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Biomedical subjects

M Seifert

Publications and source records attributed to M Seifert.

At least 37 records · Page 2Linked to original sources
PubMed2000

Inhibition of keratinocyte apoptosis by IL-15: a new parameter in the pathogenesis of psoriasis?

Keratinocytes (KC) are important source of and targets for several cytokines. Although KC express IL-15 mRNA, the functional effects of IL-15 on these epithelial cells remain to be dissected. Investigating primary human foreskin KC and HaCaT cells, we show here by semiquantitative RT-PCR and flow cytometric analysis that both translate IL-15 and IL-15R mRNA and express IL-15 and IL-15Ralpha protein on the cell surface, suggesting that human KC can employ IL-15 for juxtacrine signaling. While IL-15 exerted no significant effect on KC proliferation and IL-6 or IL-8 secretion, IL-15 inhibited both anti-Fas and methylcellulose-induced KC apoptosis in vitro. This is in line with the recognized potent anti-apoptotic effects of IL-15. IL-2, whose receptor shares two components with the IL-15R, failed to inhibit KC apoptosis. Together with the role of IL-15 in sustaining chronic immune reactions, this invited the question of whether a reduction of KC apoptosis by IL-15 may be involved in the pathogenesis of psoriasis, a chronic hyperproliferative inflammatory skin disease characterized by abnormally low KC apoptosis in the epidermis. Remarkably, compared with nonlesional psoriatic skin and skin of healthy volunteers, lesional psoriatic epidermis showed high IL-15 protein expression in the epidermis and enhanced binding activity for IL-15. Therefore, antagonizing the inhibitory effects of IL-15 on KC apoptosis deserves exploration as a novel therapeutic strategy in psoriasis management.

Apoptosis↗
PubMed2000

Potential of allospecific gene-engineered T cells in transplantation gene therapy: specific T cell activation determines transgene expression in vitro and in vivo.

T lymphocytes, regardless of their specificity, are considered key targets for genetic modification in the treatment of inherited or acquired human diseases. In this study, we generated Lewis T cell lines specific for Dark Agouti rat alloantigens and tested the potential of allospecific T lymphocytes as carriers of genes encoding therapeutic proteins in transplantation gene therapy. These allospecific T lymphocytes were successfully, stably transduced with enhanced green fluorescent protein (EGFP) by an Mo-MuLV-based retrovirus vector. A novel gene delivery protocol was utilized, resulting in nearly 100% EGFP-expressing T cells. This approach enabled tracking of allospecific transduced T cells in vivo and illustrates their transgene production by fluorometric determination after ex vivo isolation. Quantitation of EGFP transgene expression was used to determine the influence of T cell receptor-specific activation on transgene regulation. A strict positive correlation between activation state and expression level was detected in vitro and in vivo. The activation-induced increase in transgene expression could be blocked by interference with T cell activation signaling pathways by cyclosporin A, anti-CD4 MAb, or CTLA4-Ig. These data provide strong evidence that direct or indirect effects caused by activation-induced transcription factors are crucial in transgene upregulation. Allospecific activation in spleens, lymph nodes, and transplanted grafts can be considered as antigen-specific targeting strategy. This activation might be useful in expressing therapeutic proteins such as TGF-beta or IL-10 specific to these sites. T lymphocyte priming and activation might be prevented or altered by modification of the local microenvironments, thereby exerting a therapeutic influence on acute and chronic graft rejection processes.

Abatacept↗
PubMed2000

The antipsoriatic activity of IL-10 is rather caused by effects on peripheral blood cells than by a direct effect on human keratinocytes.

IL-10 is a promising candidate for the treatment of cutaneous disorders. Antipsoriatic efficacy of systemic IL-10 treatment has been already demonstrated. This includes histomorphological changes in the epidermis, suggesting effects on keratinocytes. However, less is known about direct effects of IL-10 on this cell population, although effects are likely since IL-10 receptor expression on keratinocytes has been demonstrated recently. Therefore we analysed the effects of IL-10 on keratinocytes in vitro, using concentrations of human recombinant IL-10 corresponding to those detectable in plasma during therapy. Proliferation, cytokine formation (IL-6, IL-8, IL-1ra), and expression of surface molecules (MHC class I and II, costimulatory molecules CD80 and CD86, CD29, CD54, CD95) were measured in stimulated and unstimulated cells. Although stimulation influenced the expression levels of certain surface markers, no or only slight effects of IL-10 were found. In contrast considerable inhibitory effects of IL-10 on surface molecule expression and cytokine secretion by peripheral blood human monocytes were observed. Our results suggest that the antipsoriatic activity of IL-10 is rather caused by modulatory effects on circulating immune cells, which subsequently might infiltrate the skin, than by direct effects on human keratinocytes. Considering the remarkable antipsoriatic activity of IL-10 and the observation that IL-10 seem to act on peripheral blood mononuclear cells but not on keratinocytes provide further evidence that circulating immune cells play a key role in the pathology of psoriasis. Finally, our results argue against the value of IL-10 therapy in dermatoses strictly limited to keratinocyte involvement.

