Biomedical subjects

A Berndt

Publications and source records attributed to A Berndt.

At least 55 records · Page 3Linked to original sources

PubMed1999

Expression of the transmembrane protein tyrosine phosphatase RPTPalpha in human oral squamous cell carcinoma.

Little is known about the role of protein-tyrosine phosphatases (PTPs), the cellular counterparts of protein-tyrosine kinases, both for normal growth regulation and for its dysregulation in cancer. The receptor-like PTPalpha (RPTPalpha) may play a positive role in growth regulation and has been shown to be overexpressed in colon carcinoma. An RNA/RNA in situ hybridisation protocol for RPTPalpha as well as RPTPalpha immunohistochemistry was developed to evaluate RPTPalpha expression in oral squamous cell carcinomas (OSCCs) of different histological grade and to reveal the synthetically active cells and their tissue distribution. In well-differentiated OSCC (G1), RPTPalpha mRNA could be detected by in situ hybridisation exclusively in stroma cells (fibro/myofibroblasts and inflammatory cells). A higher histological grade (G2/G3) was associated with an increased number of RPTPalpha-synthesising carcinoma cells haphazardly distributed within invading tumour areas. Consistent results were obtained by immunocytochemistry. Thus, both carcinoma dedifferentiation and stroma recruitment and activation seem to be associated with an upregulation of RPTPalpha expression in OSCC. The results speak in favour of the important role of activation of stroma fibro/myofibroblasts influencing the biological behaviour of epithelial tumours and also suggest that elevated RPTPalpha expression may be a more general marker for proliferating or dedifferentiated cells.

Carcinoma, Squamous Cell↗

PubMed1999

Unexpected effect of verapamil on oral bioavailability of the beta-blocker talinolol in humans.

PURPOSE: To quantitate the effect of verapamil administered orally, a calcium channel blocker and potent inhibitor of P-glycoprotein on oral pharmacokinetics of the beta1-adrenergic receptor antagonist talinolol, a substrate of P-glycoprotein. SUBJECTS AND METHODS: In a randomized, crossover placebo-controlled study, oral pharmacokinetics of talinolol (50 mg) after concomitant administration of single doses of R-verapamil (120 mg) or placebo were investigated in 9 healthy volunteers. Concentrations of talinolol, verapamil, and its main metabolite norverapamil were measured in serum with HPLC. Concentrations of talinolol were also measured in urine by HPLC. Standard pharmacokinetic parameters were calculated with noncompartmental procedures. RESULTS: The area under the concentration-time curve for talinolol from 0 to 24 hours was significantly decreased after R-verapamil versus placebo (721+/-231 ng x h x mL(-1) versus 945+/-188 ng x h x mL(-1); P < .01). Maximum serum concentration of talinolol was reached significantly earlier after R-verapamil compared with placebo (P < .05). Coadministration of R-verapamil did not affect the renal clearance or half-life of talinolol. Serum pharmacokinetics are paralleled by the results derived from urine concentrations of talinolol. CONCLUSION: This is the first study to show a decreased oral bioavailability of a P-glycoprotein substrate (talinolol) in humans as a result of coadministration of verapamil. This effect is assumed to be caused by changes of the intestinal net absorption of talinolol because its renal clearance remains unaffected by administration of R-verapamil. This unexpected effect of R-verapamil is most likely dose dependent as a result of an interplay between intestinal P-glycoprotein and gut metabolism.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

LacSwitch inducible mammalian expression system in mouse Swiss 3T3 fibroblasts.

Swiss 3T3 fibroblasts were transfected with the provided plasmids of LacSwitch Inducible Mammalian Expression System (Stratagene). Stable transfectants were selected, expanded and characterised. At first, the production of CAT in these cell lines could be induced by IPTG treatment, but the inducibility was lost after a few months in culture in a reproducible manner. Further analysis revealed that the transfectants did not lose the cat gene nor the lac repressor protein. As a result, we conclude that LacSwitch Inducible Mammalian Expression System needs further modification for use in Swiss 3T3 fibroblasts.

3T3 Cells↗

PubMed1999

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma.

