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Biomedical subjects

A Kummer

Publications and source records attributed to A Kummer.

At least 19 recordsLinked to original sources
PubMed2003

Zinc accumulation in N-methyl-N-nitrosourea-induced rat mammary tumors is accompanied by an altered expression of ZnT-1 and metallothionein.

Zinc is essential for cell proliferation. Several human studies have shown that in breast cancer tissues, zinc concentration expressed on a per tissue weight basis is higher than that in normal breast tissues. However, the mechanisms involved are unknown. N-methyl-N-nitrosourea (MNU)-induced rat mammary tumorigenesis is one of the most widely used rodent mammary tumorigenesis models for studying human breast cancer due to their similarities in hormone dependency, pathogenesis, histological classification, and immunocytochemical markers. This study was to establish if there was an accumulation of zinc in MNU-induced rat mammary tumors and, if there was, to explore the possible mechanisms involved. Sprague-Dawley rats were sham-treated or MNU-treated (50 mg/kg; n = 12) for 100 days. In MNU-induced mammary tumors (mammary tumors), zinc concentration expressed on a per dry weight basis was 12 times of that in normal mammary glands. Moreover, the mRNA level of ZnT-1 (a transporter involved in zinc efflux) in mammary tumors was reduced by 55% as compared with that in normal mammary glands. The mRNA level of Nramp2 (a divalent cation importer) and ZnT-4 (another transporter involved in zinc efflux) was unaffected by MNU-induced mammary tumorigenesis. The mRNA and protein levels of metallothionein (a putative zinc storage protein) in mammary tumors were 1.3 and 3.5 times of that in normal mammary glands, respectively. Collectively, our observations showed that zinc is accumulated in MNU-induced rat mammary tumors and this accumulation is accompanied by an altered expression of ZnT-1 and metallothionein, suggesting that zinc homeostasis might be altered in MNU-induced rat mammary tumorigenesis. Because zinc is essential to cell proliferation and cell proliferation is increased in mammary tumors, zinc accumulation is likely a part of an integrated effort to ensure sufficient zinc supply to sustain tumor growth.

Animals↗
PubMed2001

Smart single-chip gas sensor microsystem.

Research activity in chemical gas sensing is currently directed towards the search for highly selective (bio)chemical layer materials, and to the design of arrays consisting of different partially selective sensors that permit subsequent pattern recognition and multi-component analysis. Simultaneous use of various transduction platforms has been demonstrated, and the rapid development of integrated-circuit technology has facilitated the fabrication of planar chemical sensors and sensors based on three-dimensional microelectromechanical systems. Complementary metal-oxide silicon processes have previously been used to develop gas sensors based on metal oxides and acoustic-wave-based sensor devices. Here we combine several of these developments to fabricate a smart single-chip chemical microsensor system that incorporates three different transducers (mass-sensitive, capacitive and calorimetric), all of which rely on sensitive polymeric layers to detect airborne volatile organic compounds. Full integration of the microelectronic and micromechanical components on one chip permits control and monitoring of the sensor functions, and enables on-chip signal amplification and conditioning that notably improves the overall sensor performance. The circuitry also includes analog-to-digital converters, and an on-chip interface to transmit the data to off-chip recording units. We expect that our approach will provide a basis for the further development and optimization of gas microsystems.

Journal Article↗
PubMed2001

T cell infiltration and MHC I and II expression in the presence of tumor antigens: An immunohistochemical study in patients with serous epithelial ovarian cancer.

