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Biomedical subjects

C Fuhrmann

Publications and source records attributed to C Fuhrmann.

At least 37 records · Page 2Linked to original sources
PubMed1997

Detection of vital germ cell tumor cells in short-term cell cultures of primary tumors and of retroperitoneal metastasis--clinical implications.

By establishing short-term cell cultures derived from retroperitoneal metastasis after neoadjuvant chemotherapy, our aim was to improve the diagnosis and prognosis in patients with advanced testicular germ cell tumors. The histological evaluation of surgically removed metastatic tissue by retroperitoneal lymphadenectomy (RLA) is extremely complicated after previous chemotherapy, but knowledge of persistence of vital tumor cells in residual lesions is of great prognostic value and therapeutic consequence in patients with testicular germ cell tumors. We therefore investigated whether vital tumor tissue could be detected in short-term cell cultures derived from such metastatic lesions by measuring the concentration of the tumor markers beta human chorionic gonadotropin (beta HCG) and alpha-1 fetoprotein (AFP) in cell culture supernatants. We initially demonstrated the specificity of the determination in cell cultures of human transitional-cell carcinoma cell lines, human foreskin fibroblasts and normal testicular tissue. In a group of 20 patients with untreated primary testicular germ cell tumors, detection of beta HCG and AFP was increased about threefold in cell culture supernatants in comparison to the serum concentration. Finally, we prepared primary cell cultures from surgically removed retroperitoneal metastasis of 12 patients with testicular germ cell tumors after chemotherapy. The serum concentrations of beta HCG and AFP of all patients were at normal values when RLA was performed. However, pathologically increased concentrations of beta HCG (3/3) and AFP (2/3) in cell culture supernatants were found in 3 of 12 cell cultures. Interestingly, these three patients with a pathological increase in beta HCG and AFP as determined in the supernatant of the short-term cell cultures had tumor progression within a mean follow-up of 3 +/- 1 months (P < 0.01), whereas 9 of 12 patients who had no pathological increase in beta HCG and AFP as determined in the supernatant of the short-term cell culture were in complete remission (CR) after a mean follow-up of 40 +/- 11.6 months.

Adult↗
PubMed1997

Studies on the rod-coccus life cycle of Rhodococcus equi.

In the present study all 19 Rhodococcus equi cultures isolated from horses and 19 of 22 R. equi cultures isolated from human patients displayed a rod-coccus life cycle after cultivation under defined growth conditions. A bacillary growth could be observed after cultivation of the bacteria in fluid media for 4 h at 37 degrees C, a coccoid morphology after cultivation of the bacteria for 24 h either on sheep blood agar plates or in fluid media. The different morphological features did not significantly influence the typability of the bacteria or the expression of surface proteins including 15-17 kDa virulence proteins. Studies on further surface characteristics revealed a relation between haemagglutinating properties, the surface hydrophobicity and adherence properties of the bacteria to HeLa cells. These properties seemed to be influenced by the cultivation conditions but not by the different morphological forms of the bacteria. A haemagglutination reaction, a hydrophobic surface and an enhanced adherence to HeLa cells could be observed with coccoid bacteria after cultivation in fluid media for 24 h at 37 degrees C but not with coccoid bacteria harvested from sheep blood agar plates or with bacillary bacteria after 4 h growth in fluid media. This difference might possibly be caused by the degree of encapsulation of the bacteria after various cultivation conditions and a subsequent masking effect of the hydrophilic polysaccharide capsule of R. equi.

AIDS-Related Opportunistic Infections↗
PubMed1997

Correlation of radiation-induced micronucleus frequency with clonogenic survival in cells of one diploid and two tetraploid murine tumor cell lines of the same origin.

Whether the micronucleus assay can be used as a predictive tool to estimate the intrinsic cellular radiosensitivity depends on whether the results correlate with clonogenic survival. In the present study we investigated the influence of the ploidy on the correlation of the two assays by comparing cells of one diploid and two tetraploid murine tumor cell lines of different radiosensitivities. A definite correlation between survival and micronucleus frequency is evident for all three cell lines investigated. The rank order of the frequency of micronucleus expression correlates with that of clonogenic survival in the cell lines studied. No influence of DNA content on the radiosensitivity and the relationship between the micronucleus frequency and clonogenic survival could be observed. Thus our results are promising for the clinical application of the micronucleus assay as a predictive measure of radiosensitivity. However, it is necessary to consider such factors such as cell proliferation kinetics which may influence the correlation between micronucleus frequency and clonogenic survival.

