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Biomedical subjects

A Berndt

Publications and source records attributed to A Berndt.

At least 37 records · Page 2Linked to original sources
PubMed2001

Fibrillary co-deposition of laminin-5 and large unspliced tenascin-C in the invasive front of oral squamous cell carcinoma in vivo and in vitro.

PURPOSE: Invasion of oral squamous cell carcinoma (OSCC) is associated with laminin-5 (Ln-5) synthesis, focal Ln-5 loss from the basement membrane (BM), and Ln-5 depositions in the stroma beneath invading carcinoma cell complexes. METHODS: The study is focused on the laminin-5 matrix reorganisation within the stroma of the OSCC invasive front outside the basement membrane region as well as in OSCC-fibroblast co-culture in relation to unspliced tenascin-C (Tn-CL) and ED-B+ fibronectin (ED-B+ fn) using confocal laser scanning microscopy. RESULTS: In vivo, Ln-5 was demonstrated as fibrillary deposition in the invasive front. It was co-localised to Tn-CL. In pure OSCC cultures, Ln-5 was synthesised and deposited as a spot-like matrix. Fibrillary structures were not found. In contrast, in the OSCC-fibroblast co-culture, a fibrillary Ln-5 matrix organisation was revealed within the interface of OSCC cell-fibroblast complexes exclusively in co-distribution with Tn-CL and ED-B+ fn. CONCLUSION: At least in vitro, a carcinoma cell-stroma fibroblast interaction is indispensable for fibrillary Ln-5/Tn-CL matrix organisation. Behind the parallels to the initial basement membrane formation in organotypic cultures, the fibrillary multiprotein complexes at the OSCC cell-fibroblast interface are suggested as provisional basement membrane fragments with a possible supportive role for invasive tumour behaviour.

Carcinoma, Squamous Cell↗
PubMed2001

[Experimental 5-aminolevulinic acid-induced photodynamic therapy (ALA-PDT) of oral carcinomas. Procedures in treatment of solid tumors and elucidation of cell death].

AIMS: Of our own patients suffering from oral squamous cell carcinoma (OSCC), 96% possessed a 5-aminolevulinic acid (ALA)-induced tumor fluorescence. Consequently, the ALA-induced fluorescence of OSCC is suggested as an ideal tool for selective photodynamic therapy (PDT). The aim of the study was to demonstrate selective tumor damage and to analyze the cell death mode (apoptosis vs. necrosis) of OSCC cells in cell culture and in solid, deeply invasive xenotransplants in immunodeficient nude mice using intratumoral laser illumination. MATERIAL AND METHODS: For ALA-PDT, laser light (635 nm, 0.75 W, 10 min, cooled application system) was used intratumorally as well as in cell culture. The therapeutic response was controlled by histology and immunohistochemistry (Ki-67 index). The apoptosis was evaluated by the TUNEL method and in vitro by flow cytometry. Mutations in the apoptosis-controlling p53 gene were investigated by direct genomic sequencing. RESULTS AND CONCLUSIONS: 1. Although all OSCC exhibited an ALA-induced fluorescence in vivo, the evaluation of the cell lines showed differences in intensity of the ALA-induced fluorescence. This points to a different sensitivity of OSCC for ALA-PDT. 2. The use of a cooled laser light application system allowed intratumoral radiation and treatment of deeply invasive OSCC regions. 3. The cytotoxic effect of ALA-PDT in OSCC is evidenced by a diminution of proliferative activity and necrosis but not by apoptosis. 4. Functional mutations within the p53 gene were considered a possible reason for the absence of apoptosis induction by ALA-PDT.

Aminolevulinic Acid↗
PubMed2001

Influence of surface-modifying surfactants on the pharmacokinetic behavior of 14C-poly (methylmethacrylate) nanoparticles in experimental tumor models.

