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Biomedical subjects

B Andersson

Publications and source records attributed to B Andersson.

At least 487 records · Page 27Linked to original sources
PubMed1981

The prognosis for patients with cerebrovascular stroke and transient ischemic attacks.

The prognosis for 281 patients with cerebrovascular stroke and 44 patients with TIA is presented. These patients were registered during a prospective epidemiological survey of cerebrovascular diseases in the community of Söderhamn. There was an average population of about 32, 000 during the study period. More than 30% of the stroke patients died during the first 3 months. After 4 years the mortality was about 70% in stroke and 40% in TIA patients. The prognosis was tested towards symptoms and signs. Eleven signs were significantly correlated to adverse outcome in the stroke group, e. g. Babinski's sign present, complete extremity paresis, lowered level of consciousness, fever, tachycardia, anemia and elevated systolic blood pressure. During follow-up at intervals of 1, 2 and 3 years about 60% of the stroke survivors were at home, 20% in old age homes, and 20% in hospitals.

Actuarial Analysis↗
PubMed1980

Lateral heterogeneity in the distribution of chlorophyll-protein complexes of the thylakoid membranes of spinach chloroplasts.

The lateral distribution of the main chlorophyll-protein complexes between appressed and non-appressed thylakoid membranes has been studied. The reaction centre complexes of Photosystems I and II and the light-harvesting complex have been resolved by an SDS-polyacrylamide gel electrophoretic method which permits most of the chlorophyll to remain protein-bound. The analyses were applied to subchloroplast fractions shown to be derived from different thylakoid regions. Stroma thylakoids were separated from grana stacks by centrifugation following chloroplast disruption by press treatment or digitonin. Vesicles derived from the grana partitions were isolated by aqueous polymer two-phase partition. A substantial depletion in the amount of Photosystem I chlorophyll-protein complex and an enrichment in the Photosystem II reaction centre complex and the light-harvesting complex occurrred in the appressed grana partition region. The high enrichment in this fraction compared to grana stack fractions derived from press or digitonin-treatments, suggests that the grana Photosystem I is restricted mainly to the non-appressed grana end membranes and margins, and that the grana partitions possess mainly Photosystem II reaction centre complex and the light-harvesting complex. In contrast, stroma thylakoids are highly enriched in the Photosystem I reaction centre complex. They possess also some 10--20% of the total Photosystem II reaction centre complex and the light-harvesting complex. The ratio of light-harvesting complex to Photosystem II reaction centre complex is rather constant in all subchloroplast fractions suggesting a close association between these complexes. This was not so for the ratio of light-harvesting complex and the Photosystem I reaction centre complex. The lateral heterogeneity in the distribution of the photosystems between appressed and non-appressed membranes must have a profound impact on current understanding of both the distribution of excitation energy and photosynthetic electron transport between the photosystems.

Chlorophyll↗
PubMed1980

Different divalent cation requirements for binding IgM complexes to lymphocytes and macrophages.

We have found that Mg++ supports IgM complex binding to mouse lymphocytes but not to macrophages. In contrast, Ca++ supports IgM complex binding to macrophages but not lymphocytes. IgG complex binding to both lymphocytes and macrophages is divalent cation independent. These findings allow one to distinguish IgG from IgM binding and macrophage from lymphocyte IgM complex binding by their differential divalent cation requirements.

Animals↗
PubMed1980

Leukemic cell versus plasma levels of daunorubicin and daunorubicinol after infusion of daunorubicin as free drug or the DNA complex.

In two patients with acute non-lymphocytic leukemia, leukemic cell as well as plasma concentrations of Daunorubicin (D) and Daunorubicinol (DOH) were studied after administration of D as free drug or as a complex with DNA. The peak plasma concentration of D was slightly higher after infusion of the D-DNA complex than after free drug while the intracellular pattern was the opposite. The intracellulr peak concentrations were found to be 50-100 fold higher and displayed a kinetic pattern which was completely different from that of D in plasma. We therefore suggest that assays of the concentrations of the drug and its toxic metabolite in leukemic cells are more relevant than the monitoring of plasma concentrations in the evaluation of the clinical effect of this drug's action.

Adult↗
PubMed1980

A mechanism for the formation of inside-out membrane vesicles. Preparation of inside-out vesicles from membrane-paired randomized chloroplast lamellae.