Antigens, CD↗
PubMed2000

Alimentary lead intake of adults in Thuringia/Germany determined with the duplicate portion technique.

The daily lead intake in Germany in 1996 was studied using the duplicate portion technique. The study was carried out in four towns in Thuringia (Jena, Ronneburg, Rositz, Steudnitz), in which volunteers collected all foods and beverages over 7 consecutive days. The mean lead content of consumed food and beverages was 66 and 55 microg/kg dry matter for women and men, respectively; the average lead intake was 19 microg/day for both, women and men. In relation to body weight (b.w.) the intake for women was 283 ng/kg and for men 242 ng/kg b.w. These values are well below the WHO limit. An oral lead exposure of the adult population of Thuringia/Germany can be excluded.

Adult↗
PubMed2000

One-stage Soave pull-through for Hirschsprung's disease: a comparison of the transanal and open approaches.

PURPOSE: The authors reviewed their experience using the transanal Soave technique, to determine (1) if it offers any advantages over the standard open approach and (2) whether routine laparoscopic visualization is necessary. METHODS: The case reports of 37 consecutive children less than 3 years old undergoing Soave pull-through were reviewed. Patients were excluded from analysis if they had total colon disease or had a previous colostomy. The patients were divided into 3 groups: open Soave (OS, n = 13), transanal Soave with routine laparoscopic visualization (LVS, n = 9), and transanal Soave with selective laparoscopy or minilaparotomy (TAS, n = 15). Cost was calculated based on hospital stay, operating room time, and use of laparoscopic equipment. RESULTS: In the TAS group, suspicion of a longer segment led to the selective use of laparoscopy with or without biopsy in 2 children, and the use of a small umbilical incision for mobilization of the splenic flexure in 2. There were no differences among groups with respect to age, weight, gender, transition zone, operating time, blood loss, intraoperative complications, enterocolitis, or stricture or cuff narrowing. Hospital stay was significantly longer in the OS group (median, 7 days; range, 3 to 47) than the LVS (median, 1; range 1 to 6) or TAS (median, 1, range, 1 to 3) groups. Cost (in thousands of dollars) was also higher in the OS group (median, 6.9; range, 3.9-25.7) than the LVS (median, 3.9; range, 3.6 to 6.4) or TAS (median, 3.4; range, 2.2 to 9.4) groups. Repeat surgery was necessary for 4 OS patients: 2 adhesive small bowel obstructions (1 of whom died), 1 twisted pull-through, and 1 recurrent aganglionosis. Three TAS patients required repeat surgery: 1 twisted pull-through, 1 anastomotic leak, and 1 cuff narrowing. CONCLUSIONS: These data suggest that the transanal pull-through is associated with a significantly shorter hospital stay and lower cost than the open approach, without an increased risk of complications. Because there is no intraabdominal dissection, there probably is a lower incidence of adhesive bowel obstruction. Routine laparoscopic visualization or minilaparotomy is not necessary but should be used in children who are at higher risk for long segment disease.

Child, Preschool↗
PubMed2000

Attitude towards prophylactic surgery and effects of genetic counselling in families with BRCA mutations. Austrian Hereditary Breast and Ovarian Cancer Group.

The intent of this study was to evaluate the effect that an awareness of being a BRCA1 or BRCA2 mutation carrier has on the attitude towards prophylactic surgery and on developing depression symptoms. Thirty-five families were selected on the basis of previously detected BRCA1 or 2 mutations and 90 family members were given the appropriate questionnaires. Prophylactic mastectomy (PM) was considered by 21% of the Austrian mutation carriers (29% affected and 8% non-affected carriers). The majority of affected and non-affected carriers expected PM to impair the quality of their life. Fifty per cent would undergo prophylactic oophorectomy (53% affected and 46% non-affected carriers). The self-rating depression scale indicated that following mutation result disclosure the depression scores of carriers decreased (40 baseline vs 38 after result disclosure, P = 0.3), whereas, for non-carriers, scores increased (36 baseline vs 40 after result disclosure, P = 0.05). We conclude that information about carrier status is not associated with increased depression symptoms in mutation carriers. In non-carriers, depression scores increased slightly, probably reflecting survivor guilt. The option of having PM was associated with a negative impact on the quality of life and was declined by the majority of Austrian mutation carriers.

