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Biomedical subjects

A Schaaf

Publications and source records attributed to A Schaaf.

13 recordsLinked to original sources
PubMed2003

Gene delivery into prostate cancer cells by holmium laser application.

New approaches to treat prostate cancer (PCA) are utilizing gene therapy and aim to correct the disease at the genetic level. Getting a gene efficiently into the target cell is the subject of much interest. We used a holmium laser for transfecting rat PCA cells with the reporter gene pEGFP. By FACS analysis and fluorescence microscopy, we could demonstrate that cellular delivery of plasmid DNA was possible with high efficiencies up to 41.3%. Therefore, transfection of PCA cells by holmium laser might offer a promising new gene transfer strategy to PCA with minimal invasiveness.

Adenocarcinoma↗
PubMed2003

[A New Ex-Vivo 3D Bladder Matrix Model for Standardised Evaluation of Urothelial Transfection Methods].

PURPOSE: Gene therapy strategies are a promising new alternative option in the treatment of cancer diseases and great effort is dedicated to the development of new gene transfer methods. At present, in vitro cell culture experiments or in vivo animal trials are the only available alternatives in the search for new gene transfer methods. We attempted to develop and evaluate a new 3D matrix model as a step between in vitro experiments and animal trials. MATERIALS AND METHODS: We generated a convenient model with an agarose gel as a basis for small intestinal submucosa or a polyethylene membrane. The produced model consisting of human smooth muscle cells and human bladder carcinoma cells was transfected with a modified standard Lipofectamine trade mark 2000 transfection procedure and visualised by fluorescence microscopy after cryo-sectioning. RESULTS: With the help of this new technique it is possible to generate three dimensional tissues consisting of different types of cells in which the cells are adherent on the polyethylene and the SIS-membrane during the entire treatment. The resulting model was successfully transfected with the pEGFP-N1 plasmid. CONCLUSIONS: This new three dimensional model allows the standardised evaluation of new transfection methods on multilayered ex-vivo generated tissues consisting of different cells.

Cell Line, Tumor↗
PubMed2001

Association of chronic lymphocytic leukemia with specific alleles of the HLA-DR4:DR53:DQ8 haplotype in German patients.

The etiology of chronic lymphocytic leukemia (CLL) remains unknown, though a genetic susceptibility has been suggested. Results of complete DNA typing of HLA alleles in CLL patients are lacking. We compared HLA class I and class II frequencies in 101 German CLL patients and 157 healthy German controls as determined by PCR-SSP/SSO DNA analysis and serologic typing. The most striking difference was the increased frequency of HLA-DRB4*0103 [relative risk (RR) = 2.74, p < 0.0025] among patients. The presence of alleles HLA-DRB1*0401, HLA-DQB1*0302 and HLA-DPB1*0301 as well as of homozygosity for HLA-DQB1 was also associated with a higher risk for CLL, though none of these differences remained significant after correction for multiple comparisons. No association was found for any HLA class I allele. Haplotype analysis revealed a CLL-specific linkage disequilibrium for HLA-DRB1*0401:DRB4*0103 and HLA-DRB4*0103:DQB1*0302. Our results suggest that CLL could be associated with distinct class II alleles of the Caucasian haplotype HLA-DR4:DR53:DQ8, which has also been related to a susceptibility for several auto-immune diseases. The positive, though weak, association of CLL with HLA-DPB1*0301 might represent an independent susceptibility factor since no linkage disequilibrium existed with any of the other CLL-associated alleles. None of the previously reported associations with HLA class I antigens was confirmed. Our results suggest that factors within or close to the human MHC class II region confer susceptibility to CLL.

Alleles↗
PubMed2001

Brain glioma and human leukocyte antigens (HLA)--is there an association.