Animals↗
PubMed1997

[Characterization of Rhodococcus equi isolates from horse and man].

In the present investigation 19 and 22 R. equi-cultures isolated from diseased horses and humans, respectively, could be correctly identified by their morphological, biochemical and serological properties. The rod-coccus life cycle appeared to be a common feature of almost all cultures investigated. The cultures were typeable with the typing system described by Prescott (1981). The predominant serotypes among the R. equi-isolates belonged to serotypes 1 and 2. Among the R. equi-isolates from horses haemagglutination-positive cultures were mainly found among isolates of serotype 1, those of serotype 2 were haemagglutination-negative. The R. equi-cultures isolated from humans showed no relation between serotype and haemagglutinating properties. Determination of antibiotic susceptibility revealed that all cultures were susceptible to erythromycin, gentamicin, imipenem, minocycline, neomycin, rifampicin, streptomycin and vancomycin, 71% and 75% were resistant or at least moderate susceptible to tetracycline and penicillin G, respectively. Almost all cultures were resistant to ceftazidime and most cultures were susceptible to cefotaxime. The cultures could be further characterized by restriction endonuclease digestion and pulsed field gel electrophoresis of their chromosomal DNA. After digestion with the restriction enzyme AsnI the resulting DNA-profile allowed a strain-specific characterization.

Actinomycetales Infections↗
PubMed1996

Amphotericin B intralipid formulation: stability and particle size.

Amphotericin B remains the drug of choice for treating systemic fungal infections, although toxicity limits its clinical use. Some studies reported the use of Intralipid deoxycholate amphotericin B as an alternative delivery system. An in-vitro study was performed to assess the compatibility of deoxycholate amphotericin B in Intralipid. With two types of dilution of deoxycholate amphotericin B (in 5% dextrose and Intralipid or in Intralipid alone) the solution stability was not constant with a clear yellow precipitate. We observed an increase in the size of the particles (1.5-4-fold). In light of these results Intralipid deoxycholate amphotericin B should not be routinely administered.

Amphotericin B↗
PubMed1995

Autosomal dominant exudative vitreoretinopathy: linkage analysis and its clinical application.

Close linkage without recombination (Zmax = 7.383 at Theta = 0.00) was found between the locus for autosomal dominant exudative vitreoretinopathy (Criswick-Schepens) and the locus D11S388 in 11q14.3-q21. We report on the application of data from linkage studies in the diagnostic management of this disease. To determine the disease risk for two newborn children of two affected mothers more precisely, indirect genotype analysis was performed by typing their DNA for three DNA polymorphisms, the loci of which have been shown to be closely linked to the locus of autosomal dominant exudative vitreoretinopathy.

Adult↗
PubMed1994

Mapping of the autosomal dominant exudative vitreoretinopathy locus (EVR1) by multipoint linkage analysis in four families.

Autosomal dominant exudative vitreoretinopathy is a disorder affecting primarily the development of the human retinal vascular system. The disease locus has recently been assigned to 11q13-q23 by linkage studies in two families. Two-point analysis on a total of four families has now revealed close linkage (Zmax = 8.34 at theta = 0.00) between the disease locus and D11S873. Multipoint linkage analysis mapped the disease locus between D11S527/D11S533 and D11S35 with a maximum lod score of over 11 directly at D11S873. No evidence appeared for genetic/linkage heterogeneity among the four families examined.

Chromosome Mapping↗
PubMed1994

Once daily antibiotic regimen in paediatric oncology.

The feasibility and efficacy of a once daily antibiotic regimen were assessed in children with malignant tumours. Over a 44 month period, 296 febrile episodes were treated with a regimen of once daily ceftriaxone-amikacin (and teicoplanin or vancomycin if the patient had a central line). The treatment was successful in 272 (92%) episodes without modification of the antibiotic regimen, and only one patient died of uncontrolled sepsis. A once daily antibiotic regimen is therefore feasible and worthwhile in the treatment of febrile episodes in children with cancer.

Adolescent↗
PubMed1992

The autosomal dominant familial exudative vitreoretinopathy locus maps on 11q and is closely linked to D11S533.

