Biomedical subjects

J M Zdolsek

Publications and source records attributed to J M Zdolsek.

9 recordsLinked to original sources

PubMed1998

Prevalence of gallstone disease in a Swedish population sample. Relations to occupation, childbirth, health status, life style, medications, and blood lipids.

BACKGROUND: There are only a few Swedish studies on the prevalence of gallstone disease in selected age groups, and none including possible risk factors. METHODS: Of a population sample of 1200 individuals (age, 35-85 years), 857 participated in the study. The study subjects were asked to answer a questionnaire about potential risk factors (occupation, childbirth, life style, and so forth), symptoms, and quality of life. Cholecystectomy had previously been done in 115 subjects, leaving 742 for ultrasound examination of the gallbladder. RESULTS: The prevalence of gallstone disease increased with age, and at 75 years or more, 53% of the women and 32% of the men either had gallstones or had previously undergone cholecystectomy (32% and 13%, respectively). When comparing subjects with and without gallstones, there were no differences with regard to any variable, including blood lipid levels. The odds ratio of previous cholecystectomy was increased in subjects with an occupation requiring no specific education and reduced in subjects using wine or spirits every week. The odds ratio of abdominal pain was increased after previous cholecystectomy. Women in this group also experienced a lower quality of life. CONCLUSIONS: The age and sex distribution of gallstone disease was in the order of the magnitude seen in other Scandinavian countries. None of the studied variables differed between subjects with and without gallstones. Subjects previously operated on with cholecystectomy did worse with regard to symptoms and quality of life.

Adult↗

PubMed1993

Effect of reactive oxygen species on lysosomal membrane integrity. A study on a lysosomal fraction.

Using a lysosome-enriched "light mitochondrial" fraction of a rat liver homogenate, the effects of the reactive oxygen species hydrogen peroxide, superoxide- and hydroxyl radicals were determined. Alterations in the intralysosomal pH and the release of a lysosomal marker enzyme, N-acetyl-glucosaminidase, were used as indicators of changes in the lysosomal membrane integrity. Lipid peroxidation of the fraction was assayed by TBARS measurement. Neither superoxide radicals, generated by hypoxanthine/xanthine oxidase, nor a bolus dose of hydrogen peroxide (0.5-1.5 mM) induced any lysosomal damage. If, however, Fe(III)ADP was included in the superoxide radical-generating system, lysosomal membrane damage was detected, both as an increase in lysosomal pH and as a release of N-acetyl-glucosaminidase, but only after a lag phase of about 7 min. Lipid peroxidation, on the other hand, proceeded gradually. Lysosomes treated with hydrogen peroxide displayed similar dose-dependent alterations, albeit only if both Fe(III)ADP and the reducing amino acid cysteine were added. In the latter system, however, alterations of the lysosomal membrane stability occurred more rapidly, showing a lag phase of only 2 min. Lipid peroxidation, which proceeded faster and displayed no lag phase, levelled out within 10 min. The results indicate that neither superoxide radicals nor hydrogen peroxide are by themselves damaging to lysosomes. Available catalytically active iron in Fe(II) form, however, allows reactions yielding powerful oxidative species--probably hydroxyl radicals formed via Fenton reactions--to take place inducing peroxidation of the lysosomal membranes resulting in dissipation of the proton-gradient and leakage of their enzyme contents.

Animals↗

PubMed1993

Visualization of iron in cultured macrophages: a cytochemical light and electron microscopic study using autometallography.

The objective of this study was to develop a sensitive cytochemical method for the visualization of iron, both at light microscopical (LM) and at electron microscopical (EM) levels, in glutaraldehyde-fixed cultured cells with reasonable morphological preservation. The method is based on autometallography (also called the sulfide silver method or the Timm technique). Gold, silver, and various metal sulfides have previously been shown to act as catalysts for cellular silver deposition from a physical developer (autometallography). In our modification of this cytochemistry, a high pH is used during the initial sulfidation step to guarantee adequate levels of sulfide ions to generate enough Fe(II or III) sulfide. Since this procedure may cause severe cellular distortion, we initially stabilize the cultured cells by a glutaraldehyde fixation. We have compared our new high pH, high S2- LM and EM variety of autometallography with other modifications of this technique that have previously been used for LM and EM demonstration of easily sulfidated heavy metals, such as zinc. Cultured mouse macrophages were examined for the localization of reactive metals following endocytosis of ferritin or inorganic Fe(III) iron. Ag-precipitates, presumed to indicate the presence of iron, were predominantly found within secondary lysosomes of the acidic vacuolar apparatus. The relation of the Ag-precipitates to iron was proven by the fact that iron-exposed cells showed a much reduced amount of silver precipitates after subsequent exposure to deferoxamine a potent iron chelator. Moreover, control macrophages neither exposed to iron nor to ferritin showed only a low normal lysosomal content--and a few extralysosomal sites--of reactive substances, believed to be iron.

