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Biomedical subjects

J Carlsson

Publications and source records attributed to J Carlsson.

At least 271 records · Page 15Linked to original sources
PubMed1984

Degradation of albumin, haemopexin, haptoglobin and transferrin, by black-pigmented Bacteroides species.

Strains of six black-pigmented Bacteroides species and one un-named strain were examined for their ability to degrade the plasma proteins albumin, haemopexin, haptoglobin and transferrin. Strains of B. gingivalis were most effective, degrading all four plasma proteins at different rates. Strains of B. intermedius and B. asaccharolyticus showed intermediate activities, degrading different individual plasma proteins; strains of B. melaninogenicus, B. loeschei and B. denticola were least active, degrading only haemopexin. These findings are discussed in relation to the availability in tissue fluids of iron for bacterial growth.

Bacteroides↗
PubMed1984

Degradation in vivo of the C3 protein of guinea-pig complement by a pathogenic strain of Bacteroides gingivalis.

The pathogenicity of five black-pigmented strains of Bacteroides was tested in subcutaneously implanted Teflon cages in guinea pigs. The tissue reaction around the cages was registered and the contents of the fluid of the cages were analyzed. Two strains of B. intermedius produced a localized abscess around the cages, while one strain (381) of B. gingivalis and an asaccharolytic strain (BN11a-f) different from B. gingivalis did not induce any signs of abscess formation. One strain (W83) of B. gingivalis caused extensive purulent breakdown of the tissues. When the inoculum of strain W83 contained more than 10(9) cells, the animals were killed. Strain W83 was the only strain that increased in number in the cage. The fluid of cages inoculated with strain W83 was also remarkably different from the fluid of cages inoculated with the other strains. The fluid had a high proteolytic activity. No C3 protein of complement and only traces of immunoglobulins could be detected in the fluid. Both strain W83 and strain 381 had a high proteolytic activity against whole guinea-pig serum and when bacteria of these two strains were incubated with guinea-pig serum for 24 h, almost all serum proteins, including the C3 protein, were degraded. These two strains might thus have similar capacity in perturbing the host defence when inoculated into the tissue cages. The actual difference in pathogenicity between the strains might be explained by a recent finding that the pathogenic strain W83, but not strain 381, requires complement in activating polymorphonuclear leukocytes. The degradation of the C3 protein by the pathogenic strain W83 of B. gingivalis thus may be the crucial event in its perturbation of the host defence. A degradation of the C3 protein by strain 381 would be of no help in eluding the host defence, since this strain activates polymorphonuclear leukocytes in the absence of complement.

Animals↗
PubMed1984

Degradation of the human proteinase inhibitors alpha-1-antitrypsin and alpha-2-macroglobulin by Bacteroides gingivalis.

Various strains of black-pigmented Bacteroides species were grown on horse blood agar and suspended in human serum. After various times of incubation the effect of the bacteria on the serum was evaluated by polyacrylamide gel electrophoresis and "rocket" immunoelectrophoresis. The formation of trichloroacetic acid-soluble material in the suspensions and the capacity of the treated sera to inhibit the activity of trypsin were also determined. The two tested strains of Bacteroides gingivalis (W83, H185) degraded most serum proteins, including the plasma proteinase inhibitors alpha-1-antitrypsin and alpha-2-macroglobulin. They did not, however, degrade alpha-1-antichymotrypsin. Bacteroides intermedius NCTC 9336, Bacteroides asaccharolyticus NCTC 9337, and an asaccharolytic oral strain different from B. gingivalis (BN11a-f) did not degrade the plasma proteinase inhibitors. These strains were, however, able to inactivate the capacity of serum to inhibit the activity of trypsin.

Bacteroides↗
PubMed1984

A wild and an attenuated strain of Francisella tularensis differ in susceptibility to hypochlorous acid: a possible explanation of their different handling by polymorphonuclear leukocytes.