The expression of laminin and fibronectin isoforms varies with cellular maturation and differentiation and these differences may well influence cellular processes such as adhesion and motility. The basement membrane (BM) of fetal oral squamous epithelium contains the laminin chains, alpha2, alpha3, alpha5, beta1, beta2, beta3, gamma1 and gamma2. The BM of adult normal oral squamous epithelium comprises the laminin chains, alpha3, alpha5, beta1, beta3, gamma1 and gamma2. A re-expression of the laminin alpha2 and beta2 chains could be shown in adult hyperproliferative, dysplastic and carcinomatous lesions. In dysplasia and oral squamous cell carcinoma (OSCC), multifocal breaks of the BM are present as indicated by laminin chain antibodies. These breaks correlate to malignancy grade in their extent. Moreover, in the invasion front the alpha3 and gamma2 chain of laminin-5 can immunohistochemically be found outside the BM within the cytoplasm of budding carcinoma cells and in the adjacent stroma. The correlation between the morphological pattern of invasive tumour clusters and a laminin-5 immunostaining in the adjacent stroma may suggest, first, that a laminin-5 deposition outside the BM is an immunohistochemical marker for invasion and second, that OSCC invasion is guided by the laminin-5 matrix. Expression of oncofetal fibronectins (IIICS de novo glycosylated fibronectin and ED-B fibronectin) could be demonstrated throughout the stromal compartment. However, the ED-B fibronectin synthesizing cells (RNA/RNA in situ hybridization) are confined to small stroma areas and to single stroma and inflammatory cells in the invasion front. A correlation of the number of ED-B fibronectin synthesizing cells to malignancy grade could not be seen. ED-B fibronectin mRNA-positive cells seem to be concentrated in areas of fibrous stroma recruitment with a linear alignment of stromal fibro-/myofibroblasts (desmoplasia). Double staining experiments (ED-B fibronectin in situ hybridization and alpha-smooth muscle actin immunohistochemistry) indicated that the stroma myofibroblasts are a preferential source of ED-B fibronectin. In conclusion, in OSCC, a fetal extracellular matrix conversion is demonstrable. Tumour cells (laminin alpha2 and beta2 chain) and recruited stromal myofibroblasts (oncofetal ED-B fibronectin) contribute to the fetal extracellular matrix milieu.

Adult↗

PubMed1999

Loss of laminin-5 in the epithelium-stroma interface: an immunohistochemical marker of malignancy in epithelial lesions of the breast.

AIMS: To demonstrate immunohistochemically the alpha3 and gamma2 chain of laminin-5 in benign epithelial and malignant lesions of the human breast. METHODS AND RESULTS: The alpha3 chain was identified by the monoclonal antibody BM165 and the gamma2 chain by GB3 in shock frozen samples using APAAP (alkaline phosphatase monoclonal anti-alkaline phosphatase) technique. The pre-existing breast epithelium, the 12 benign ductal and lobular proliferations and the three fibroadenomas showed a continuous immunostaining in the basement membrane region. In contrast to benign epithelial lesions, the 44 cases of invasive breast carcinoma showed a loss of the laminin-5 chains in more than 50% of the carcinoma stroma interface. Twenty-four out of the 44 invasive carcinomas revealed a complete loss of laminin-5 immunostaining. Focal defects of the laminin-5 immunostaining were also found in ductal carcinoma in situ in its pure form. CONCLUSIONS: As recently described, the malignant transformation of breast epithelium with expression of an invasive phenotype is associated with a decrease of hemidesmosomes. The reduced immunostaining of laminin-5 is in line with this finding because laminin-5 represents the major component of the anchoring filaments attaching hemidesmosomes to the basement membrane. We feel that immunohistochemical demonstration of laminin-5 may serve as a marker of benignity in epithelial breast lesions. While other carcinoma types exhibit an increased laminin-5 deposition, which has been suggested as an invasion promoting factor, the loss of laminin-5 in breast cancer supports the view that breast carcinomas do not utilize laminin-5 for invasion.

Breast Neoplasms↗

PubMed1999

Studies on the influence of combined administration of ochratoxin A, fumonisin B1, deoxynivalenol and T2 toxin on immune and defence reactions in weaner pigs.