PURPOSE: The aim of this study was to investigate the different pharmacokinetic behavior of surface-modified poly(methylmethacrylate) (PMMA) nanoparticles. METHODS: The particles were 14C-labeled and coated with polysorbate 80, poloxamer 407, and poloxamine 908. Plain particles served as control particles. In vivo studies were performed in three tumor models differing in growth, localization, and origin. Particle suspensions were administered via the tail vein, and at given time animals were killed and organs were dissected for determination of PMMA concentration. RESULTS: For the PMMA nanoparticles coated with poloxamer 407 or poloxamine 908, high and long-lasting concentrations were observed in the melanoma and at a lower level in the breast cancer model. In an intracerebrally growing glioma xenograft, the lowest concentrations that did not differ between the tumor-loaded and tumor-free hemispheres were measured. Organ distribution of the four investigated batches differed significantly. For instance, poloxamer 407- and poloxamine 908-coated particles circulated over a longer period of time in the blood, leading additionally to a higher tumor accumulation. In contrast, plain and polysorbate 80-coated particles accumulated mainly in the liver. The strong expression of vascular endothelial growth factor and Flk-1 in the melanoma correlated with high concentrations of PMMA in this tumor. CONCLUSION: The degree of accumulation of PMMA nanoparticles in tumors depended on the particle surface properties and the specific growth differences of tumors.

Animals↗
PubMed2001

Spleen enlargement in healthy donors during G-CSF mobilization of PBPCs.

BACKGROUND: Recombinant human G-CSF is widely used to mobilize PBPCs in healthy donors for allogeneic transplantation. There have been concerns about donor safety because of splenic ruptures during G-CSF application. To address this problem, changes in splenic size in 91 healthy donors during G-CSF mobilization of allogeneic PBPCs were investigated. STUDY DESIGN AND METHODS: For mobilization, G-CSF in a dosage of 7.5 microg per kg per day was administered for 5 days and PBPC collection started Day 5. Splenic size was determined by ultrasound before G-CSF application was started and on the day of the first apheresis. RESULTS: The mean increase in splenic length was 11 mm (range, 0-28 mm; p<0.0001), whereas a mean increase of 5 mm in width (range, 0-14 mm; p<0.0001) was measured. No major side effects could be observed. There was no significant correlation between the increase in splenic size and the hematologic values, or the age and body-mass index. In a multivariant analysis, no independent risk factor for the development of a spleen enlargement over 19 mm in length and 9 mm in thickness was found in 20 percent of investigated donors. CONCLUSION: In this prospective trial, a significant spleen enlargement was observed in healthy donors during G-CSF mobilization of allogeneic PBPCs. Further investigations are needed to define the degree of spleen enlargement with higher G-CSF dosages to improve donor safety.

Blood Donors↗
PubMed2001

A comparative quantitative analysis of laminin-5 in the basement membrane of normal, hyperplastic, and malignant oral mucosa by confocal immunofluorescence imaging.

Laminin-5 (Ln-5) is a heterotrimeric basement membrane (BM) molecule (alpha3beta3gamma2). It is a principal protein constituent of the anchoring filaments, which connect the BM with the hemidesmosomes of the basal keratinocytes and possess a crucial function in keratinocyte adhesion. Confocal immunofluorescence imaging is introduced for a quantitative evaluation of the Ln-5 content in the BM of oral squamous epithelium. The BM of normal oral mucosa was used as a reference (100%) for comparative analysis and showed a nearly uniform Ln-5 immunofluorescence intensity (99-100%). In all hyperplastic lesions of oral mucosa, the Ln-5 immunofluorescence intensity was increased (107-141%). The increased Ln-5 content in the BM of hyperplastic lesions suggests an increased keratinocyte-BM adhesion, possibly resulting in a higher stability of the oral mucosa. In contrast, in the oral squamous cell carcinoma (OSCC) invasive front, the remaining BM segments were characterized by a decrease in Ln-5 immunofluorescence intensity (35-74%). A stronger decrease of Ln-5-linked kerationocyte-BM adhesion correlates with a higher tumor grade. Because in central areas of carcinoma BM segments with a normal Ln-5 content could be demonstrated, the fundamental Ln-5 diminution in BM segments of the invasive front should be considered as an invasion-associated phenomenon.

Basement Membrane↗
PubMed2001

An empirical analysis of stressors for gay men and lesbians.