Expression of human leukocyte antigens (HLA) is important for the immune response against infectious agents and malignant cells. Association of single HLA antigens or HLA haplotypes with disease has been investigated previously, and positive correlations between HLA and some cancers, such as cervical or nasopharyngeal carcinomas have been reported. In the present study, HLA antigen frequencies of 65 adult Caucasian patients with low-grade, anaplastic, or malignant astrocytic glioma (WHO grades II-IV) were compared with 157 racially similar, asymptomatic control individuals. Both standard serologic and PCR techniques for HLA typing were employed for all patients and controls. Our results suggest a positive association between single HLA antigens and presence of symptomatic cerebral glioma. Compared with the control population, patients positive for HLA-A*25 had a 3.0-fold increased risk of glioma (p = 0.04), patients positive for HLA-B*27, a 2.7-fold risk (p = 0.03), and patients positive for HLA-DRB1*15, a 2.2-fold risk (p = 0.03), whereas HLA-DRB1*07 was associated with a 0.4-fold decreased risk of glioma (p = 0.02). Occurrence rate of some HLA antigen combinations and estimated haplotypes was also different in glioma patients. Thus, HLA-DRB1*15:DRB5*(51) occurrence in combination with HLA-DRB1*11 was associated with a 13.4-fold increased risk of glioma (p = 0.001), and the incidence of HLA-Cw*6:DRB1*07 with a 0.2-fold decreased risk of glioma (p = 0.03). In conclusion, single HLA antigens and their combinations and estimated haplotypes are possibly significantly more or less frequent in persons developing symptomatic cerebral glioma during their adult life, compared with asymptomatic individuals.

Adult↗
PubMed2000

HLA-A, B, Cw and DRB1, DRB3/4/5, DQB1, DPB1 frequencies in German immunoglobulin A-deficient individuals.

HLA class I and II frequencies and haplotype frequencies were determined in 80 German immunoglobulin (Ig)A-deficient individuals and 157 healthy controls with normal IgA levels using serological and DNA typing methods. For several alleles, significant associations were found, which could be explained mainly in the context of a positive association with three different extended haplotypes (HLA-B*08:DRB1*0301: DQB1*0201, HLA-B*14:DRB1*0102:DQB1*0501 and HLA-B*44:DRB1*0701:DQB1*0202) and a negative association with a fourth haplotype (HLA-B*07:DRB1*1501:DQB1*0602). Furthermore, for the first time this study reports a positive association of IgA deficiency with DPB1 alleles. Homozygosity rate for the gene loci DRB1 and DQB1 was increased in IgA deficiency. Further analysis suggested a different pattern of HLA associations depending on the degree of IgA deficiency and the gender of the IgA-deficient individuals.

Alleles↗
PubMed1999

Shape of the orbital opening: individual characterization and analysis of variability in modern humans, Gorilla gorilla, and Pan troglodytes.

The description of the human orbital shape is principally qualitative in the classical literature, and characterised by adjectives such as circular, rectangular or quadrangular. In order to provide a precise quantification and interpretation of this shape, a study based on automatic image analysis and Fourier analysis was carried out on 45 human skulls (30 males, 15 females), and for comparison on 61 skulls of Gorilla gorilla (40 males, 21 females), and 34 skulls of Pan troglodytes (20 males, 14 females). Sexual dimorphism in the shape of the orbital opening was not demonstrated. Its dominant morphological features could be characterized by Fourier analysis; elliptical elongation and quadrangularity were dominant morphological features of the shape of the orbital opening in the three species. Elliptical elongation was more marked in humans and Pan, whereas quadrangularity was particularly emphasized in Gorilla. An intraspecific variability of the shape of the orbital opening existed in humans, Gorilla and Pan, and seemed close in the three species. Interspecific partition between humans, Gorilla and Pan was demonstrated despite the variability observed in the three species studied. Interspecific differences between Gorilla and the Pan-humans group were principally explained by the differences in quadrangularity, and by differences in orientation of triangularity and pentagonality. Differences in the shape of the orbital opening between humans and Pan were principally explained by differences in hexagonality, and by differences in orientation of quadrangularity. A closeness of shape between some humans and some individuals in Pan and, to a lesser degree, with some individuals in Gorilla was observed, demonstrating the existence of a morphological continuum of the shape of the orbital opening in hominoids.

Animals↗
PubMed1998

Shape of the piriform aperture in Gorilla gorilla, Pan troglodytes, and modern Homo sapiens: characterization and polymorphism analysis.

By using new methodologies based on automatic image analysis, the shape of the piriform aperture was analyzed in Gorilla gorilla (33 males, 13 females), Pan troglodytes (35 males, 22 females), and modern Homo sapiens (30 males, 12 females). The determination of the piriform aperture index (breadth/height) allowed the authors to demonstrate a marked elongation of the aperture in Homo compared with Gorilla and Pan. Individual characterization of the shape was possible with great precision and without ambiguity by using Fourier analysis. An absolute, interspecific partition between Gorilla, Pan, and Homo resulted from the canonical discriminant analysis of the Fourier descriptors. However, a closeness of shape between some individuals in Pan and some in Gorilla and Homo was observed, demonstrating a morphological continuum of the shape of the piriform aperture in hominoids: Pan was in intermediate position between Gorilla and Homo. Interspecific differences between Homo and the group Pan-Gorilla were explained principally by the differences in elongation (amplitude of the second harmonic) and pentagonality (amplitude of the fifth harmonic) and by differences in orientation of quadrangularity (phase of the fourth harmonic). Differences in the shape of the piriform aperture between Pan and Gorilla were explained by differences in orientation of elongation (phase of the second harmonic) and by differences in the component of triangularity (amplitude of the third harmonic). In Gorilla and Pan, the little, elongated, and relatively trapezoidal piriform aperture seems to be a shared primitive feature (plesiomorphic), whereas an elongated piriform aperture seems to be a characteristic and derived feature (apomorphic) of modern Homo sapiens.