Animals↗

PubMed1993

Acridine orange-mediated photodamage to cultured cells.

Photosensitization mediated by the lysosomotropic, weakly basic dye acridine orange (AO) was studied on cultured J-774 cells. The phototoxicity was found to be potentiated by elevated oxygen tension and reduced at low oxygen tension. Moreover, cell cultures pre-exposed to the singlet oxygen scavenger sodium azide showed pronounced protection against the loss of viability induced by AO and blue light. AO-mediated photosensitization was neither increased by pre-exposure of cell cultures to ferric chloride or the catalase-inhibitor aminotriazole nor decreased by exposure to deferoxamine. These observations suggest that type II (singlet oxygen-mediated) reactions predominate over type I reactions (radical-mediated). A rapid and pronounced decrease in lysosomal cathepsin L activity (up to 60%) was observed after an initial 10 min irradiation, indicating the lysosomal compartment to be an early target. This irradiation time did not, however, result in any substantial loss of viability. Levels of cytosolic lactate dehydrogenase were unaffected even after 30 min irradiation, indicating that neither cytosol nor plasma membrane is a primary target of the AO-mediated photodamage. Glutathione depletion by pre-exposure to buthionine-S,R-sulfoximine (BSO) much enhanced the sensitivity of J-774 cells to AO-mediated photosensitization, indicating a protective role for thiol-containing compounds against AO-mediated photodamage.

Acridine Orange↗

PubMed1992

Alloxan cytotoxicity involves lysosomal damage.

The cytotoxic effects of alloxan are not understood in any great detail, although they are considered to involve reactions mediated by oxygen-derived free radicals. These reactive species may form extra-or intracellularly following alloxan reduction, and result in cell damage through a number of complex interactions with a variety of macromolecules. The purpose of the present study was to elucidate further the early intracellular effects of alloxan on a model system of macrophage-like cells in culture. Addition of alloxan (15 mM), without reducing agents, to the medium surrounding the cells (phosphate-buffered saline, PBS, 37 degrees C, pH 7.4) resulted in rapid lysosomal damage (disappearance of the proton gradient over the membrane) followed by severe cellular degeneration (swelling and blebbing) and 50% cell death (trypan blue dye exclusion test) within fifty min. Cells pretreated with the gamma-glutamyl cysteine synthetase-inhibiting agent BSO, to decrease levels of intracellular glutathione, showed enhanced sensitivity to alloxan. The results are interpreted as indicating the cytotoxicity to result from intracellular formation of superoxide radicals, hydrogen peroxide and hydroxyl radicals, the latter within secondary lysosomes containing trace amounts of reactive iron (inducing Fenton reactions). The ensuing lysosomal membrane damage may result in leakage of lysosomal hydrolases and further cellular degeneration.

Alloxan↗

PubMed1991

Effects of alloxan and reducing agents on macrophages in culture.

The diabetogenic effect of the quinonoid compound alloxan is not understood in detail although it supposedly involves reactions mediated by alloxan and oxygen radicals. These reactive species may form extra- or intracellularly and cause cell damage through a variety of complex interactions with several macromolecules. The purpose of this study was to elucidate early (less than or equal to 60 min) effects of alloxan and reducing agents (cysteine and ascorbic acid) on cultured macrophages, as assayed by the trypan blue dye exclusion test and the sensitive fluorescein diacetate and propidium iodide (FDA/PI) double staining technique. During the reactions between alloxan and reducing agents, oxygen was consumed as a sign of superoxide anion radical formation. When alloxan alone was added to two different culture media without serum, oxygen was still consumed, indicating formation of oxygen radicals due to the occurrence of reducing substances in cell culture media. This finding demonstrated the necessity of performing further studies in solutions without reducing capacity, e.g. in phosphate-buffered saline. The experiments showed that exposure of normal and malignant macrophages to alloxan and reducing substances resulted in rapidly occurring plasma membrane damage and ensuing cell death. Separate addition of catalase, desferrioxamine or superoxide dismutase resulted in evident, slight and no protection, respectively. The combinations of (i) catalase and desferrioxamine, and (ii) catalase, desferrioxamine and superoxide dismutase, however, inhibited cell damage in a pronounced and complete way, respectively. The results are interpreted as indicating cell damage due to the extracellular formation of hydrogen peroxide and hydroxyl radicals. The latter in close proximity to the cells and acting on the plasma membrane, while the former, after diffusing into the cell, may have several intracellular targets. The FDA/PI technique proved its value as a quantifiable method for the evaluation not only of cell death but also of cell damage with computer-based fluorometry.