This research describes the empirical classification of stressors for gay men and lesbians. Volunteer respondents were recruited through a free local gay and lesbian newspaper, through gay and lesbian student organizations nationwide, through gay and lesbian bookstores nationwide, and at a gay festival in St. Louis. Nine hundred seventy-nine (979) participants completed a 70-item measure with stressors that had been identified in previous qualitative research. Participants were asked to indicate the degree to which they had experienced stress associated with a variety of experiences. Participants also completed a measure of dysphoria (CES-D), responded about their degree of openness regarding sexual orientation, and provided information about their relationship status and involvement with gay groups and activities. Using confirmatory factor analysis, a six-factor model was predicted to account for the data. One-factor, six-factor, and ten-factor models were tested. The ten-factor model yielded the best fit with the data and accounted for 63.5% of the variance. The factor structure remained stable when gay men were compared to lesbians, when those endorsing a predominantly gay versus exclusively gay orientation were compared, and when those in a relationship were compared to those who were not in a relationship. Increased gay stress was associated with more dysphoria. Implications of these findings are discussed and directions for future research are considered.

Adult↗
PubMed2000

Monoclonal antibodies against porcine macrophages.

Two mouse monoclonal antibodies (MAB) (clones 2G6 and 2B10) directed against porcine macrophages are described that are suitable for use in immunohistochemistry, FACS analysis and western blot. As immunogen, porcine cells from bronchoalveolar lavage (BAL) were used. The MABs obtained belonged to the mouse IgG1 subclass. The molecular weights of the corresponding antigens were detected by western blot under non-reducing conditions (2G6: 140-150kDa; 2B10: 140-145kDa). For specificity screening, porcine snap-frozen tissues of lung, lung lymph node, tonsil, spleen, thymus, brain, liver, gut and kidney were used. The MABs were able to identify cell populations of the mononuclear phagocytic system in these organs. While MAB 2G6 detected tissue macrophages (sinusoidal lymph node macrophages, red pulp spleen macrophages, Kupffer cells, Langerhans cells, thymus macrophages, macrophages of lung and macrophages of kidney), MAB 2B10 stained cells scattered in the lymph node (subsinusoidal, interfollicular and follicular macrophages) and in the lung interstitium. Additionally, it showed reactivity with Kupffer cells, spleen and kidney macrophages. An immunoreactivity of the MABs could be established also for human but not for bovine and avian macrophages. By flow cytometric analysis, MAB 2B10 reacted with a subpopulation of BAL and peritoneal cells. Antibody 2G6 detected macrophages of the BAL and the peritoneal fluid as well as peripheral blood monocytes.

Animals↗
PubMed2000

[POEMS syndrome--a case report].

One rare case of POEMS syndrome is presented. In a 39-year-old male patient a progressive numbness in hands and feet developed within 5 years. Admission with increasing dyspnoea and lower leg edema. In swollen inguinal lymph nodes a lymphadenopathy with angiofollicular hyperplasia and vascular-plasmacellular proliferation was diagnosed and classified as Castleman-like histologic features. In os ilium an osteosclerotic plasmocytoma with restriction of kappa light chains was found. Potential pathomechanism of POEMS syndrome are discussed.

Adult↗
PubMed2000

Simultaneous enzyme overlay membrane (EOM)-based in situ zymography and immunofluorescence technique reveals cathepsin B-like activity in a subset of tumour vessels.

The analysis of the invasion front of oral squamous cell carcinoma (OSCC) has revealed a fundamental invasion-associated remodelling of the extracellular matrix as the result of a complex regulated interplay of matrix synthesis and matrix degradation. Cysteine proteinases, in particular cathepsin B, are implicated in tumour invasion in vivo and in vitro and are thought to be important mediators of metastasis. An in situ zymographic assay based on enzyme overlay membranes (EOMs) was established to define the tissue localisation of cathepsin B activity in OSCC. Using confocal laser scanning microscopy we present a double-labelling method for the rapid and reproducible simultaneous detection of cathepsin B-like activity and cellular or extracellular antigens based on an EOM and immunofluorescence technique on frozen sections. Applying this method, cathepsin B-like activity was mainly found in vascular structures within the invasive front of OSCC. Therefore, the results suggest a particular pathogenic role of cathepsin B in tumour angioneogenesis. The method can simply be transferred to other enzymes and can be recommended for more extensive studies of proteolytic activity in human malignancies.

