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Biomedical subjects

L Olsson

Publications and source records attributed to L Olsson.

At least 163 records · Page 9Linked to original sources
PubMed1978

Effect of tissue specific mitotic inhibitors on survival time of spontaneous and virus-induced murine leukaemia and influence on myocardial degeneration.

Treatment of adult AKR mice with tissue-specific mitotic inhibitor mol. wt. 1,000--20,000 extracted from the AKR thymus significantly delayed the onset of spontaneous thymus leukaemia, whereas extracts of other organs were without effect. A slight prolongation of survival time was found with spleen extract when administered to BALB/c mice infected with Rauscher virus, which causes leukaemia starting in the spleen. Thymus extracts of MW 100,000--300,000 caused myocardial degeneration in some leukaemic and nonleukaemic mice.

Animals↗
PubMed1978

Pharmacologic factors and manipulation of immunity systemic adjuvants in cancer therapy.

Because of the experimental and clinical studies which have been extensively conducted with bacillus Calmette-Guérin (BCG) as a systemic adjuvant in cancer immunotherapy, we have analyzed the main factors and conditions which determine its beneficial action and have underlined some of these (eg, the dose factor which controls the amplification of suppressor cells which is probably responsible for failures and even the possible tumor-enhancing effect of immunotherapy). Knowing those factors and conditions, we have been able to establish a systematic immunopharmacologic study of systemic immunity adjuvants, which has resulted in the discovery of agents whose actions are more rapid than that of BCG on one or a few populations of cells involved in immunity and which, unlike BCG, do not induce suppressor cell amplification. This amplification may explain the difference in the results obtained with this mycobacterium in various clinical immunotherapy trials in which it was applied differently. It is proposed to combine these mono- or pauc-functional adjuvants in order to try to obtain all of the beneficial effects of BCG without the amplification of suppressor cells.

Adjuvants, Immunologic↗
PubMed1978

Experimental induction of tumor growth control by immune adjuvants: current status and some theories to be explored.

Immune adjuvants have been shown to induce tumor growth control in many experimental tumor-host models. The beneficial effect depends on tumor size and type and dose of the adjuvants in question, but few experimental data elucidate, which immunological mechanisms--if any--that are directly involved in the tumor destructive processes induced by immuno-adjuvants. The importance of non-specific tumor immunity is discussed with emphasize on the importance of immuno-competent cells that react non-specifically, and that may include "self-directed" cells. Non-immunological mechanisms are proposed also to be of importance, underlining the possible role of the phenomenon of spontaneous reversion of malignant cells to a non-malignant state. It is finally stressed that both immunologic and non-immunologic properties of immunoadjuvant induced tumor growth control must be analysed before therapy with immunoadjuvants can be optimally applicated in the cancer patient.

Adjuvants, Immunologic↗
PubMed1977

Cellular and humoral immunity to leukemia cells in BCG-induced growth control of a murine leukemia.

The antitumor effects of weekly iv injections of 1.0 mg BCG and/or sc injections of 10(7) irradiated leukemia cells were studied in an isogeneic, transplantable lymphoid leukemia in the C57BL/6 mouse. The injections were started at day 1 after ip inoculation of 10(5) leukemia cells. BCG prolonged the survival time of most animals and cured 22%. BCG plus irradiated cells cured only about 10% of the mice, and irradiated cells alone had no curative effect. Individual tumor-bearing mice in the various experimental groups were examined with respect to ascites tumor cell number; complement-dependent cytotoxic antibodies in sera; direct and antibody-dependent cytotoxicity to tumor cells of lymphoid cells from peritoneal fluid, the spleen, and peripheral lymph nodes; and the cytology of ascites, the spleen, and lymph nodes. Only the antibody-dependent lymphocyte-mediated cytotoxicity (ADLMC) was correlated with the ascites tumor cell number, since the ADLMC was high only in mice with a tumor cell number less than that of the controls. Furthermore, since mice with a low tumor cell number had predominantly only lymphocytes as the nonmalignant cell type in their peritoneal fluid, ADLMC may have had an important role in BCG-induced control of tumor growth.

Animals↗
PubMed1977

Myocardial scintigraphy as a supplementary diagnostic tool in heart disease.