Adult↗
PubMed2000

Single-agent gemcitabine as second- and third-line treatment in metastatic breast cancer.

In the present study, 25 patients with breast cancer pretreated with one or two anthracycline-based regimens for visceral metastases were enrolled. Patients were treated with gemcitabine 1250 mg/m2 on days 1, 8 and 15, q28d. Nine patients received gemcitabine as second-line treatment, whereas 16 patients received gemcitabine as third-line cytotoxic treatment, respectively. In the second-line setting, two (22%) patients gained PR (RR 22%) and four (44%) patients experienced SD (P=0.2), respectively. In the third-line-setting, one (6%) patient gained CR, one patient PR (6%) and four patients (25%) SD, respectively, resulting in a response rate (RR) of 12%. In the second-line-setting, median time to progression was 5.1 +/- 4.0 months (range: 1.6-13.9) versus 3.5-2.5 months (range: 1.3-10.4) in the third-line-setting. Median overall survival was 12.6 +/- 9.1 months (range: 3.9-30.8) versus 7.5 +/- 6.7 months (range: 2.0-26.0), respectively. Overall, no patient experienced treatment limiting toxicities. We conclude from the present study that gemcitabine induced an overall RR of 16% following prior treatment with anthracyclines. However, median time to progression and median overall survival were limited. In the search for efficacious treatment of patients with metastatic breast cancer, gemcitabine constitutes a valid tool in anthracycline-resistant disease and thus might represent a valuable option for combination chemotherapy in controlled trials in this condition.

Journal Article↗
PubMed2000

Paclitaxel-containing high-dose chemotherapy in high-risk breast cancer patients.

Despite standard-dose adjuvant chemotherapy, the prognosis for patients with breast cancer and extensive axillary lymph node involvement at diagnosis is poor. The efficacy of a paclitaxel-containing, high-dose chemotherapy protocol in 21 high-risk breast cancer patients is assessed. After standard-dose chemotherapy followed by peripheral blood stem cell (PBSC) mobilization, high-dose therapy with paclitaxel, carboplatin, and cyclophosphamide and CD34-selected PBSC rescue was given. Hematologic reconstitution after high-dose therapy was rapid. Main toxicity included diarrhea grade I or II in about half of the patients and infections were observed in 19%. Five-year probabilities for relapse and failure-free survival were 32% and 62%, respectively. High-dose consolidation with paclitaxel, carboplatin, and cyclophosphamide achieves a high failure-free survival in patients with high-risk breast cancer with acceptable toxicities and stable, long-term hematopoietic reconstitution. Evaluation of the benefit of high-dose therapy in these patients in larger prospective, randomized trials is warranted and currently under way.

Adult↗
PubMed1999

CAPN 8: isolation of a new mouse calpain-isoenzyme.

Recent molecular biological approaches indicate that calpain, also named CANP for calcium-activated neutral protease and originally characterized as an intracellular cytoplasmatic nonlysosomal cysteine protease that requires calcium ions for activity, constitutes a large superfamily consisting of ubiquitous and tissue specific homologues, which are widely distributed in cells of various organisms from human to fungus. Due to the increasing number of substrates along with the involvement of calpain isoenzymes in mammalian diseases, especially in malignancies, members of the calpain superfamily seem to be important biomodulators in physiological as well as pathological cell function. Here we report the characterisation of a new calpain, named CAPN 8 with a different C-terminal domain, implicating a putative new regulatory mechanism. Northern blot analysis revealed an ubiquitous expression with different RNA levels in all tissues examined. Highest levels were found in brain, kidney, and digestive tract, suggesting a specific regulatory function of CAPN 8 in these tissues.

Amino Acid Sequence↗
PubMed1999

Estrogen replacement therapy in women with a history of breast cancer.