We have previously reported that a wild strain of Francisella tularensis is much less efficiently killed by human polymorphonuclear leukocytes than is an attenuated strain. In the present study, the killing of the attenuated strain was found to be strictly oxygen dependent. The wild and the attenuated strains both induced a respiratory burst in the leukocytes. The difference between the strains in susceptibility to agents produced at the burst could be explained by a difference in susceptibility to hypochlorous acid.

Francisella tularensis↗
PubMed1984

Bactericidal and cytotoxic effects of hypothiocyanite-hydrogen peroxide mixtures.

Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite, a reaction which can protect bacterial and mammalian cells from killing by hydrogen peroxide. The present study demonstrates, however, that lactoperoxidase in the presence of thiocyanate can actually potentiate the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions, such as when hydrogen peroxide is present in the reaction mixtures in excess of thiocyanate. The toxic agent was also formed in the absence of lactoperoxidase in a reaction between hypothiocyanite and hydrogen peroxide. Sulfate, sulfite, cyanate, carbonate, and ammonia, which have been postulated to be formed in the chemical oxidation of hypothiocyanite by hydrogen peroxide, were not bactericidal and did not potentiate the bactericidal effect of hydrogen peroxide. Cyanosulfurous acid, the only other postulated product of the chemical oxidation of hypothiocyanite by hydrogen peroxide, may be the killing agent.

Anti-Bacterial Agents↗
PubMed1984

Demonstration of an extracellular matrix in multicellular tumor spheroids.

Multicellular spheroids of a human glioma cell line (U-118 MG) and a human thyroid cancer cell line ( HTh -7) were analyzed for the presence of extracellular matrix (ECM) using light microscopy, transmission electron microscopy, and indirect immunofluorescence staining for fibronectin, laminin, and collagen. These studies were supplemented by analyses of glycosaminoglycans using autoradiography or chemical methods after metabolic labeling with [35S]sulfate or [3H]glucosamine in conjunction with various extraction procedures. The results showed that both types of spheroids contained an ECM composed of fibronectin, laminin, collagen, and glycosaminoglycans. The organization of the ECM in the spheroids seemed to be similar to that of tumors in vivo. These findings help justify the use of the spheroid system as an in vitro model for the study of biological phenomena of human tumors in vivo. Furthermore, it is concluded that the formation of an ECM in vitro is not confined to normal cells but can be promoted in transformed cells using appropriate culture conditions.

Cell Line↗
PubMed1984

Radiation resistance and the CuZn superoxide dismutase, Mn superoxide dismutase, catalase, and glutathione peroxidase activities of seven human cell lines.

CuZn superoxide dismutase, Mn superoxide dismutase, catalase, and glutathione peroxidase form the primary enzymic defense against toxic oxygen reduction metabolites in cells. To test the importance of these protective enzymes in the cellular radiation response, the enzymic activities of seven different human cell lines were determined in parallel with their clonogenic survival characteristics. A positive correlation between the content of glutathione peroxidase in cell lines and their extrapolation numbers (n) and quasithreshold doses (Dq) was detected. Between the cellular contents of the other enzymes and D0, n, and Dq no positive correlations could be established. An interesting finding was a very high Mn superoxide dismutase content in a malignant mesothelioma cell line P7, which had an extremely high D0, 5.0 Gy.

Catalase↗
PubMed1983

Catalatic activity of lactoperoxidase in the presence of SCN-.

Lactoperoxidase catalyzed the catalatic decomposition of H2O2 in the presence of SCN-. The pH optimum for O2 evolution was 8.5, while the enzyme activity as disclosed by the rate of H2O2 disappearance was optimal at 4.5. Since the catalatic activity of lactoperoxidase was SCN- dependent, and no O2 was evolved, when H2O2 was added to OSCN- in the absence of lactoperoxidase, an enzyme-OSCN complex may be assumed to be an intermediate in the catalatic activity of lactoperoxidase.

