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O Haferkamp

Publications and source records attributed to O Haferkamp.

At least 19 recordsLinked to original sources
PubMed1992

A fluorescence-microscopic and flow-cytometric study of HeLa cells with an experimentally induced respiratory deficiency.

HeLa cells, cultured over a long period in a medium containing low doses of ethidiumbromide, were used as a model system for flow-cytometric detection of human cells with impaired mitochondrial respiratory function. Based on laserscan and flowcytometric analysis after rhodamine 123 staining, the mitochondrial membrane potential of respiratory deficient cells seems unchanged as compared to control cells. Maintenance of this membrane potential in respiration-impaired cells requires glycolytic ATP generation, as transient inhibition of glycolysis by sodium fluoride affects rhodamine 123 accumulation in ethidiumbromide-treated cells, but not in control cells. We present a protocol which allows the detection and separation of respiratory deficient cells by flow cytometry.

Adenosine Triphosphate↗
PubMed1991

Functional and molecular analysis of mitochondria in thyroid oncocytoma.

We report a functional and molecular analysis of nine oncocytic tumors of the human thyroid. In all the abundance of mitochondria observed ultrastructurally was accompanied by an increase in enzymatic activities of respiratory complexes 1 (NADH dehydrogenase), 11 (succinate dehydrogenase) IV (cytochrome c oxidase), and V (ATPase). Western blot analysis failed to detect uncoupling protein in the tumors. The elevated respiratory enzyme activities were paralleled by an increase in the mitochondrial DNA content. Restriction analysis of mitochondrial DNA gave no indication of heteroplasmy or other gross alterations. We conclude that the mitochondrial proliferation in oncocytic tumors is probably not the result of a compensatory mechanism for the deficiency in enzyme complexes of the mitochondrial respiratory chain.

Adenoma↗
PubMed1991

[Interactions of fluconazole and phagocytic cells].

Fluconazole is a triazole compound with a coefficient of distribution P at pH 7.4 of 1.6 (log P = 0.2), and has thus both hydrophilic and lipophilic properties. The physicochemical and pharmacokinetic profiles of fluconazole are clearly different from those of other azole antimycotics. 3H-labelled fluconazole penetrates very rapidly into granulocytes and monocytes (macrophages) isolated from volunteers. The concentrations of the triazole in the granulocytes are about 28% and in the macrophages about 63% higher than in the extracellular milieu. At the concentrations examined (5, 10 and 20 micrograms ml-1) fluconazole damages cells of Candida albicans which have been phagocytized by granulocytes or by macrophages. A clear synergy between fluconazole and the phagocytes can be demonstrated.

Candida albicans↗
PubMed1990

Flow cytometry as a tool to discriminate respiratory-competent and respiratory-deficient yeast cells.

The cationic lipophilic dye Rhodamine 123 (Rh123) is selectively enriched in mitochondria in a membrane potential-dependent manner. Application of drugs which interfere with the electron flow of the respiratory chain lead to a severe reduction of mitochondrial dye uptake. In this communication we show that the same effect is observed after Rh123-staining of respiratory-deficient yeast mutants. Based on this observation we used flow cytometry to discriminate respiratory-competent and respiratory-deficient yeast cells. Combined with a cell sorter we were able to selectively enrich respiring and non-respiring yeast cells, respectively, from a mixture of cells.

Flow Cytometry↗
PubMed1990

Non-random spatial distribution of intermembraneous particles in red blood cell membrane.

A combined analysis using digital image processing and quantitative evaluation of computed radial distribution of freeze fracture P face particles irradiated and nonirradiated has been carried out. Important quantitative features of the arrangement of particles can be described by computing a statistical measure, the radial distribution function g(r), commonly used to study the structure of liquids. The coordinates for calculating g(r) for each sample were measured automatically by a digital image processing system. The results for the radial distribution function were found to closely resemble g(r) for fluids, indicating the presence of shortrange order. This measure distinguishes three different patterns: i) random distribution, ii) dilute gas like and iii) a liquid like model. The mean number of first nearest neighbours surrounding each particle (coordination number) was found to be of the order of three. The RBC intramembraneous particles are heterogeneous in their behavioural pattern: two thirds random; one fifth, dilute gas; and one tenth, liquid.

Animals↗
PubMed1990

Interaction of fluconazole and human phagocytic cells. Uptake of the antifungal agent and its effects on the survival of ingested fungi in phagocytes.

3H-labelled fluconazole (CAS 86386-73-4) very rapidly penetrated into polymorphonuclear leucocytes (PMNLs) and macrophages (monocytes) isolated from volunteers. The concentration of the antimycotic in the PMNLs was about 28% and in the macrophages even 63% above that in the extracellular medium. At the concentrations examined (5, 10 and 20 micrograms/ml) fluconazole damaged cells of Candida albicans which had been phagocytized by PMNLs or macrophages. There is an evident synergism between therapeutically attainable concentrations of fluconazole and phagocytic cells and this militates against the intracellular survival of the fungus.

Candida albicans↗
PubMed1989

Interaction of azithromycin and human phagocytic cells. Uptake of the antibiotic and the effect on the survival of ingested bacteria in phagocytes.