Estrogens are known as potent mammary mitogen substances and are the major stimulus for the growth of hormone-dependent tumors and clearly implicated in the pathogenesis of breast cancer. Therefore it is a general belief that hormone replacement therapy (HRT) after breast cancer will increase the risk of developing recurrences, though there are no clear data available to support this suggestion. No prospective study with a large number of patients and a long treatment period was performed concerning this issue. On the other hand it may not be justifiable to withhold hormone replacement therapy from low-risk patients after menopause, knowing the benefits of this therapy concerning osteoporosis and cardiovascular advantages. Nevertheless, until appropriate clinical trials help to resolve this problem, non hormonal alternatives constitute the standard of care. One possible approach is to treat menopausal women who have had breast cancer symptomatically and avoid ERT unless absolutely necessary. The risk of cardiovascular diseases can be reduced with lifestyle. Tamoxifen has a beneficial effect on serum lipids and the intake for 5 years leads to a 50% reduction in the incidence of fatal myocardial infarction and a decrease in morbidity associated with ischaemic heart disease. Low doses of progestogen is effective for menopausal hot flushes. Tibolone reduces vasomotoric symptoms such as hot flushes and offers benefit on osteoporosis and has shown a significant reduction in high-density lipoprotein cholesterol. Whether replacing of estrogens is safe for patients after breast cancer remains uncertain. There is a need for a large controlled clinical trial to evaluate the safety and advantages of long time estrogen replacement in women treated for breast cancer.

Breast Neoplasms↗
PubMed1999

Crosstalk between keratinocytes and T lymphocytes via Fas/Fas ligand interaction: modulation by cytokines.

Apoptosis mediated by Fas/FasL interaction plays an important role during many inflammatory skin disorders. To estimate whether the expression of FasL, the ligand for Fas, might be regulated by cytokines we stimulated primary human keratinocytes with several pro- and anti-inflammatory cytokines. Keratinocytes cultured to subconfluence expressed FasL constitutively. Cells stimulated with the proinflammatory cytokines IL-1beta, TNF-alpha, IFN-gamma, and IL-15, respectively, increased significantly their intracellular as well as cell surface-bound FasL expression in a time- and dose-dependent manner. This cytokine-induced FasL expression was dependent on new protein synthesis. Despite enhanced expression of cell surface-bound FasL, no release of soluble FasL was measured in the cell supernatants determined by ELISA. Stimulation of the cells with IL-6, IL-10, IL-12, TGF-beta1, and GM-CSF did not modulate the constitutive FasL expression, but IFN-gamma-mediated FasL up-regulation was significantly diminished by IL-10 and TGF-beta1, respectively. Up-regulation of FasL on IFN-gamma-stimulated keratinocytes led to increased apoptosis within monolayers cultured for 48 h. Moreover, coculture experiments performed with Fas+ Jurkat T cells revealed that enhanced FasL expression on IFN-gamma-stimulated keratinocytes induced apoptosis in cocultured T cells, demonstrating that up-regulated FasL was functionally active. In summary, our data suggest the important regulatory role of cytokine-controlled Fas/FasL interaction in the cross-talk between keratinocytes and skin-infiltrating T cells for maintenance of homeostasis in inflammatory skin processes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Expression of calpain I messenger RNA in human renal cell carcinoma: correlation with lymph node metastasis and histological type.

Calpain, also named CANP (for calcium-activated neutral protease), is an intracellular cytoplasmatic non-lysosomal cysteine endopeptidase that requires calcium ions for activity. Many substrates of the calpain isoenzymes, such as the transcription factors c-Fos and c-Jun, the tumor supressor protein p53, protein kinase C, pp60c-src and the adhesion molecule integrin, have been implicated in the pathogenesis of different human tumors, suggesting an important role of the calpains in malignant diseases. We now report differential expression of the calpain I gene (CL I) in a variety of tumors, extending our study to a larger series of renal cell carcinomas. Using Northern-blot analysis, we studied calpain I expression in 30 renal cell carcinomas as compared with matched healthy tissues. Tumor samples were classified according to their histological type: 21 clear cell carcinomas, 4 chromophobe carcinomas, 3 papillary carcinomas and 2 oncocytomas. In renal tumor samples, calpain I gene mRNA was expressed at highly variable levels, significantly depending on the different histological types. Moreover, there was a correlation of higher calpain I expression with increased malignancy: within the clear cell carcinoma subset, tumor samples with advanced nodal status (N1 and N2) showed a significantly higher calpain I expression than tumors without metastasis to regional lymph nodes. Our data suggest an important role of calpain isoenzymes in carcinogenesis and tumor progression.

Biomarkers, Tumor↗
PubMed1999

The yeast two-hybrid system reveals no interaction between p73 alpha and SV40 large T-antigen.

SV40 and/or DNA sequences indistinguishable from SV40 have been detected in several types of human tumours. The oncoprotein of Simian virus 40, SV40 large T-antigen (Tag), is known to bind and inactivate tumour suppressor proteins, such as members of the retinoblastoma family and p53, thereby promoting cell transformation. In this study, we used the yeast two-hybrid system to investigate whether the Simian virus 40 (SV40) large T-antigen is able to interact with p73, a noval discovered putative tumour suppressor, that is homologous both structurally and functionally to p53. The yeast two-hybrid system is a genetic method to detect protein-protein-interactions in vivo. Our results suggest that the SV40 large T-antigen is not able to bind p73 in yeast although both proteins are expressed in the transformed yeast strain as was shown by western blot analysis.