Cyanides↗
PubMed1983

Formation and growth of multicellular spheroids of human origin.

Different types of human cells which normally grow as monolayers or suspension cultures were tested for their capacity to form and grow as spheroids. Sixteen out of the 27 tested tumour cell lines formed spheroids. Nearly all of these spheroids also grew. With only two exceptions the doubling times were longer when the tumour cells grew as spheroids than when they grew in conventional mass culture. Eleven out of 13 tested human non-tumour cells formed small spheroids but of these only the spheroids of lymphoid origin could grow. These lymphoid cells grew faster when aggregated to spheroids than when in single-cell suspension culture. None of the other non-tumour cells, which normally grew as monolayers, could grow as spheroids. The normally monolayer-cultured tumour cells formed symmetrical spheroids with smooth surfaces while the normally suspension-cultured cells formed irregular spheroids with rough surfaces. All large spheroids had a necrotic centre surrounded by a shell of viable cells. The thickness of the viable cell layer varied depending on cell type. The shape and organization of cells within the spheroids also varied largely. The results show that many types of human cells can be cultured as spheroids and that a wide spectrum of morphological appearances and growth rates can be obtained.

Cell Aggregation↗
PubMed1983

A method to measure the radio and chemosensitivity of human spheroids.

A method based on the spontaneous outgrowth of cells from spheroids was tested. Different outgrowth patterns were seen depending on the types of spheroids and on the radiation or drug doses. The method allowed dose-effect relations to be determined. Spheroid survival was defined as when the outgrowing monolayers contained at least thousand cells within five weeks. The method was used as an alternative to cloning of isolated single cells. The glioma and osteosarcoma spheroids could not be disintegrated to single cell suspensions since they resisted enzymatic and mechanical treatments for cell separation. Detection of differences in radio and chemosensitivity between different types of spheroids of human origin might be valuable for the understanding of the large variations in therapeutical response often seen between different types of tumors.

Animals↗
PubMed1983

Methodological aspects of microelectrode measurements in cellular spheroids.

Different types of oxygen microelectrodes have been tested in measurements on cellular spheroids. The shape of the oxygen gradients varied strongly depending on size and type of the spheroids. No significant differences in the results were obtained when different types of electrodes were applied. All measurements were made in a perfusion chamber. The shape of the gradients did not vary with time in the perfusion chamber. The reproducibility was found good in repeated measurements using the same spheroid. No mechanical or chemical disturbances were seen during the penetration of the spheroids. Changes in the medium flow rate through the chamber did not drastically change the shape of the oxygen gradients. Almost no convection could be seen at the bottom of the chamber close to the spheroids. The composition of the medium was found to be of importance. Lock's solution containing glucose was found to be satisfactory. The potential signals in the double barrel electrodes allowed an accurate determination of the position when the electrode hit the spheroid surface. The information gained from microelectrode measurements in spheroids might be valuable for the understanding of effects of new tumor treatment modalities in which hypoxic cell sensitizers or high LET radiation are utilized.

Animals↗
PubMed1983

Penetration of substances into tumor tissue: a methodological study with microelectrodes and cellular spheroids.

A new method was tested for studies of penetration of substances into tumorlike tissue. The penetration of the ions K+, Cl-, and Ca2+ through several layers of tumor cells was demonstrated by using double barrelled, ion sensitive microelectrodes with extra thin tip diameters. Spheroids consisting of human glioma, U-118 MG, and human thyroid cancer, HTh-7, cells were used as models of tumor tissue. A microelectrode was inserted into the center of a spheroid. Thereafter, the concentration of the test substance was increased in the surrounding medium. The change in concentration inside the spheroid was recorded and the penetration pattern evaluated. All three types of tested ions penetrated easily through the spheroids. The K+ ions penetrated most efficiently, and the Ca2+ ions showed the slowest penetration. The Ca2+ ions penetrated somewhat more slowly in the U-118 MG spheroids (which had rather small extracellular spaces) than in the HTh-7 spheroids (which had larger extracellular spaces). Ion sensitive electrodes, which are easily available, were used in this study only to demonstrate the principle. We hope that the method described can be used for penetration studies of various substances. For example, all substances that can be detected by enzyme microelectrodes could be studied. The main advantage of the method is that the complete penetration pattern can be studied as a function of time in individual spheroids. Previously described methods require histological procedures for each analyzed penetration time.