In weaners, combined administration of fumonisin, deoxynivalenol and T2 together with ochratoxin A in quantities expected to be present in feeds of central European origin resulted, as a rule, in changes identical to those observed after single administration of ochratoxin A. Such reactions were partly compensated. Synergistic amplification of immunosuppressive changes due to the simultaneous intake of these mycotoxins in low concentrations is not to be expected.

Animals↗

PubMed1999

Studies of the influence of ochratoxin A on immune and defence reactions in weaners.

Even in subtoxic amounts, the mycotoxin, ochratoxin A, produced immunomodulation in weaner pigs in a dose-dependent mode. In addition to increased counts of total leukocytes and neutrophils in the blood, reduced lymphocyte levels were observed. There was a striking increase in the counts of eosinophils and of apoptotic phagocytes. Functionally, there was a predominance of the production of reactive oxygen radicals in whole blood, reduced phagocytosis performance and reduced expression of a swine-specific surface marker (SWC1) on lymphocytes. In a few single experiments, clinical manifestations could be demonstrated. Lung clearance and the degree of severity of experimental pneumonia as well as cutaneous hypersensitization may be influenced by ochratoxin A.

Animals↗

PubMed1998

Evidence of ED-B+ fibronectin synthesis in human tissues by non-radioactive RNA in situ hybridization. Investigations on carcinoma (oral squamous cell and breast carcinoma), chronic inflammation (rheumatoid synovitis) and fibromatosis (Morbus Dupuytren).

The splicing variant of fibronectin containing the ED-B domain (oncofoetal fibronectin) occurs in foetal tissues, reparative processes, organ fibrosis and in tumour tissues. Consequently, a supportive effect of ED-B+ fibronectin for tissue remodelling and tumour progression is assumed. A non-radioactive RNA-RNA in situ hybridization protocol for the investigation of ED-B+ fibronectin synthesis applicable in human tissues is introduced. The ED-B+ fibronectin synthesis was investigated in human disease processes, for which the occurrence of ED-B+ fibronectin is well demonstrated by immunohistochemistry (rheumatoid arthritis, oral squamous cell carcinoma, invasive ductal carcinoma of the breast and nodular palmar fibromatosis). The ED-B+ fibronectin synthesis could be shown in lining cells and in endothelial cells of synovial villi in rheumatoid arthritis, in stromal cells of oral squamous cell carcinoma and invasive ductal carcinoma and in fibro-/myofibroblasts in the proliferative and early involutional phase of nodular palmar fibromatosis. By means of double labelling (alpha-smooth muscle actin immunostaining - ED-B+ fibronectin in situ hybridization), the ED-B+ fibronectin synthesis could be shown to be a typical feature of myofibroblasts. In contrast to the often diffuse ED-B+ fibronectin immunostaining, only a few synthetically active stromal cells were observed focally accentuated within the tumour, which were interpreted as hot spots of tumour-stroma interaction.

Arthritis, Rheumatoid↗

PubMed1998

Evaluation of microvessel density by computerised image analysis in human renal cell carcinoma. Correlation to pT category, nuclear grade, proliferative activity and occurrence of metastasis.

A high microvessel density is suspected to favour tumour progression and the occurrence of metastasis. To elucidate the significance of abundant vessels for the behaviour of human renal carcinomas, the microvessel density of 110 renal cell carcinomas was correlated to pT category, nuclear grade, proliferative activity, occurrence of metastasis and relapse-free survival interval. The microvessels were quantified using CD31 immunostaining of endothelial cells and computer-aided image analysis. The rules for reproducible microvessel counting, as defined by Weidner, were strictly observed. A statistically significant relationship between the microvessel density and nuclear grade, proliferative activity, occurrence of metastasis and relapse-free survival was found; only for tumour size could no such relation be seen. Perplexingly, there is a diminution of microvessel density in association with increasing nuclear grade, proliferative activity, relapse-free survival interval and frequency of metastasis. This finding is contradictory to the hypothesis that an increasing microvessel density indicates a worsening prognosis.

Antibodies↗

PubMed1998

[Cell kinetics of oral squamous epithelial carcinomas. Determination of the proliferation index and apoptosis rate with the TUNEL method].