Autosomal dominant familial exudative vitreoretinopathy (adFEVR) is a hereditary disorder characterized by the incomplete vascularization of the peripheral retina. The primary biochemical defect in adFEVR is unknown. The adFEVR locus has tentatively been assigned to 11q by linkage studies. We report the results of an extended multipoint linkage analysis of two families with adFEVR by using five markers (INT2, D11S533, D11S527, D11S35, and CD3D) from 11q13-q23. Pairwise linkage data obtained in the two families were rather similar and hence have not provided evidence for genetic heterogeneity. The highest complied two-point lod score (3.67, at a recombination fraction of .07) was obtained for the disease locus versus D11S533. Multipoint analyses showed that the adFEVR locus maps most likely, with a maximum location score of over 20, between D11S533/D11S527 and D11S35, at recombination rates of .147 and .104, respectively. Close linkage without recombination (maximum lod score 11.26) has been found between D11S533 and D11S527.

Chromosome Mapping↗
PubMed1992

Micronucleus assay prediction and application optimized by cytochalasin B-induced binucleated tumor cells.

Improvement in the predictive assertion of the micronucleus assay was achieved by treating human malignant melanoma cells (Mewo) with cytochalasin B (CB), generating binucleated cells (BNC) representing cells after a single karyokinesis. Optimal cell binucleation was determined by testing several cytochalasin B concentrations and different incubation times. On average, 56% binucleated cells were found after incubation with 2 to 3 micrograms/ml cytochalasin B for 48 h. Cells with at least one micronucleus (Mn) were defined as fraction of cells with micronuclei and describes the degree of damaged cells. We found in binucleated cells 2.2 fold the fraction of cells with micronuclei than in mononucleated cells (MNC), as expected assuming that an induced micronucleus is associated with only one single daughter cell after mitosis. The mean of micronuclei per binucleated cells, however, was enhanced about 2.9 fold in relation to that of micronuclei per mononucleated cells and is related to the nuclear damage per cell. The application of cytochalasin B did not enhance the fraction of damaged cells although the degree of the injury per cell is intensified. A micronuclei promoting or inhibiting effect of the experimental design due to changes in cell proliferation was excluded by cytofluorometric investigations of DNA content and synthesis after cytochalasin B application. A comparison of the modified with the conventional micronucleus assay shows the superiority of the former.

Cell Line↗
PubMed1992

Congenital grouped albinotic spots: a rare anomaly of the retinal pigment epithelium.

We describe the fundus findings of a 6-year-old girl with congenital grouped albinotic retinal pigment epithelial spots distributed over the fundus including the macular area. Apart from the fundus changes functional and electrophysiologic findings were normal, and the family history was uneventful. At follow-up 3 years later, no progression was noted.

Albinism, Ocular↗
PubMed1991

Tumor radiosensitivity prediction by the cytokinesis-block micronucleus assay.

An in vivo to in vitro cytokinesis-block micronucleus assay technique using cytochalasin B (Cyt-B) was established in xenografted human and murine tumors, and the correlation between radiosensitivity measured by this assay and that measured by a colony-forming assay was investigated. Tumors were irradiated in situ, excised immediately, and disaggregated to single cells that were plated for the micronucleus and colony-forming assays. Some of the tumor cells were irradiated in vitro rather than in vivo. For the micronucleus assay, Cyt-B (0.5-3 micrograms/ml) was added to dishes soon after plating or in vitro irradiation and the cells were subsequently fixed and stained at intervals (12-144 h). The micronucleus frequency in binucleate cells was evaluated under conditions of maximum yield of the binucleate cells. The micronucleus frequency after irradiation was quite variable depending on the tumor type and the average number of micronuclei per single binucleate cell after 4 Gy ranged from 0.2 to 1.4. The results of in vitro irradiation were not significantly different from those of in vivo irradiation for all tumors. A good correlation was found between the radiosensitivity determined by the micronucleus assay and that found with the colony-forming assay in six human tumors (r = 0.94 approximately 0.98) but not in four murine tumors because of one exceptional tumor. When this tumor was excluded, a correlation was also found for the remaining nine tumors (r = 0.62 approximately 0.96). These results indicated that the cytokinesis-block micronucleus assay has some promise as a rapid predictive assay of radiosensitivity.

Animals↗