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K M Müller

Publications and source records attributed to K M Müller.

At least 91 records · Page 5Linked to original sources
PubMed1999

Selectively infective phage (SIP) technology: scope and limitations.

We review here the selectively infective phage (SIP) technology, a powerful tool for the rapid selection of protein-ligand and peptide-ligand pairs with very high affinities. SIP is highly suitable for discriminating between molecules with subtle stability and folding differences. We discuss the preferred types of applications for this technology and some pitfalls inherent in the in vivo SIP method that have become apparent in its application with highly randomized libraries, as well as some precautions that should be taken in successfully applying this technology.

Bacteriophage M13↗
PubMed1999

The APC protein binds to A/T rich DNA sequences.

The tumor suppressor protein APC (Adenomatous Polyposis Coli) is localized in the cytosol and in the nucleus. In this study, we demonstrate that the nuclear APC protein level is high in cells in the basal crypt region of the normal colorectal epithelium. Strikingly, the APC protein staining resembles the staining pattern of a nuclear proliferation marker. As a first step towards a possible role of the nuclear APC protein, we provide data showing the direct interaction of the nuclear APC protein with DNA. A nuclear APC isoform precipitates with matrix-immobilized DNA. Vice versa, the immunoprecipitation of APC from nuclear lysates results in co-precipitation of genomic DNA. Using recombinant APC fragments we mapped three DNA binding domains: one within the beta-catenin binding and regulatory domain, and two in the carboxyterminal third of the APC protein. All these three domains contain clusters of repetitive S(T)PXX sequence motifs that were described to mediate the DNA interaction of many other DNA binding proteins. In analogy to S(T)PXX proteins, the APC protein binds preferentially to A/T rich DNA sequences rather than to a single DNA sequence motif.

Adenomatous Polyposis Coli↗
PubMed1999

[Lymphomatoid granulomatosis: differential diagnosis and therapy].

CASE REPORT: In a 59-year-old patient presenting with fever, malaise and pulmonary masses the diagnosis of lymphomatoid granulomatosis was established histologically by open lung biopsy. Despite an immunosuppressive therapy with cyclophosphamide and prednisolone partial remission was achieved for no longer than 8 weeks. Five months later he died in a septic condition. CLINICAL PRESENTATION: In our paper we discuss the present case and give a short review of the literature. Lymphomatoid granulomatosis is a rare angiocentric and angiodestructive condition which shows characteristics of both a lympho-proliferative and a necrotizing aseptic granulomatous process. It involves most frequently lungs, central nervous system and skin. The clinical course is variable, but mortality is high. Malignant lymphoma is a frequent fatal complication. Immunologic dysfunction and EBV-associated B-cell transformation seem to play an important role in the pathogenesis of this disease. TREATMENT: As optimal therapy is unknown, attempts have been made with immunosuppressive therapy according to the Fauci scheme as well as with combined chemotherapy according to the CHOP scheme and radiation. In a recent trial, promising results have been reported for interferon alpha 2b.

Antineoplastic Agents↗
PubMed1999

Histologic types of lung carcinoma and age at onset.

BACKGROUND: Previous research has demonstrated that adenocarcinoma is the leading cell type among patients with early age onset lung carcinoma. An increase in adenocarcinoma at the expense of squamous cell carcinoma in general was observed in recent years and may be due to the smoking of filtered cigarettes. METHODS: To rule out whether shifts in smoking patterns or other etiologic factors are responsible for the high rates of adenocarcinoma in young patients, personal interviews regarding smoking, occupation, and family history of cancer were conducted in 251 young patients (age < or =45 years) and 2009 older patients (ages 55-69 years) with histologically confirmed lung carcinoma from selected study clinics in Germany between 1990 and 1996. RESULTS: Young male patients were found to have significantly more adenocarcinomas (41%) than older male patients (28%), whereas adenocarcinomas were dominant in young and older women (43% and 47%, respectively). Because smoking patterns were different between young and older patients, the authors stratified for comparable levels of smoking exposure. Histology did not differ in never smokers (dominance of adenocarcinomas in both age groups) and in male heavy smokers (dominance of squamous cell carcinomas in both age groups), whereas young male low dose smokers showed significantly more cases of adenocarcinoma than older low dose smokers. A family history of lung carcinoma was significantly higher in young patients compared with older patients, but no association with histologic type was observed. CONCLUSIONS: The results of the current study show that differences in the histologic type of lung carcinoma based on age at onset can be explained in part by differences in smoking patterns. However, there still are unknown factors that appear to favor the development of adenocarcinoma in the young.