Inside-out thylakoid membrane vesicles can be isolated by aqueous polymer two-phase partition of Yeda press-fragmented spinach chloroplasts (Andersson, B. and Akerlund, H.-E. (1978) Biochim. Biophys. Acta 503, 462-472). The mechanism for their formation has been investigated by studying the yield of inside-out vesicles after various treatments of the chloroplasts prior to fragmentation. No inside-out vesicles were isolated during phase partitioning if the chloroplasts had been destacked in a low-salt medium prior to the fragmentation. Only in those cases where the chloroplast lamellae had been stacked by cations of membrane-paired by acidic treatment did we get any yield of inside-out vesicles. Thus, the intrinsic properties of chloroplast thylakoids seem to be such that they seal into right-side out vesicles after disruption unless they are in an appressed state. This favours the following mechanism for the formation of inside-out thylakoids. After press treatment, a ruptured membrane still remains appressed with an adjacent membrane. Resealing of such an appressed membrane pair would result in an inside-out vesicle. If the compartmentation of chloroplast lamellae into appressed grana and unappressed stroma lamellae is preserved by cations before fragmentation, the inside-out vesicles are highly enriched in photosystem II. This indicates a granal origin which is consistent with the proposed model outlined. Inside-out vesicles possessing photosystem I and II properties in approximately equal proportions could be obtained by acid-induced membrane-pairing of chloroplasts which had been destacked and randomized prior to fragmentation. Since this new preparation of inside-out thylakoid vesicles also exposes components derived from the stroma lamellae it complements the previous preparation. It is suggested that fragmentation of paired membrane followed by phase partitioning should be a general method of obtaining inside-out vesicles from membranes of various biological sources.

Cell Fractionation↗
PubMed1980

The outcome of patients with transient ischemic attacks and stroke treated with anticoagulants.

Long-term anticoagulant treatment was given to 25 patients with transient ischemic attacks (TIA) and 49 stroke patients with reversible ischemic neurological deficit or cerebral embolism. Another 16 TIA patients were observed without anticoagulant treatment. Life table analyses, comparing the observed with the expected frequency, revealed increased mortality in the TIA patients irrespective of whether or not they had received anticoagulants. The stroke patients treated with anticoagulants also had a higher mortality than expected. On the other hand, the incidence of subsequent stroke was not higher than expected in the TIA and stroke patients treated with anticoagulants, while it was significantly increased in the TIA patients not treated with anticoagulants. Thus, the risk of stroke, but not the risk of death, was normalized by the anticoagulant treatment. Unacceptably serious bleeding complications were seen in the group of stroke patients with anticoagulant treatment. Bleeding complications, in both TIA and stroke patients, seemed to be related to lengthy treatment, high blood pressure on admission or insufficient patient compliance.

Aged↗
PubMed1980

Demonstration of natural antibodies in normal rabbit serum with similar specificity pattern as mouse natural killer cells.

Normal rabbit sera (NRS) obtained from noninbred animals were shown to contain antibody to YAC-1, a mouse lymphoma, in a complement-dependent 51Cr release assay. A positive correlation was found between the sensitivity to lysis by NRS antibody and the susceptibility to lysis by mouse natural killer (NK) cells when 7 mouse tumors and 1 guinea pig hepatoma were tested in both assay systems. This correlation was further established with a quantitative absorption assay in which NRS was absorbed with various mouse tumors and subsequently tested for cytotoxicity against YAC-1, the most NRS- and NK-sensitive tumor. A striking positive correlation appeared between the capacity to absorb the NRS anti-YAC-1 activity and the NK sensitivity of various mouse tumors to CBA spleen cells. Thymocytes from strain A/Sn mice less than 2 weeks old absorbed a substantial amount of the NRS anti-YAC-1 activity; these cells were also sensitive to mouse NK cytolysis, whereas thymocytes from older mice lacked both properties. These natural rabbit antibodies could not "arm" peripheral blood lymphocytes in the rabbit because 1) the peripheral blood lymphocytes from these animals used as serum donors showed only low cytotoxic activity in an NK assay against NK-sensitive mouse tumors, and 2) no positive correlation appeared between the levels of cytolytic activity and the levels of natural serum antibodies observed in the rabbits. The present data suggest that natural antibodies in NRS showed the same specificity pattern for mouse tumors displayed by mouse NK cells.

Age Factors↗