells of human hematopoietic cell lines.

Seventeen human hematopoietic cell lines were tested by indirect immunofluorescence (IF) for reactivity with human serum containing smooth-muscle antibodies (SMA). The correlation of the IF pattern to the cell surface ultrastructure was revealed by scanning electron microscopy (SEM). Lymphoma cells, viewed by SEM, had short villi over the entire cell surface, but, by IF, showed a type of membrane fluorescence. Cells of lymphoblastoid lines had thin, long surface villi, sometimes asymmetric but most often distributed over the whole cell surface. Myeloma and leukemia cells, which had few membrane villi but a surface covered by "blebs" as revealed by SEM, demonstrated, by IF, only a few stub-like projections extending from the surface. Time-lapse cinematography revealed that the intensity and pattern of SMA staining were also correlated to the degree of motility. Indirect IF with human SMA-positive serum might be used in the classification of cell lines derived from human hematopoietic tissue.

Antibodies↗
PubMed1975

The effect of methylated oxypurines on the size of newly-synthesized DNA and on the production of chromosome aberrations after UV irradiation in Chinese hamster cells.

A comparison has been made, in Chinese hamster cells, of the ability of various methylated oxypurines to inhibit post-replication repair of DNA after UV irradiation and to potentiate UV-induced chromosome aberrations. DNA synthesized in UV-irradiated cells contains gaps, which are subsequently sealed by a process termed post-replication repair. In rodent cells this process is inhibited by caffeine and its analogues. This has been quantitated by measuring the molecular weight of the DNA synthesized in UV-irradiated cells during a 4-h pulse-labelling period in the presence or absence of inhibitors--the lower molecular weight the greater the inhibition. Eight methylated oxypurines were tested; caffeine and chlorocaffeine were always the most potent inhibitors, tetramethyluric acid was inactive, and the other five derivatives (methoxycaffeine, ethoxycaffeine, paraxanthine, theobromine and theophylline) had intermediate effects. Measurements of the potentiation of UV-induced chromosome aberrations showed that treatments with caffeine or chlorocaffeine again had the greatest effects, tetramethyluric acid and also theophylline had no potentiating activity, and methoxycaffeine was intermediate. This correlation between effects at the molecular and cytological levels is consistent with the hypothesis that the inhibition of post-replication repair by methylated oxypurines gives rise to the increased production of chromosome aberrations.

Animals↗