Adenocarcinoma↗
PubMed1999

Anti-proliferative activity of protein kinase C in apical compartments of human colonic crypts: evidence for a less activated protein kinase C in small adenomas.

The protein-kinase-C (PKC) family of iso-enzymes regulates mitogenic signal transduction in colorectal-cell lines. Its function in human colonic mucosal proliferation is controversial. Our study investigated the role of PKC with regard to proliferation and changes of PKC iso-enzyme expression in colonic biopsies compared with small adenomas. In short-term tissue-culture experiments of colonic mucosal biopsies, we found reduced S-phase labeling in the 2 apical compartments of longitudinally sectioned crypts when PKC was activated by 200 nM of the phorbol ester TPA (n = 8). Thus, PKC inhibited growth of differentiated colonocytes which may influence cell homeostasis in colonic crypts. Furthermore, we have determined the expression of PKC alpha, -beta1, -beta2, -delta and -epsilon in colonic adenomas smaller than 1 cm in diameter of 18 patients and found a significant increase of PKC alpha in the cytosolic fraction and decreased membrane levels of PKC beta2 in adenomas compared to normal, neighboring mucosa while protein levels of PKC beta1, -delta and -epsilon were not altered. Moreover PKC delta but not PKC alpha mRNA expression was significantly lowered in adenoma tissue in 7 patients, as determined by ribonuclease-protection analysis. Changes in the regulation patterns of PKC isoforms suggest a decreased activation state of PKC even in small adenomas. This is compatible with an anti-proliferative function of PKC serving to protect mucosa from expanding mutated cells.

Adenoma↗
PubMed1999

Urokinase-type plasminogen activator inhibits alpha 4 beta 1 integrin-mediated T lymphocyte adhesion to fibronectin independently of its catalytic activity.

The urokinase-type plasminogen activator (u-PA)/plasmin system plays an important role in promoting cell migration and invasion, an effect which is largely ascribed to the proteolytic activity of these enzymes. We investigated whether u-PA modulates integrin-dependent T lymphocyte migration and adhesion on fibronectin independently of its plasminogen activator function. Here we report that u-PA reduced the spontaneous and phorbol 12-myristate 13-acetate-induced migration of peripheral blood T lymphocytes on fibronectin by 20-50%, decreased the T lymphocyte and alpha4beta1(+)/alpha5beta1(+) K562 cell adhesion on fibronectin by 30-40%, and completely suppressed integrin alpha4beta1-dependent T lymphocyte and alpha4beta1(+)/alpha5beta1(+) K562 cell adhesion to the LDV-containing 40-kDa fibronectin fragment. The u-PA receptor was not essential for this effect. In contrast, adhesion of alpha4beta1(-)/alpha5beta1(+) K562 cells to an RGD-containing fibronectin fragment was unaffected. A recombinant protein comprising the N-terminal fragment of u-PA, but lacking its proteolytic domain, had the same inhibitory effect. Decreased adhesion was neither associated with a diminished cell surface expression of alpha4beta1 nor with a suppression of alpha4beta1 ligand-binding function. Our results demonstrate that u-PA inhibits alpha4beta1- but not alpha5beta1-mediated lymphocyte/leukocyte adhesion to fibronectin independently of its proteolytic activity. This finding provides additional evidence that matrix proteinases may participate in cell adhesion and migration control independently of their matrix-degrading activity.

Catalysis↗
PubMed1999

[Peritoneal mesothelioma--incidence and etiology].

A total of 70 malignant and 4 benign peritoneal mesotheliomas were diagnosed by the German Mesothelioma Registry between 1992 and 1998. Malignant mesotheliomas developed mainly in men (55/70); only one man had a benign peritoneal alteration. Age at first diagnosis of malignant mesotheliomas is about 59 years; the women are on average 4 years younger than the men. Mean survival time ranges about 1 year; in 6 of 38 patients longer survival times of up to 7 years are known. The epitheloid subtype predominates, but no effect on survival time is noticed. The percentage of patients with combined asbestos-associated lung fibrosis is higher than that for pleural mesotheliomas; these patients become ill about 6.5 years earlier. The latency period is 36 years on average. For most patients asbestos exposure is related to their occupation mainly in metal industries, asbestos industries, and in the building trade. There is no evidence for an induction of benign peritoneal alterations by asbestos dust.