OBJECTIVES: Ovarian cancer is a frequent cause of death among women with gynaecologic malignancies despite the introduction of combination chemotherapy. There is therefore a need for new therapeutic strategies for patients with ovarian cancer, such as cellular immunotherapy. In this immunohistochemical study we analysed the expression of three tumor antigens, p53, HER-2/neu and MUC-1 in relation to the expression of major histocompatibility complex (MHC) class I and II on tumor cells, and we searched for the presence of (activated) immune effector cells at the tumor site. STUDY DESIGN: The study was carried out retrospectively in tumor tissue from 29 patients with serous ovarian cancer. Material used had been formalin fixed and paraffin embedded. Material had been obtained from 15 patients at staging laparotomy and from 14 patients during second look or intervention laparotomy. RESULTS: A positive staining for p53 was found in 19/29 (66%) of the tumors, with a high positivity in 13/29 (45%). HER-2/neu and MUC-1 staining was positive in 8/29 (28%) and 21/28 (75%), respectively. Downregulation of MHC class I on tumor cells was found in a minority of the patients, beta-2-microglobin (beta2m) was expressed on tumor cells in all patients. High staining for CD45RO correlated with a high positive staining for granzyme-B (R=0.40, P=0.04) and TIA-1 (R=0.39, P=0.04). A statistically significant better survival in the group with lower stage of disease was found. CONCLUSIONS: As only three out of 29 patients were negative for the tumor antigens p53, HER-2/neu and MUC-1, immunotherapy aiming at all three could serve almost all patients with ovarian cancer. We found that granzyme-B, TIA-1 and CD45RO+ T cells are present in the tumor biopsies, increasing this number by immunotherapy may be beneficial. The immune escape mechanism by MHC class I and beta2m downregulation seems to be of minor importance. Our data support the view that immunotherapy may offer new possibilities with high specificity in ovarian cancer.

Adult↗
PubMed1998

Application of an ELISA-elution assay as a screening tool for dissociation of yolk antibody-antigen complexes.

A modified enzyme-linked immunosorbent assay termed ELISA-elution assay was used as a screening tool to compare the efficiency of eluents for the dissociation of hen yolk immunoglobulin IgY bovine IgG complexes. The potential denaturing effects of the eluents were also monitored. Different buffers (pH 2.3-7.5), containing various types and concentrations of salts (NaCl, (NH4)2SO4 and MgCl2) as well as polyols (ethylene glycol (EG) and glycerol) were compared to the commonly reported glycine x HCl (pH 2.8) buffer and to a commercially available eluent, Actisep. Acidic pH buffers, Actisep and MgCl2 (3.5 M with EG or 4 M without EG) all successfully dissociated IgY from immobilized IgG. However, some denaturation was apparent using MgCl, and, to a lesser extent, Actisep. Furthermore, these same eluents demonstrated a diminished ability for liberating IgG from immobilized IgY(IgG). Information on eluent efficacy obtained by the ELISA-elution assays was applied to selectively isolate lower affinity antibodies for immunoaffinity column chromatography.

Ammonium Sulfate↗
PubMed1997

Influence of standards and antibodies in immunochemical assays for quantitation of immunoglobulin G in bovine milk.

This study reports the influence of using various reference antigens or standards as well as the source of antibody in the immunochemical quantitation of bovine immunoglobulin (Ig) G. Standard curves from analyses by ELISA and radial immunodiffusion were compared for bovine IgG from serum, colostrum, and cheese whey and for the two subclasses IgG1 and IgG2. Also compared were different sources of polyclonal antibodies (antisera from rabbit and sheep or hen yolk) and monoclonal antibodies that had various antibody specificities. The results indicate that IgG1 was a reliable alternative to purified IgG from milk or cheese whey for quantitation of IgG in milk based on ELISA absorbance. Serum IgG, colostral IgG, and IgG2 greatly underestimated milk IgG, regardless of the source of antibody used. Determination of milk IgG by radial immunodiffusion using antisera that were specific for rabbit anti-bovine IgG (H + L) was less dependent on the source of IgG that was used as the standard antigen. However, radial immunodiffusion using subclass-specific antibodies led to inaccurate estimation of IgG in milk unless the quantitation was based on a standard curve for IgG from milk. The Ig from hen yolk were a feasible alternative source of specific antibodies for immunoassay of IgG in bovine milk.

Animals↗
PubMed1996

[Characterization of inflammatory infiltrates in autoimmune cholangitis: an immunohistochemical study].