Animals↗
PubMed1999

Characterization of neutralizing anti-pre-S1 and anti-pre-S2 (HBV) monoclonal antibodies and their fragments.

Single-chain Fv fragments (scFv) were generated from two murine monoclonal antibodies directed to the neutralizing epitopes of the pre-S1 and pre-S2 region of hepatitis B virus, respectively, using different assembly cloning strategies. The scFv fragments were solubly expressed in E. coli. Dissociation constants were in the nanomolar range for all forms (whole IgG antibodies, Fab fragment and scFv fragments). The epitopes of both antibodies were mapped using solid phase peptide synthesis on continuous cellulose membranes and turned out to be linear determinants. The minimal epitope for the anti-pre-S2 antibody 1F6 was identified to be DPRVRGLYF (amino acid 133-141 of the pre-S region). For the anti-pre-S1 antibody MA 18/7 the minimal epitope proved to be the hexamer LDPAFR (amino acid 30-35 of the pre-S region). Complete substitutional analyses as well as truncation experiments revealed key residues for these antibody-antigen interactions. On the basis of those results we used computer-assisted modeling techniques to suggest models for both antibody-peptide interactions providing insight into the structural basis of these molecular recognitions.

Amino Acid Sequence↗
PubMed1999

Prognostic significance of mutations in the p53 gene, particularly in the zinc-binding domains, in lymph node- and steroid receptor positive breast cancer patients. Austrian Breast Cancer Study Group.

The aim of our study was to evaluate if p53 mutations, especially those in the L2/L3 domains of the p53 gene, add prognostic information for node-positive and steroid receptor positive breast cancer patients. Two hundred and five tumour samples from a randomised clinical trial of 596 lymph node- and steroid receptor positive breast cancer patients were included. All patients had been randomly allocated to receive 20 mg of adjuvant tamoxifen (TAM) daily for 2 years or TAM plus one cycle of low-dose, short-term chemotherapy. For detection of p53 mutations we used in vitro amplification by polymerase chain reaction and consecutively performed temperature gradient gel electrophoresis (PCR-TGGE) and direct sequencing. We found p53 mutations in 42/205 (20%) cases: 16/42 (38%) p53 mutations occurred within the L2/L3 domains of the p53 gene, and 26/42 (62%) outside the L2/L3 domains. p53 mutation served as a statistically significant parameter in predicting disease-free survival in univariate (P = 0.02) and multivariate (P = 0.009) analysis. For overall survival, no significant differences were observed. Patients with tumours that had p53 mutations within the L2/L3 domains of the gene showed no significant difference to those with mutations outside the L2/L3 domains for disease-free survival. For overall survival, mutations in the L2/L3 domains showed a marginally significant difference (P = 0.05) in multivariate analysis, but not in univariate analysis (P = 0.13). We conclude that mutation in the L2/L3 domains of the p53 gene is not an independent prognostic indicator of disease outcome for patients suffering from breast cancer with lymph node metastases and positive steroid receptors.

Adult↗
PubMed1999

[Extraovarian peritoneal serous papillary carcinoma: an unusual surgical case].

The extraovarian peritoneal serous papillary carcinoma (EPSPC) is a multicentric peritoneal tumor with minimal or absent involvement of the ovaries. The actual treatment regimen consists of a cytoreductive surgery followed by a combination chemotherapy. Few studies have compared outcome of EPSPC to papillary serous ovarian cancer (PSOC). Several authors have documented similar clinical behavior between EPSPC and PSOC, but this finding has not been universal. A 64-year-old female patient with symptomatic gall stone disease underwent elective laparoscopic cholecystectomy. Unexpectedly we found some uncommon small nodular structures on the serosa of the right colon. The histological findings suggested a poorly differentiated peritoneal serous papillary carcinoma. Biopsies of both ovaries showed no signs of tumor infiltration and the diagnosis of EPSPC was established. After surgery, a combination chemotherapeutic regimen with carboplatin and cyclophosphamid was given. Laparoscopic reassessment 7 months after the first procedure showed no tumor. 3 identical cycles completed chemotherapy. Normal ovaries and no other tumor sites were found in a final laparoscopic look after 11 months.

Cystadenocarcinoma, Papillary↗