Animals↗
PubMed1996

Relative position and extent of the nasal and orbital openings in Gorilla, Pan and the human species from the study of their areas and centres of area.

In order to quantify the relative position and extent of the nasal and orbital openings in hominoid primates, a new methodology based on image analysis was developed and applied to a series of 134 hominoid skulls (52 Gorilla gorilla; 30 Pan troglodytes; 44 Homo sapiens, and, as comparison material, 8 Pongo pygmaeus). The areas and the centres of area of the orbital and nasal openings were determined automatically. The orbitonasal triangle connecting these three centres of area was then constructed. This triangle was used to quantify the elongation of the face. It was most elongated in gorilla, shortest in the human species and intermediate in Pan; the elongation in Pongo was close to that in Gorilla. The proportions of the areas of the orbital and nasal openings in the face were related to the extent of the bony structures of the midface and were thus used to quantify the facial robustness. A robust face was demonstrated in Gorilla, but a gracile face in the human species. Robusticity in Pan was intermediate.

Anatomy, Comparative↗
PubMed1996

Indocyanine-green angiography in patients with occult choroidal neovascularization.

Several studies have stressed the role of indocyanine-green (ICG) angiography in patients with occult choroidal neovascularization (O-CNV) secondary to age-related maculopathy (ARM). The present study was undertaken to evaluate the percentage of eyes that could be converted from O-CNV without suffering pigment epithelial detachment (PED) in well-defined CNV using ICG angiography with a scanning laser system. A total of 112 patients with ARM and O-CNV without PED were included in this prospective study. All patients underwent ICG angiography with a scanning laser system. The early phase (first 3 min) of the ICG angiogram was analyzed for the presence of a neovascular network, whereas focal or irregular hyperfluorescence was noted in the late phase. The early phase of the ICG angiograms revealed in 62 (55%) eyes a well-defined CNV. In 55 of these eyes, late irregular hyperfluorescent and hypofluorescent zones were observed. Another 27 eyes presented with focal hyperfluorescent areas in the latephase studies without having shown a well-demarcated area of neovascularization in the early phase of the ICG angiogram. This study confirms that ICG angiography is an important adjunctive method to fluorescein angiography. In more than 50% of eyes with O-CNV the ICG angiograms obtained with a scanning laser ophthalmoscope enable the visualization of a neovascular network in the early phase.

Aged↗
PubMed1994

[HLA and selective IgA deficiency].

A selective deficiency of IgA is developed significantly (p < 0.05) more frequently by HLA-A2-negative than by HLA-A2-positive healthy persons. The frequent combination of A1/A3 is absent. The incidence of HLA-B8-positive persons is increased (p < 0.01). A selective disadvantage is discussed.

Gene Frequency↗
PubMedDate not supplied

In vitro transfection of human bladder cancer cells by acoustic energy.

BACKGROUND: The objective of this study was to examine and quantify the shock-wave-induced transfection of human bladder carcinoma cells. MATERIALS AND METHODS: Cell suspensions were transfected with different concentrations of the pEGFP-N1 plasmid. Shock-waves were applied in a degassed water bath with different numbers of impulses at different energy levels. Additionally, the effects of different DNA concentrations, frequencies and the absence/presence of a liquid air border were examined. RESULTS: After shock-wave application, the transfection rate increased up to a maximum of 27.10% after 1000 impulses at an energy level of 0.5 mJ/mm2. In comparison negative control groups were transfected significantly below 1%. An increase in acoustic power and frequency and of DNA concentration and the presence of a liquid-air border resulted in an increasing transfection rate. CONCLUSION: The results demonstrate that naked plasmid DNA can easily and effectively be delivered to malignant urothelial cells in vitro upon exposure to lithotripter-generated shock-waves.

Acoustic Stimulation↗