Autoimmune cholangitis is clinically characterized by cholestasis and serologically by the presence of antinuclear antibodies (ANA) and a lack of antimitochondrial antibodies (AMA). Morphologic characteristics are non suppurative bile duct destruction (NSBDD), ductopenia and occasionally granulomas. The aim of the study was to characterize the inflammatory infiltrate to find about the possible mechanism of bile duct destruction in AIC. Liver biopsy material of ten patients (9 female/1 male, mean age of 45,5 a) with the clinical and serologic features of AIC were evaluated morphologically for the presence of NSBDD, ductopenia and granulomas. The inflammatory infiltrate was characterized immunohistochemically using Ab against CD3 (pan T lymphocytes), OPD 4 (helper T lymphocytes and memory T lymphocytes), CD8 (cytotoxic T lymphocytes), GB4 (activated cytotoxic T lymphocytes), L26 (pan B lymphocytes), CD56 and CD57 (NK/K cells). Lymphocyte subsets were investigated with regard to quantity and distribution within liver tissue. For control ten cases of PBC were also investigated simultaneously. NSBDD was found in five, granulomas in three cases. Portal inflammation was seen in all cases. In 9 cases T cells outweighed B cells. GB4 positive activated cytotoxic T lymphocytes were found within bile duct epithelium in five cases. All these cases showed associated NSBDD. NK/K cells were seen infrequently. Similar findings were observed in the ten cases of PBC. We therefore conclude that bile duct destruction in AIC is mediated by activated cytotoxic T lymphocytes. AIC cannot be differentiated from PBC histologically or by immunomorphology.

Antibodies, Antinuclear↗
PubMed1994

Thymidine labeling index and Ki-67 growth fraction in breast cancer: comparison and correlation with prognosis.

In situ determination of proliferative activity was performed on 184 consecutive primary invasive breast cancers. Methods used were monoclonal antibody Ki-67 in immunohistochemistry and thymidine labeling index. Tumor proliferation correlated between both methods (p = 0.0001). For thymidine labeling index and Ki-67, respectively, significant correlations existed with histologic tumour grade and steroid hormone receptors (Tumor grade: TLI p = 0.0001; Ki-67 p = 0.0001. ER-ICA: TLI = 0.0001; Ki-67 p = 0.014. PgR-ICA: TLI p = 0.0001; Ki-67 p = 0.0008). For thymidine labeling index a significant correlation was demonstrated for overall survival (p = 0.001) and recurrence free survival (p = 0.01). No statistical significance was observed for clinical outcome and Ki-67 (overall survival p = 0.18; recurrence free survival p = 0.1). None of the factors, TLI or Ki-67, was an independent prognostic factor as demonstrated by multivariate analysis.

Breast Neoplasms↗
PubMed1984

[A case of iatrogenic mercury incorporation caused by balloon rupture of a Miller-Abbot tube in intestinal subileus].

A young man admitted with diagnosis of subileus was treated as usual by Miller-Abbot catheter with a mercury-filled balloon at the distal tip. During treatment of this patient the mercury-filled balloon ruptured, but no signs of poisoning occurred despite a blood mercury level 4 times higher than normal. In contrast to one fatal case described in the literature, the present case followed a course without signs of mercury intoxication under treatment with Dimaval (Na-2,3,-dimercapto-1-sulfanat).

Adult↗
PubMed1979

The effects of chronic middle ear effusion on speech and language development -- a descriptive study.

In this study, the speech and language skills of children with histories of chronic middle ear effusion were analyzed. Forty-seven children between the ages of one year eleven months and five years five months were given a battery of speech and language tests in the course of a diagnostic evaluation. All the children had been referred to speech pathology by a physician because of a suspected communication disorder. All subjects had histories of three or more episodes of middle era effusion, with the first episode occurring prior to 18 months of age. All medical records were checked and in-depth case histories were obtained in order to rule out other possible complicating factors that might have contributed to a speech and language delay. The results of this study revealed essentially age-appropriate receptive language skills in this group of children. Expressive language and articulatory skills were significantly below chronological age level expectation, indicating the possible serious effects of chronic middle ear effusion on speech and language development.

Child, Preschool↗