14C-labeled azithromycin, a new macrolide antibiotic, was accumulated by various phagocytic cells isolated from volunteers or patients. The concentration of the antibiotic in monocytes, polymorphonuclear leucocytes (PMNLs), and alveolar macrophages was greater than that in the surrounding medium by a factor of between 200 and 668. Azithromycin penetrated somewhat more rapidly into PMNLs and monocytes than into alveolar macrophages. On the other hand the final concentration in the alveolar macrophages was greater by a factor of about 3 than that in the other two phagocytic cells. Staphylococcus aureus, Legionella pneumophila and Haemophilus influenzae previously taken up by the phagocytes were rapidly inactivated by low (0.031-0.5 micrograms/ml) concentrations of the antibiotic, which in the presence of the cells were subinhibitory. There is thus a clear synergism between azithromycin and the phagocytic cells which leads to increased intracellular killing of the bacteria.

Azithromycin↗
PubMed1987

[Functions of intrinsic defense against anaerobic bacteria in healthy probands and patients with chronic-septic granulomatosis].

Different strains of Bacteroides fragilis exhibit great differences in sensitivity towards serum from healthy volunteers. In the presence of 10% autologous serum, neutrophilic granulocytes and monocytes (macrophages) caused significant killing of B. fragilis. The measured phagocytic and killing activity of the cells is comparable to their activity against aerobic bacteria (S. aureus). In four patients with chronic granulomatous disease of childhood, phagocytosis was normal but killing of B. fragilis and S. aureus in granulocytes or monocytes (macrophages) was appreciably lowered. This malfunction of the cells was accompanied by a disturbance in oxidative metabolism and inadequate iodination after phagocytosis of B. fragilis. The results suggest that granulocytes and monocytes play an important role in host defense against endogenous infections with anaerobes.

Abscess↗
PubMed1987

Relationships between lymphocyte cholesterol homeostasis and LDL-cholesterol.

The homeostasis of cholesterol was studied in lymphocytes freshly isolated from the blood and cultured with or without low-density lipoprotein (LDL). The content of cholesterol decreased in the lymphocytes cultured without LDL, whereas LDL substituted for cellular cholesterol losses, in spite of almost suppressed LDL-receptor and lymphocyte cholesterol synthesis. Free cholesterol was taken up from LDL mainly via cholesterol exchange and, in contrast to esterified cellular cholesterol, rapidly excreted into the medium. In vitro stimulation of lymphocyte cholesterol synthesis was correlated to the ratio of esterified to free LDL-cholesterol in the blood from which the lymphocytes had been isolated. This result probably reflects the different rates of influx and efflux of esterified or free cholesterol between plasma lipoproteins and lymphocytes. These effects should be taken into account if LDL-cholesterol is determined in plasma for the evaluation of an individual's atherosclerotic risk.

Cells, Cultured↗
PubMed1987

The effect of antibiotics on the intracellular survival of bacteria in human phagocytic cells.

[14C]-labeled josamycin (Wilprafen) readily enters several types of human phagocytic cells-polymorphonuclear leucocytes (PMNLs), adherent monocytes and alveolar macrophages - and is accumulated by these cells to a concentration about 20 times that in the extracellular medium. Similar studies using [14C]-benzyl penicillin revealed that the beta-lactam antibiotic penetrated these cells very poorly. Low concentrations of josamycin and the various phagocytes acted synergistically to inhibit the intracellular proliferation of L. pneumophila or H. influenzae. In contrast, penicillin G was not effective against legionellae ingested by PMNLs, monocytes or alveolar macrophages, even at high concentrations. The uptake of the antibiotics apparently correlates well with its efficacy against the intracellular survival of bacterial pathogens in human phagocytic cells.

Erythrocytes↗
PubMed1985

Morphogenesis and possible precursor lesions of invasive carcinoma of the papilla of Vater: epithelial dysplasia and adenoma.

Surgical specimens from 58 invasive carcinomas of the papilla of Vater were studied histomorphologically. Tubular or villous adenomas, adenomatous residues, and microadenomas were found in the vicinity of the carcinomas in 91.4 per cent of the cases; moderate or severe epithelial dysplasia in adenomatous structures or in surface and ductal epithelium was present in 81 per cent of the cases. The results of the present histomorphologic study support the hypothesis that invasive carcinomas arise from pre-existing mucosal lesions, such as adenoma or dysplasia.

Adenoma↗
PubMed1979

[Prognostic aspects of early gastric carcinoma (author's transl)].

The results of treatment of early gastric carcinoma were analysed in 65 patients. In 33 patients the operation was performed 5 years ago. The 5-year-survival rate was 70%. Prognosis was predominantly influenced by the histology of the tumour. Signet ring cell and anaplastic early carcinomas (diffuse type) had a worse prognosis than intestinal (differentiated) forms. Carcinomas localised wholly in the mucosa had no better prognosis than those penetrating into the submucosa. There is no choice of surgical method according to prognostic criteria as the diagnosis "early gastric carcinoma" can be made only postoperatively from the resection material. Bioptic proof of carcinomatous gastric mucosal changes requires full observation of the rules of cancer surgery.

Biopsy↗