Carcinoma, Squamous Cell↗
PubMed2000

[Laminin-5 in diseases of the oral cavity].

The basement membrane molecule laminin forms a family of proteins. Laminin-5 was identified as key protein in the anchoring filaments of the basement membrane. The anchoring filaments connect the basement membrane to the epithelial cells and together form the epithelial adhesion complex. Disturbances in the epithelial adhesion complex result in subepithelial blistering dermatosis. Autoantibodies against laminin-5 are found in cicatricial pemphigoid. Mutations in genes of laminin-5 with loss of the protein cause epidermolysis bullosa Herlitz. It can be determined during prenatal genetic diagnostic testing. Laminin-5 supports migration of keratinocytes and forms the basis for migrating keratinocytes in oral wound healing. Positive re-epithelialization via laminin-5 has been the subject of experimental studies. Oral squamous cell carcinomas are found to have a focal loss of laminin-5 in conjunction with a loss of the cellular receptor, and increased synthesis of laminin-5 by budding tumor cells has been observed along with deposition of the protein in the stroma. As a result of these observations laminin-5 has been suggested as a route of invasion. Quantitative assessment of this phenomenon and the modulation of laminin-5-tumor cell interaction offer new and hopeful means of describing and affecting the invasive behaviour of oral squamous carcinoma.

Adult↗
PubMed2000

Size and positioning reproducibility of an 192Ir brachytherapy stepping source.

In this paper we describe techniques for measuring the dimensions and position reproducibility of an 192Ir brachytherapy stepping source. Measurements were carried out using a 0.25x10x152 mm3 collimator placed in front of a detector of our own design. The brachytherapy source was translated past the collimator in 0.025 mm increments using a stepper motor. The source was found to be 3.58 mm long and 0.69 mm wide, which is in good agreement with the manufacturer's values of 3.5x0.6 mm2. The source position was reproducible to within 0.12 mm.

Biophysical Phenomena↗
PubMed2000

Immunolocalization of tenascin-C, alpha9 integrin subunit, and alphavbeta6 integrin during wound healing in human oral mucosa.

Tenascin-C (TN-C) and its isoforms are multidomain extracellular matrix (ECM) proteins that are believed to be involved in the regulation of stromal-epithelial interactions. Some of the interactions between TN-C and cells are mediated by integrins. In this study we analyzed the expression of TN-C and its large molecular weight splice isoform (TN-C(L)) and the putative TN-C-binding alpha9 and alphavbeta6 integrins during human wound repair. In 3-day-old oral mucosal wounds, immunoreactivity for alpha9 integrin localized abundantly at the migrating basal wound epithelial cells. TN-C and TN-C(L) were localized in the matrix between and underneath alpha9-expressing epithelial cells. In parallel with gradual downregulation of alpha9 integrin immunoreactivity in 7-day and older wounds, the expression of alphavbeta6 integrin was temporarily induced. Integrin alphavbeta6 co-localized in the same area as TN-C and TN-C(L) immunoreactivity at the cell-cell contacts of the basal and suprabasal cell layers of the wound epithelium. During granulation tissue formation and reorganization from 7 to 28 days after wounding, TN-C and TN-C(L) were abundantly localized in the granulation tissue. The findings show that TN-C(L) is expressed under the migrating epithelial front and in the granulation tissue during matrix deposition in wound repair. Preferential localization of alpha9 integrin in migrating epithelial cells and of alphavbeta6 integrin in epithelium after wound closure suggests different functions for these integrins in wound repair.

Alternative Splicing↗
PubMed1999

Combination of vaccination and competitive exclusion to prevent Salmonella colonization in chickens: experimental studies.