Alloxan↗

PubMed1990

Photooxidative damage to lysosomes of cultured macrophages by acridine orange.

Cultured cells accumulate acridine orange (AO), which is a weak basic dye and a photosensitizer, in lysosomes and other acidic compartments. During exposure to blue light, AO-loaded macrophages show decreasing red granular fluorescence and increasing green diffuse fluorescence. This is hypothesized to represent peroxidative damage to lysosomal membranes resulting in an impaired proton gradient with deprotonation of the AO to its uncharged form and subsequent leakage of the dye. Further damage to the lysosomal membranes will result in release of lytic enzymes from the lysosomal compartment into the cytosol, leading to degeneration and finally cell death. The survival of AO-loaded and light-exposed macrophages is controllable by varying the exposure times to blue light. Inhibition of lysosomal proteases by E-64 results in increased cell survival after AO and blue light-mediated damage, indicating a role of proteolytic enzymes in this type of damage. Morphological analysis shows 'rounding up' with formation of retraction fibrils and pronounced plasma membrane blebbing. The formation of autophagic vacuoles is an early and pronounced event. After protease inhibition, however, all these phenomena are inhibitable to a considerable degree. We have thus directed photooxidative damage selectively to lysosomal membranes and their contents. This technique will allow further detailed studies of the role of lysosomes in degeneration-regeneration processes.

Acridine Orange↗

PubMed1989

Lysosomal enzyme leakage during the hypoxanthine/xanthine oxidase reaction.

Impairment of lysosomal stability due to reactive oxygen species generated during the oxidation of hypoxanthine by xanthine oxidase was studied in rat liver lysosomes isolated in a discontinuous Nycodenz gradient. Production of O2.- and H2O2 during the hypoxanthine/xanthine oxidase reaction occurred for at least 5 min, while lysosomal damage, indicated by the release of N-acetyl-beta-glucosaminidase, occurred within 30 s, there being no further damage to these organelles thereafter. The extent of lysosomal enzyme release increased with increasing xanthine oxidase concentration. Superoxide dismutase and catalase did not prevent lysosomal damage during the hypoxanthine/xanthine oxidase reaction. Lysosomes reduced xanthine oxidase activity, as assessed in terms of O2 consumption, only slightly but substantially inhibited in a competitive manner the O2.- -mediated reduction of cytochrome c. This inhibition was almost completely reversed by potassium cyanide, thus pointing to the presence of a cyanide-sensitive superoxide dismutase in the lysosomal fraction. However, potassium cyanide did not affect the hypoxanthine/xanthine oxidase-mediated lysosomal damage, thus suggesting an inability of the lysosomal superoxide dismutase to protect the organelles. Negligible malondialdehyde formation was observed in the lysosomes either during the hypoxanthine/xanthine oxidase reaction or with different selective experimental approaches known to produce lipid peroxidation in other organelles such as microsomes and mitochondria.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗

PubMedDate not supplied

Mercury induces in vivo and in vitro secretion of interleukin-1 in mice.

Macrophages from SJL and DBA mice incubated with mercuric chloride (HgCl2) in vitro for 24-72 h secreted an increased amount of interleukin 1 (IL-1) to the supernatant compared with control-incubated macrophages, as determined by a sensitive thymocyte proliferation assay. The increase of IL-1 activity showed a highly significant dose-response relationship, being close to that in controls at 10(-8) M, and maximal after incubation with 10(-5)-10(-6) M HgCl2 in both strains. At optimal concentrations of HgCl2 the IL-1 activity started to increase after 6 hrs incubation and reached a maximum after 48 h. Incubation with concentrations of HgCl2 higher than 10(-5) M resulted in a severely reduced IL-1 activity, which correlated with a reduced cell viability. Extracts of HgCl2-incubated macrophages representing cell-bound IL-1 showed no increase in IL-1 activity, irrespective of the concentration or incubation time. Topical application of HgCl2 in a mixture of acetone-olive oil on the external ear of SJL mice induced a dose- and time-dependent increase in IL-1 activity. A maximal increase was seen after application of 1% HgCl2 for 24 h with lower IL-1 activity after 48 and 72 h. Application of 5%, but not 1% or 0.1%, slightly increased the IL-1 activity in the contralateral ear treated with acetone-olive oil only, as compared with the activity in ears from animals given no mercury treatment, suggesting a systemic effect by application of 5% HgCl2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