Tumour growth is directly related to the multiplication of tumour cell numbers which can be caused, firstly, by increased proliferation and, secondly, by prolongation of the life span of tumour cells. The aim was the quantification of the increase and decrease (apoptosis) in cell numbers in relation to the cytological grading of oral squamous epithelial cell carcinoma. Proof of apoptosis-specific fragmentation of DNA (double-strand breaks) by the TUNEL method (TdT-mediated dUTP nick end labelling) and of proliferative activity by the monoclonal antibody MIB 1 was found in 41 oral squamous epithelial carcinomas of different grading. With progression of the cytological grading, an increase of proliferative activity and a decrease of apoptotic activity occurs. The apoptosis rates were 13.5% for G1 carcinomas, 8.5% for G2 carcinomas and 6.1% for G3 carcinomas. The results confirm that during progression to higher malignant cellular phenotypes of oral squamous carcinoma, increased proliferative activity as well as reduced apoptosis rates contribute substantially to the multiplication of tumour cell numbers and show that during progression a loss of control of programmed cell death (apoptosis) occurs. However, the high standard deviations of apoptosis rates within the different grades disprove an individual prognostic significance.

Apoptosis↗

PubMed1998

[3-dimensional in vitro invasion model for oral squamous epithelial carcinomas. Evaluation of tumor and stromal cell properties as well as extracellular matrix].

UNLABELLED: Because tumour cell invasion is a three-dimensional process involving tumour cells as well as stromal cells, tumour invasion models should include equivalents of both compartments in a spatially defined organisation. AIMS: Evaluation of differentiation and invasive potential in relation to basement membrane (BM) formation of new human oral squamous cell carcinoma (OSCC) cell lines under the influence of fibromatosis fibroblasts in a 3D co-culture system (collagen type I/fibroblast-containing matrix). MATERIAL AND METHODS: OSCC cell lines were established and cultured on collagen type I matrix with and without the inclusion of fibro-/myofibroblasts derived from nodular palmar fibromatosis). Evaluation of invasion was done by conventional H & E staining after paraffin embedding; immunohistochemistry was performed for cytokeratins (MNF 116), involucrin (Sy5), vimentin (V9), collagen type IV (CIV22), laminin (alpha 1-chain, 4C7), and Ki-67 (MIB1); and electron microscopy followed. RESULTS: The OSCC cell lines PE/CA-PJ15, PE/CA-PJ34, PE/CA-PJ41 were invasive exclusively on gels containing fibroblasts with stratification of the multilayerd OSCC cell coat and polarised expression of cytokeratin and involucrin. There was no evidence for BM, either by immunohistochemistry or by electron microscopy, although OSCC are immunohistochemically positive for collagen type IV and laminin in the 2D cell culture. There were no differences in proliferative activity of the gels with and without fibroblasts. CONCLUSIONS: Carcinoma cell invasion depends on the presence of fibroblasts in the gel indicating the important role of tumor stromal fibro-/myofibroblasts during carcinomic invasion. The absence of a BM does not, per se, imply an invasive tumour growth. Moreover, stratification and terminal differentiation of epithelial tumour cells occur independently of a structural BM.

Basement Membrane↗

PubMed1998

Differential expression of laminin chains in the human major salivary gland.

Laminin represents a macromolecule family. The heterotrimeric isoforms of laminin can be determined by immunohistochemical demonstration of the single chains. The laminin chain heterogeneity of the basement membrane in adult human major salivary glands was evaluated in relation to cellular differentiation of the epithelia and the stromal compartment. Monoclonal antibodies to the laminin alpha1, alpha3 (BM165) chains and epiligrin reacted with the basement membranes of serous and mucous acini and of intercalated, striated and excretory ducts. As evidenced by a double-labelling technique, the alpha2 chain showed a spatial association with the myoepithelium of the acini, whereas the ductal basement membranes containing no myoepithelial cells were negative. Almost exclusively, beta1 chain was detected in acinar basement membrane, beta2 chain whereas in ductal basement membrane. Gamma2 chain is a unique chain belonging to the laminin-5 isoform. It was restricted to the ductal basement membrane. Alpha1, alpha2, beta1, beta2 and gamma1 chains were detected in nerves of salivary tissue and alpha1, alpha3, beta1, beta2 and gamma1 chains and epiligrin in blood vessels. Our results indicate that the acinar ductal unit contains basement membranes with different isoforms, which relate to cell differentiation and cell function.