Vaccination and competitive exclusion (CE) represent accepted prophylactic measures to control Salmonella infections in chickens. To use the advantages of both the CE technique and vaccination with live Salmonella vaccines the combination of these methods was studied. In three experiments, SPF chickens were pre-treated using combined or unique administration of CE and vaccination with a live Salmonella typhimurium strain on days 1 and 2 of life and challenged with the antibiotic resistant, but otherwise isogenic mutant of this Salmonella typhimurium strain on days 3, 15 or 40 of life. The caecal colonization of both the vaccine and the challenge strain and the antibody response after infection were examined to evaluate the protective effects of the different combinations. The exclusion effect of CE cultures against Salmonella infection could be seen in very young chicks and was still considerable on day 40 of life of the birds. The Salmonella wild-type strain used as vaccine alone also resulted in a substantial protective effect against homologous challenge. The combined administration of competitive exclusion and immunization using the Salmonella wild-type strain as vaccine resulted in a considerable additional protective effect above the level of the respective exclusive application of these prophylactic measures. Administration of the Salmonella vaccine strain prior to or simultaneously with the CE culture produced the best protective effect, because such combinations ensure an adequate persistence of the vaccine strain as prerequisite for the expression of colonization inhibition effects and a strong immune response. The full exploitation of this potential using attenuated live Salmonella vaccines will require the presence of high inhibitory and immunogenic properties in the vaccine strain after attenuation of a selected parent strain. The combination of competitive exclusion and vaccination as a new measure in integrated control programmes against Salmonella infection in poultry could result in a considerable increase of protection in both very young and older chickens.

Animals↗
PubMed1999

Synthesis and protein distribution of the unspliced large tenascin-C isoform in oral squamous cell carcinoma.

The inclusion or omission of the alternatively spliced region in the tenascin-C (Tn-C) mRNA gives rise to the large (Tn-C(L)) or small (Tn-C(S)) variant, respectively. Tn-C(L) is thought to be a typical component of provisional extracellular matrices (ECMs) and is expressed during tumour stroma remodelling. Tn-C(L) synthesis has been studied using RNA/RNA in situ hybridization, and Tn-C(L) protein distribution, using immunohistochemistry (clone BC-2), in 18 oral squamous cell carcinomas (OSCCs) of different grades of malignancy. While the Tn-C(L) protein was demonstrated within the whole stromal compartment regardless of grade of malignancy, the majority of the Tn-C(L) mRNA signal-bearing cells were carcinoma cells. Only a few stromal myofibroblasts were able to synthesize Tn-C(L), as revealed by alpha-smooth muscle actin double staining. In well-differentiated carcinomas (G1), the Tn-C(L) synthesizing carcinoma cells were localized as a single positive cell layer in the tumour stroma interface, particularly in invasive areas. A higher grade of malignancy (G2/G3) is associated with a significantly increased number of Tn-C(L) synthesizing carcinoma cells randomly distributed within the invading tumour areas. Double-staining experiments (Tn-C(L) mRNA ISH/BC-2 immunohistochemistry) indicate that these cells are capable of organizing and depositing a three-dimensional Tn-C(L) matrix. Even though an instructive and/or inductive role of the carcinoma cells in tumour stroma formation cannot be excluded, these results demonstrate that carcinoma cells can directly produce the ECM components of tumour stroma.

Basement Membrane↗
PubMed1999

[An unusual case of genital tuberculosis. A case report].

We represent and discuss etiology, diagnosis as well as differential diagnoses of tuberculous orchtitis referring to an actual case of this rare disease. In the least of all cases one can conclude from the clinical symptoms on the tuberculous origin of the disease. Other differential diagnoses will set more frequently due to rarity of this disease. Quite a lot of cases a bacterial superinfection veils the sterile leucocyturia as main characteristic of genitourinary tuberculosis. Imaging diagnostics frequently fails to give indications of tuberculous origin of the lesion. As before the evidence of Mycobacteria tuberculosis is the most important parameter to proof a tuberculosis. Despite required microbiological cultivation to make a resistogram the polymerase chain reaction is a high sensitive and comparable fast method for detection of Mycobacteria even from tissue. In such dubious cases we recommend to perform an operative denudation due to frequently difficult delimitation from malignant testicular tumours.

Antitubercular Agents↗