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Biomedical subjects

B Andersson

Publications and source records attributed to B Andersson.

At least 505 records · Page 28Linked to original sources
PubMed1979

Ontogeny of B cells in CBA/N mice. Evidence for a stage of responsiveness to thymus-independent antigens during development.

This paper deals with the CBA/N mice, a strain bearing a genetic defect in their B-cell compartment. By using a previously described system we have been able to show that the immature cells of CBA/N mice are functionally indistinguishable from normal immature cells, in that both can be triggered to respond to thymus-independent (TI) antigens, provided they are supplied with helper T cells. When the maturation is completed, CBA/N B cells are unable to respond to TI antigens (like lipopolysaccharide and polyvinyl pyrrolidine) irrespective of the presence of helper T cells, whereas normal mature B cells have grown able to respond without any help. These data allow us to reject the hypothesis that CBA/N mice are arrested at an immature stage and clearly support the idea that they have deviated during development so that only thymus-dependent B cells develop.

Animals↗
PubMed1979

Isoelectric points of spinach thylakoid membrane surfaces as determined by cross partition.

The isoelectric points of unbroken chloroplast lamellae and various subchloroplast fractions, including a preparation of inside-out thylakoids, have been determined using aqueous two-phase systems containing dextran and charged polyethylene glycol. When the amounts of material in the top phase in a phase system with the positively charged trimethylamino polyethylene glycol are plotted against pH the curve intersects the corresponding curve obtained from phase systems with the negatively charged polyethylene glycol sulfonate. This cross-point can be correlated with the isoelectric point of the material. The cross-point for unbroken chloroplast lamellae was found to be around pH 4.7. Mechanical disintegration lowered the cross-point to around pH 4.4, probably because of exposure of new membrane surfaces. The disintegrated chloroplasts were fractionated by differential centrifugation to separate the grana and stroma lamellae. The stroma lamellae vesicles showed the same isoelectric point as the unbroken lamellae, while a cross-point at pH 4.3 was obtained for the grana-enriched fraction. For thylakoid membranes destacked under low salt conditions the cross-point was 0.3 pH unit lower than for membranes originating exclusively from the stroma lamellae. The most acidic crosspoint (pH 4.1) was observed for the fraction enriched in inside-out granathylakoids. It is suggested that the differences in isoelectric point between various subchloroplast fractions reflect a heterogeneous arrangement of surface charge along and across the thylakoid membrane.

Cell Fractionation↗
PubMed1979

Liquid chromatographic monitoring of daunorubicin and daunorubicinol in plasma from leukemic patients treated with daunorubicin or the daunorubicin-DNA complex.

Fifteen patients with acute nonlymphocytic leukemia have been randomized for treatment with daunorubicin (1.0--1.5 mg/kg) either as the free drug (for 45 min or 4 h) or as the drug bound to a DNA carrier (for 5--6 h). The correlation between plasma kinetics of daunorubicin and its main metabolite daunorubicinol and the different administration schedules of daunorubicin has been studied by reversed-phase liquid chromatography. Plasma concentration kinetics of daunorubicin as well as the daunorubicin-DNA complex was biphasic in character. Maximum plasma level of daunorubicin was found during the infusion period. Its concentration decreased rapidly when the infusion stopped and was below the detection limit of the analytical method 2--4 h later. The data suggests a slower disposition of the duanorubicin-DNA complex compared with the free drug.

Animals↗
PubMed1979

Uptake and distribution of daunorubicin and daunorubicin-DNA complex in mice as studied by whole-body autoradiography and liquid chromatography.

The tissue distribution of daunorubicin (D) and daunorubicin-DNA complex (D-DNA) was studied in mice by means of whole-body autoradiography (WBA) and high-performance liquid chromatography (HPLC). A higher accumulation of radioactivity in the blood after 1 min and a lower initial accumulation in the cardiac muscle were found after administration of 3H-D-DNA than after the infection of free drug. Comparative studies of plasma levels of daunorubicin and daunorubicinol (DOH) in D- and D-DNA-treated animals by HPLC showed that the initial differences were negligible from 2 h onward. A rapid accumulation of D in bone marrow occurred in both D- and D-DNA-treated mice. D reached its maximum level after 1 h and was almost constant for 12 h. A new WBA finding was a rapid and specific accumulation of radioactivity in the pituitary gland, in the thyroid, and in the pancreatic islets, which might be of some interest in consideration of possible late endocrine side effects of anthraquinone glycoside therapy.

Animals↗
PubMed1979

Selection of a low antigenic variant subline from the TA3St ascites carcinoma by repeated passage of antibody-coated cells through anti-immunoglobulin columns.

TA3St mouse ascites carcinoma cells of strain A origin (H-2a) were coated with anti-H-2a serum and passaged through mouse immunoglobulin-anti-immunoglobulin columns repeatedly prior to each in vivo passage. After six passages in vivo, a variant cell line emerged with significantly decreased H-2a expression and an increased ability to grow progressively across H-2 allograft barriers. Chromosome analysis of the variant cell line revealed no major changes in karyotype. The application of the method for studies on the generation of immunoresistant tumor cell variants and on the relationship between antibody-binding sites and rejection target sites is discussed.

Animals↗
PubMed1979

Functional characterization of mouse T lymphocytes with IgM-Fc receptors. I. Studies on ADCC and helper cell function.

The function of mouse T lymphocytes with receptors for IgM-Fc was analyzed by using immunofluorescence and a column separation method. The cellular uptake of FITC-IgM was inhibited with unlabeled Fc5 mu. IgM-FcR+ cells were active in ADCC against IgM-sensitized target cells, but not against IgG-coated target cells. The cells mediating ADCC with IgM antibody were shown to be distinct and physically separable from those mediating ADCC with IgG antibody. Helper T lymphocytes for humoral antibody formation in a hapten-carrier system were shown to be IgM-FcR+ and Fc-IgG-.

Animals↗
PubMed1979

Xenobiotic metabolism by isolated rat small intestinal cells.

A rapid method for isolation of cells from the small intestine of the rat resulted in a preparation where 95--100% of the cells excluded NADH or trypan blue. Isolated intestinal cells catalyzed the cytochrome P-450 dependent metabolism of benzo(a)pyrene, harmine, ethoxyresorufin and ethoxycoumarin. Isolation of intestinal cells 24 hours after a single oral dose of 3-methylcholanthrene resulted in 25--45-fold increases in benzo(a)pyrene, ethoxycoumarin and ethoxyresorufin metabolism, whereas the rate of demethylation of harmine was doubled. Harmine metabolism led to the formation of harmol which was subsequently conjugated with glucuronic acid. Very little sulphate conjugate was detected. Intestinal cells catalyzed glucuronidation of 1- and 2-naphthol at a linear rate for up to one hour. Glucuronidation of 1- and 2-naphthol was saturated at 50 muM, whereas a concentration of 800 muM was necessary for saturation of harmol glucuronidation. Intestinal cells metabolized paracetamol to the glucuronide, sulphate, glutathione and cysteine conjugates. The latter two are evidence of cytochrome-P-450-dependent metabolic activation of paracetamol by intestinal cells.

Acetaminophen↗