Asbestos↗
PubMed1999

[German-Latvian cooperation in the pathology specialty].

In the field of pathology there have been very close connections since the beginning of this century and a regular exchange of ideas between the pathologists of Latvia and Germany. Pathologists of Latvia were members of the German Association of Pathology. The stages of political changes in Europe very much influenced the exchanges of ideas. The following presentation will outline the activities and personalities in the sector of pathology in the time period until 1918--time of the Russian Czar Empire--, during the National State of Latvia and the Second World War (1918-1940), then during the Russian occupation of Latvia (1944-1991) and also the new time period after the political changes. Evaluated in this presentation the yearly support of the Baltic/German Symposiums, assisted by the IAP, which in addition to the activities in pathology also promote and encourage many personal contacts and friendships.

Germany↗
PubMed1999

Expression of vascular endothelial growth factor in diffuse malignant pleural mesothelioma.

Angiogenesis is an important part of normal and pathological processes, including tumour growth, metastasis, inflammation and wound healing. VEGF is the best known angiogenic factor, implicated in tumour-associated microvascular hyperpermeability and carcinogenesis. We investigated 103 malignant pleural mesotheliomas, analysing the expression of vascular endothelial growth factor using immunohistochemistry and in situ hybridization. The grade of microvessel density was assessed with the aid of anti-factor-VIII antibodies. An increased expression of VEGF was found in biphasic and epithelioid mesotheliomas, correlating in a statistically significant manner (P<0.042). In situ hybridization confirmed the specificity of VEGF mRNA expression. There was a robust correlation between VEGF expression and increased microvessel density (P<0.001), and positive mesotheliomas had significantly higher microvessel densities than negative specimens. There was also a significant correlation between microvessel density and histological pattern. As growth pattern tended towards biphasic and sarcomatoid mesotheliomas the density of micovessels decreased (P<0.05).

Adult↗
PubMed1999

Congenital alveolar proteinosis caused by a novel mutation of the surfactant protein B gene and misalignment of lung vessels in consanguineous kindred infants.

UNLABELLED: Congenital alveolar proteinosis and misalignment of lung vessels are rare disorders. We report on five infants of consanguineous kindred. All infants were delivered at term after uneventful pregnancies. Shortly after birth they developed respiratory failure and severe persistent pulmonary hypertension. All died despite intensive care. Lung tissue of two infants was studied. Histological examination revealed combination of alveolar proteinosis and misalignment of lung vessels in one patient, alveolar proteinosis in the other. Immunostaining demonstrated surfactant protein B (SP-B) deficiency in both patients' lungs. In a further sibling, analysis of broncho-alveolar lavage fluid showed decreased surfactant protein. PCR and direct sequence analysis of the SP-B gene revealed three novel mutations. One of them, a single base deletion, shifts the reading frame at amino acid 122 and creates a premature termination of translation in exon 6. No mature SP-B protein is produced. CONCLUSION: Surfactant protein B deficiency caused by mutations of the respective gene and misalignment of lung vessels can concur. Both diseases may have a pathogenetic factor in common.

Blood Vessels↗
PubMed1999

Intracellular distribution of beta-catenin in colorectal adenomas, carcinomas and Peutz-Jeghers polyps.