Biological Transport↗
PubMed1983

Electro-physiological measurements in cultured cellular spheroids.

Human Glioma U-118 MG and hamster V-79-379A spheroids were used as models of the nodular structure often seen in poorly vascularized regions of solid tumours. K+, Ca2+ activities and membrane potentials were measured in the spheroids, using microelectrodes. Both stable and peak values were obtained. All values were included in the analysis to allow an accurate estimate of the relative number of electro-physiologically active cells at different depths in the spheroids. The relative number of active cells decreased drastically with depth although most cells in the corresponding regions looked morphologically viable. The amplitude values of potentials and K+ activities showed, however, no significant variations with depth. The Ca2+ activity varied largely between individual cells. The relative number of proliferative cells decreased with depth in the spheroids, in parallel to the decrease in the number of electro-physiologically active cells. The results indicate that the fraction of cells, in poorly vascularized regions, having normal metabolism might be fewer than what can be estimated only on a morphological basis. Thus, the amount of cells with the capacity to contribute to growth might be overestimated when inspecting histological sections.

Animals↗
PubMed1983

The detachment, attachment and growth capacity of human glioma and glia cells in culture.

The detachment, attachment and growth were studied in malignant glioma and normal glia cells in culture, using the palladium-agarose cloning method. The number of cells in each individual clone was repeatedly counted throughout 10 days. All four glioma cell-lines studied detached and attached themselves at higher rates than the normal, diploid, glia cells. This dynamic behaviour seemed to be a general property of cultured, malignant, glioma cells. All the cell-lines contained clones with different properties. Some clones were growing, others were nearly constant in cell number and yet others decreased in cell number as a function of time. The differences between these types of clones were surprisingly sharp.

Cell Adhesion↗
PubMed1983

Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide.

Approved type strains of Streptococcus sanguis, S. mitis, S. mutans, and S. salivarius were grown under aerobic and anaerobic conditions. The rate of hydrogen peroxide excretion, oxygen uptake, and acid production from glucose by washed-cell suspensions of these strains were studied, and the levels of enzymes in cell-free extracts which reduced oxygen, hydrogen peroxide, or hypothiocyanite (OSCN-) in the presence of NADH or NADPH were assayed. The effects of lactoperoxidase-thiocyanate-hydrogen peroxide on the rate of acid production and oxygen uptake by intact cells, the activity of glycolytic enzymes in cell-free extracts, and the levels of intracellular glycolytic intermediates were also studied. All strains consumed oxygen in the presence of glucose. S. sanguis, S. mitis, and anaerobically grown S. mutans excreted hydrogen peroxide. There was higher NADH oxidase and NADH peroxidase activity in aerobically grown cells than in anaerobically grown cells. NADPH oxidase activity was low in all species. Acid production, oxygen uptake, and, consequently, hydrogen peroxide excretion were inhibited in all the strains by lactoperoxidase-thiocyanate-hydrogen peroxide. S. sanguis and S. mitis had a higher capacity than S. mutans and S. salivarius to recover from this inhibition. Higher activity in the former strains of an NADH-OSCN oxidoreductase, which converted OSCN- into thiocyanate, explained this difference. The change in levels of intracellular glycolytic intermediates after inhibition of glycolysis by OSCN- and the actual activity of glycolytic enzymes in cell-free extracts in the presence of OSCN- indicated that the primary target of OSCN- in the glycolytic pathway was glyceraldehyde 3-phosphate dehydrogenase.

Depression, Chemical↗