Myocardial scintigraphy with cesium-131 and thallium-201 was performed in 191 patients. Previous myocardial infarctions localized to the anterior and lateral wall of the left ventricle were correctly diagnosed with both radionuclides. Inferior and posterior infarctions were only detected when thallium was used. In patients with non-informative ECG changes like bundle branch block, non-specific ST-T changes or with atypical symptoms, myocardial imaging made an essential contribution to the establishment of a correct diagnosis. The potential value of myocardial imaging in patients with valvular heart disease and in cardiomyopathy is described.

Adolescent↗
PubMed1977

A cytokinetic analysis of bacillus calmette-guérin-induced growth control of a murine leukemia.

The cytokinetics of an isogeneic, transplantable, lymphoid leukemia, growing as an ascitic tumor in the C57BL/6 mouse, has been investigated during normal growth and during regression induced by weekly injections i.v. of 1.0 mg Bacillus Calmette-Guérin (BCG). Survival was significantly prolonged in the BCG-treated group, and 27% of the mice were apparently cured. The tumor growth curves showed, furthermore, that BCG-rreated mice could be divided into two groups according to whether the ascitic tumor cell number was at control level or below that of the controls. By methods such as stathmokinetics, tritiated thymidine autoradiography, and cytophotometry, it was demonstrated that the proliferative activity was higher in BCG mice with a low tumor mass as compared to controls and BCG mice with a tumor mass similar to that of controls. The cytokinetic characteristics of BCG mice with a low ascitic tumor cell number were especially expressed by high mitotic activity, high initial labeling indices, short potential tumor doubling time, and a low number of G0-G1 cells. Furthermore the ascitic tumor cell loss rate was increased in these mice during the whole experimental period. It was deduced from the various parameters and especially from the cytophotometric and autoradiographic results that BCG induces a preferential kill of tumor cells in G0-G1 and the first part of the S phase. In addition, the cytological aspects of the ascitic tumor were found to be related to the cell kinetic pattern as the amount of small and large tumor cells increased and decreased, respectively, with accumulation of tumor cells in G0-G1.

Animals↗
PubMed1975

Chalone-like effect abrogated by dextran sulphate and heparin polyanion pretreatment of target cells.

Chalone prepared from primary BALB/c mouse embryo fibroblasts caused a 33% reduction in incorporation of tritiated thymidine in the cultures of the second in vitro passage of BALB/c embryo fibroblasts, whereas chalone prepared from thymus, skin and spleen was without effect. Pretreatment of BALB/c secondary fibroblasts with the polyanions dextran sulphate and heparin abrogated the chalone effect. The polycations DEAE-dextran and polybrene were without effect. The effect of incubation with the dextran sulphate polyanion was reversed when followed by incubation with DEAE-dextran polycation.

Animals↗
PubMed1975

Studies on the regulation of lymphocyte production in the murine thymus and some effects of a crude thymus extract.

Cell proliferation in the murine thymus was studied in vivo under normal conditions and from 0 to 24 hr after a single injection of a water-soluble extract from mouse thymus, mouse spleen, and mouse skin. The thymus extract reduced during the first 24 hr the mitiotic activity 40%; the spleen extract had a weaker inhibitory effect. The skin extract had no such effect. The thymus extract and spleen extract inhibited the flux of cells into the S phase 0-8 hr after the injection of the extract. Initial labelling index was also reduced in this period. Eight hours after injection of the thymus or spleen extracts the inhibited cells initiated DNA synthesis. The rate of progression of blast cells through the cell cycle was normal 24 hr after the injection of the extracts. It was deduced from the analysis that the thymus extract inhibits processes triggering G0/G1 cells into DNA synthesis, the inhibition of G2 efflux being of minor importance. Finally a model for the regulation of proliferating thymic blast cells and the emigration of small lymphocytes from the thymus is proposed.

Animals↗
PubMed1975

A new preparative method for microspectrophotometric DNA-measurement in megakaryocytes, revealing a significant group of cells with a DNA content of 64 N.

Microspectrophotometric investigations of Feulgen-stained rat bone marrow megakaryocytes, comparing the traditional smear method and a new 1 G sedimentation and 40 degrees C evaporation (S. E.) method, have shown that the latter reveals a significant group of megakaryocytes (ca. 30 percent) with a DNA content of 64 N. This group is totally absent when the smear method is used.

Animals↗