The interaction of the adenomatous polyposis coli (APC) tumor-suppressor protein and the intracellular cell-adhesion protein beta-catenin is crucial for the development of colorectal tumors. Since functional nuclear complexes of beta-catenin with transcription factors have been identified recently, the knowledge of level and distribution of beta-catenin in sporadic colorectal tumors will give important insights into the intracellular mechanism of sporadic colorectal tumor initiation and progression. In contrast to the familiar adenomatous polyposis syndrome and to the majority of sporadic colorectal tumors, Peutz-Jeghers (PJ) syndrome is not caused by mutations in the APC gene. Since PJ syndrome is an inherited disease with an increased risk for gastrointestinal adenocarcinoma, whether beta-catenin plays a similarly important role for the development of PJ polyps should be further investigated. For these reasons we analyzed the distribution of beta-catenin in a total of 60 sporadic colorectal tumors at different stages of progression and in 6 PJ polyps. In addition to the localization at the cell-to-cell border membranes, fluorescence immunohistochemistry revealed a nuclear accumulation of beta-catenin in single tumor cells of 10/14 small adenomas with mild dysplasia and in 14/16 adenomas with moderate dysplasia. Further tumor progression is accompanied by an expansion of cells with increased level of nuclear and cytoplasmic beta-catenin. These cells were observed in 5/16 adenomas with moderate dysplasia and in 15/15 adenomas with severe dysplasia. In all adenocarcinomas investigated, as well as in the corresponding lymph node metastases, a sub-population of tumor cells exhibited a remarkably increased level of beta-catenin within the entire cytoplasm and the nucleus. In contrast to the situation in sporadic colorectal tumors, nuclear and cytoplasmic beta-catenin was not increased in PJ polyps. These results point to an extensive redistribution of beta-catenin, which starts early in colorectal tumorigenesis. The nuclear accumulation in single cells of small adenomas can be considered as the first visible sign of the loss of APC function. Thus the immunohistochemical detection of beta-catenin distribution could serve as a criterion for estimating the malignant potential in the clinico-pathological evaluation of colon tumors during their early progression.

Adenoma↗
PubMed1999

[Automated quantitative image cytometry of bronchial washings in suspected lung cancer: comparison with cytology, histology and clinical diagnosis].

INTRODUCTION: Automated image cytometry represents a new method for the quantitative analysis of nuclear structure and DNA-content of exfoliative airway epithelial cells. In the present investigation, we examined the correlation between automated cytometry, conventional cytology and histopathology with the final diagnosis as the "gold standard". METHODS: In 142 patients (100 males and 42 females) with suspected lung cancer and 50 controls (COPD, asthma), bronchial washings (5-10 ml) were obtained during bronchoscopy before taking biopsies for cytological and/or histological examinations. The washings were collected in 20 ml Saccomanno's fixative and centrifuged (500 g, 15 min). The cell pellet was resuspended in Saccomanno's solution. Two specimens were stained according to Papanicolaou and another two using the Feulgen reaction with thionine. Image cytometry was performed by means of a special, trainable classifier for exfoliative cells of the respiratory tract, using the Cyto-Sacant (Oncometrics, Vancouver). RESULTS: In the patients with suspected lung cancer we found numerous abnormal nuclei in 97 samples, 36 samples contained normal cells only, and 9 samples were insufficient. In our control group there was no sample with abnormal nuclei, and all washings were evaluable. Compared to the final diagnosis of lung cancer, we found a sensitivity of 90% (92/102) and a specificity of 84% (26/31). For histology sensitivity was 91% (73/80) and specificity 100%, while we found a sensitivity of 92% (92/100) and specificity of 100% for cytology. For automated cytometry the positive predicted value was 95%, the negative predicted value 71%. CONCLUSIONS: In the investigation of patients with suspected lung cancer, automated image cytometry of bronchial washings is a sensitive and reliable method for the detection of malignant changes in the tracheobronchial mucosa. The automated procedure seems well suited not only for analysing bronchial washings, but also for a screening procedure.

Adult↗
PubMed1999

Soluble IL-6 receptor induces calcium flux and selectively modulates chemokine expression in human dermal fibroblasts.

Truncated forms of cytokine receptors have been regarded as modulators of the activity of their cognate ligands. In addition to inhibiting effects of their respective ligands, soluble receptors can also facilitate ligand-mediated signaling. Several studies have demonstrated that exogenous IL-6 in association with the soluble IL-6 receptor alpha (sIL-6Ralpha) can activate cells expressing the gp130 signal transducer lacking the specific, membrane-bound IL-6Ralpha. Since cell cultures of human dermal fibroblasts express high amounts of IL-6, we examined whether the addition of sIL-6Ralpha in association with endogenous IL-6 would be sufficient to stimulate these cells via gp130. As an early rapid signal we analyzed changes in intracellular free calcium concentrations ([Ca2+]i). Addition of sIL-6Ralpha induced an acute and transient increase in cytosolic free calcium concentrations in a dose-dependent fashion. This Ca2+-signal was abolished when cells were pretreated with anti-IL-6 or anti-gp130 antibodies. Using flow cytometric analysis we could demonstrate membrane-associated IL-6 and gp130, but not IL-6Ralpha on fibroblasts. We also analyzed MCP-1 and IL-8 expression as a response involved in the more recently recognized chemoattractant functions of fibroblasts, and found MCP-1 to be up-regulated, but not IL-8. These data suggest that sIL-6Ralpha binds to cell-associated, endogenous IL-6 produced by fibroblasts and this complex then activates the cells via gp130. This pathway of fibroblast activation by sIL-6Ralpha adds another dimension to the role of fibroblasts in the cytokine network.