Adult↗

PubMed1998

Programmed cell death in nodular palmar fibromatosis (Morbus Dupuytren).

The regular loss of cellularity during involutional phase of nodular palmar fibromatosis (Morbus Dupuytren) indicates a regulated process known as programmed cell death (apoptosis). Using the TUNEL method apoptosis-related DNA fragmentation is detected in numerous cells as a characteristic feature of fibromatosis noduli of involutional phase. By means of double labelling technique, alpha-smooth muscle actin immunohistochemistry and TUNEL method for apoptosis, it is demonstrated that the cells which underwent apoptotosis are myofibroblasts. As anticipated, the antidote to apoptosis bcl-2 is not detected in involutional phase, but neither it is evidenced in proliferative phase. Immunohistochemically, Fas/APO-1 is shown to be existent in a very small number of fibroblasts in involutional phase. However, in view of the high number of TUNEL-stained cells a significance in regulating apoptosis in nodular palmar fibromatosis seems improbable. Taking into account that the development of the fibromatosis noduli, the expression of myofibroblast phenotype, basement membrane formation and growth factor expression including TGF beta culminates in involutional phase the initiation of apoptotic cell death can be discussed in relation to these growth factors and matrix protein action and the programmed cell death may be considered as the final step of myofibroblast phenotype evolution.

Apoptosis↗

PubMed1998

Arterivirus PRRSV. Experimental studies on the pathogenesis of respiratory disease.

Pigs were infected with the porcine respiratory and reproductive syndrome virus (PRRSV) by the oronasal route. We studied the development of histological lesions, sites of virus infection and of inflammatory infiltrates by quantitative evaluation of reactive cells. The animals developed a multifocal interstitial pneumonia. Clinical signs of pneumonia were observed from day 7 to 21. In the first stage, an acute alveolitis was found, which was characterised by a hyperplasia of type II pneumocytes within the septa and an accumulation of macrophages in the alveolar spaces. Within 2-4 days p.i., virus infected cells were prominent in lymphatic organs, but their number declined rapidly during the following days. In the following period, the number of virus antigen positive cells increased in the lung. An interesting discrepancy existed between the relatively small number of virus specific cells and the degree of intensive pneumonia. As a first step to analyse mechanisms leading to the induction of pneumonia, we studied transcriptional expression of cytokines and other immunomodulatory molecules by semiquantitative RT-PCR.

Animals↗

PubMed1997

[Basaloid squamous epithelial carcinoma (basaloid-squamous carcinoma) of the mouth floor. Differential diagnosis and response to neoadjuvant chemotherapy].

The basaloid squamous cell carcinoma (BSCC) is a variant of squamous cell carcinoma, having histologically distinctive features and appearing in the oral cavity, upper respiratory tract and esophagus. Histological hallmarks are the presence of a basaloid component in intimate association with squamous cell carcinoma. The basaloid component is characterized by tightly packed nests of cells with scant cytoplasm and hyperchromic nuclei without visible nucleoli and an increased mitosis rate. Basaloid squamous cell carcinoma is said to have a higher malignant potential than common oral squamous cell carcinoma with an increased incidence of regional lymph-node metastases and distant metastases. Our finding of a Ki-67 index of 30% and the immunohistochemical demonstration of p53 protein speaks well for enhanced aggressive biological behavior. The differential diagnosis includes the adenoid cystic, mucoepidermoid, neuroendocrine, adenosquamous and conventional oral squamous cell carcinoma. Because of early dissemination, radical surgical treatment and additional radiation therapy are considered necessary. Our findings indicate that partial clinical and histological tumor regression occurs after systemic neoadjuvant chemotherapy.

Biomarkers, Tumor↗

PubMed1997

Heterogeneity of porcine alveolar macrophages in experimental pneumonia.

The aim of the study was the morphological and the phenotypic characterization of the porcine non-lymphocytic bronchoalveolar lavage (BAL) cell population of unaffected- and intrabronchial with Pasteurella multocida- (P.m.) infected swine using flow cytometry. Three non-lymphocytic cell populations of the porcine bronchoalveolar lavage could be differentiated: (1) large, high autofluorescent cells, (LHC); (2) small, high autofluorescent cells, (SHC); (3) small, low autofluorescent cells, (SLC). In comparison with the control animals, the percentage of the LHC and SHC within the whole non-lymphocytic cell population was decreased, whereas the SLC was significantly enhanced after infection. In order to investigate the phenotype of these cell populations, monoclonal antibodies against porcine antigens (SWC1, SWC3a, MHC class II, 2G6 (against macrophages)) were used. The results showed that the cells of the SLC seem to belong to the granulocytes, whereas the LHC and the SHC are lung macrophages. After the infection of the animals the percentage of the SWC1 positive cells of LHC and SHC were significantly increased, indicating an entrance of more immature macrophages. The percentage of the MHC class II antibody binding cells of all three non-lymphocytic populations was-decreased after infection, indicating a restricted MHC class II dependent antigen recognition in P.m. pneumonia.

Animals↗

PubMed1997

Quantitative evaluation of apoptosis and proliferation in renal cell carcinoma. Correlation to tumor subtype, cytological grade according to thoenes-classification and the occurrence of metastasis.

To analyse growth characteristics of human renal cell tumors, 66 renal cell carcinomas and one oncocytoma were investigated concerning the proliferative activity by immunohistochemical demonstration of the Ki-67 antigen (clone MIB1) and the apoptotic rate using the terminal deoxynucleotidyl-transferase mediated dUTP-fluorescin nick end labelling (TUNEL) method. The TUNEL method indicates DNA double strand breaks considered as a hallmark of programmed cell death (apoptosis). Apoptotic cells were observed in 57 of 67 cases. The apoptotic rate (percentage of stained tumor cells) varied from 0% to 54.1%. GI carcinomas possessed a statistically significant higher apoptotic rate than GII/GIII carcinomas. The proliferation index (percentage of Ki-67 labelled cells) ranged from 0.09% to 22.3%. The well differentiated carcinomas (GI) showed statistically lower proliferative activity than moderate and poorly differentiated carcinomas (GII/GII). The clear cell variant of renal cell carcinoma expressed a higher apoptotic rate than the chromophilic variant. A statistical correlation between apoptosis/proliferation and occurrence of metastasis could not be established. In progression from well to less differentiated renal cell carcinoma the decrease of apoptotic rate, as well as the increase of the proliferative activity, contributes to a rapid tumor growth.

Adenocarcinoma, Clear Cell↗

PubMed1997

Radioimmunodetection of neuroblastoma cells with I-131-radiolabelled antibodies.

The murine anti-neuroblastoma monoclonal antibodies 15/7 and 19/1/4 should be tested for specific radiolocalization of neuroblastoma by immunoscintigraphic imaging of this tumour growing in mice. Radioiodination of both antibodies was done by chloramine-T method resulted in an immunoreactivity of 75%. The calculated specific activity varied from 51.1 to 126.2 kBq/microgram IgG. In each case, about 500 kBq of labeled antibodies were intraperitoneally injected into human neuroblastoma (SK-N-MC, SK-PN-DW and IMR 5) xenografted severe complete immunodeficient (SCID) mice. Whole-body scintigraphy was performed daily by a scintiscanner to localize the tumour site. After last scanning principal organs were removed and their I-131-uptake was determined by measuring the impulse rate. The best scintigrams were done with I-131-19/1/4 at the second day after antibody injection. Radioconjugates were accumulated at highest in the tumour at the third day after application of 15/7 and 19/1/4 with a tumour uptake of 0.4 and 2.2 per cent of injected dose per gram (%ID/g), respectively. The 15/7-moAbs was accumulated approximately 9-fold higher in the SK-N-MC and SK-PN-DW grafts than in principal organs, whereas the tumour/non-tumour-ratio of the 19/1/4 moAb was 3:1. The results indicate the efficacy of these two neuroblastoma antibodies in radiolabelling and their usefulness for tumour imaging of neuroblastoma engrafted SCID-mice.

Animals↗