Antigens, CD↗
PubMed1999

Budesonide for the treatment of collagenous colitis: first results of a pilot trial.

OBJECTIVE: Collagenous colitis is a chronic watery diarrhea disorder characterized by a subepithelial collagen layer and a lymphoplasmacytic infiltration within the lamina propria. However, no standard treatment has been introduced by controlled clinical trials. Aim of the present pilot trial was to investigate the clinical effects of orally administered budesonide (3 mg t.i.d.) in 7 patients with collagenous colitis. In addition, the histomorphological changes after budesonide treatment were described in a group of 3 patients. METHODS: The study was performed as an open label pilot trial. Study end point was the clinical remission of collagenous colitis defined by stool frequency and stool consistency. RESULTS: The results indicate a rapid and sustained clinical response in all patients. Stool frequency significantly decreased (p < 0.001) from 10.43 +/- 5.56 per day (4-20 per day) to 3.3 +/- 1.2 (1-5 per day) after 10 days and to 1.86 +/- 0.69 per day (1-3 per day) after 10 wk. Moreover stool consistency changed from watery (6 patients) or soft (1 patient) to soft (1 patient) or solid (6 patients). Clinical improvement was achieved within the first 10 days in all patients and maintained after dose reduction. In 3 patients no diarrhea recurred within 7, 12, or 15 months after treatment with budesonide was terminated. In these patients control biopsies were taken and showed a marked regression of both characteristics, the collagen band and the lymphoplasmacytic infiltration. CONCLUSIONS: With respect to the preliminary data from this pilot trial, budesonide with its high topical and low systemic effects seems to be of therapeutic clinical benefit in collagenous colitis. A therapeutic effect could be demonstrated for both therapeutic goals, the clinical response and morphological changes. Further studies on the effects of budesonide on mucosal collagen metabolism and long-term follow-up are warranted.

Anti-Inflammatory Agents↗
PubMed1999

Quinolines attenuate PAF-induced pulmonary pressor responses and edema formation.

In the present study we have investigated the mechanisms of pulmonary edema caused by platelet-activating factor (PAF) in isolated rat lungs as well as in mice in vivo. In blood-free perfused and ventilated rat lungs, PAF increased lung weight by 0.59 +/- 0.18 g. The cyclooxygenase inhibitor aspirin (500 microM) blocked this response by one-third, and the quinolines quinine (330 microM), quinidine (100 microM), and chloroquine (100 microM) by two-thirds. Lipoxygenase inhibition (10 microM AA861) alone or in combination with thromboxane receptor antagonism (10 microM SQ29548) had no effect on PAF-induced weight gain. In combination with aspirin, quinine or quinidine completely prevented PAF-induced weight gain and the concomitant increase of the capillary filtration coefficient (K(f,c)). Pretreatment with quinine in vivo prevented not only PAF-, but also endotoxin-induced edema formation as assessed by Evans Blue extravasation. In addition, in vivo quinine prevented the endotoxin-induced release of tumor neurosis factor (TNF). Furthermore, in perfused lungs quinine reduced the PAF-induced increases in airway and vascular resistance, as well as thromboxane release. These findings demonstrate the following anti-inflammatory properties of quinolines: reduction of thromboxane and TNF formation; reduction of PAF-induced vasoconstriction and bronchoconstriction; and attenuation of PAF- and lipopolysaccharide (LPS)-induced edema formation. We conclude that the PAF- induced edema consists of two separate mechanisms, one dependent on an unknown cyclooxygenase metabolite, the other one sensitive to quinolines.

Airway Resistance↗