E-cadherin regulates cell growth by modulating proliferation-dependent beta-catenin transcriptional activity.

beta-Catenin is essential for E-cadherin-mediated cell adhesion in epithelial cells, but it also forms nuclear complexes with high mobility group transcription factors. Using a mouse mammary epithelial cell system, we have shown previously that conversion of epithelial cells to a fibroblastoid phenotype (epithelial-mesenchymal transition) involves downregulation of E-cadherin and upregulation of beta-catenin transcriptional activity. Here, we demonstrate that transient expression of exogenous E-cadherin in both epithelial and fibroblastoid cells arrested cell growth or caused apoptosis, depending on the cellular E-cadherin levels. By expressing E-cadherin subdomains, we show that the growth-suppressive effect of E-cadherin required the presence of its cytoplasmic beta-catenin interaction domain and/or correlated strictly with the ability to negatively interfere with beta-catenin transcriptional activity. Furthermore, coexpression of beta-catenin or lymphoid enhancer binding factor-1 or T cell factor 3 with E-cadherin rescued beta-catenin transcriptional activity and counteracted E-cadherin-mediated cell cycle arrest. Stable expression of E-cadherin in fibroblastoid cells decreased beta-catenin activity and reduced cell growth. Since proliferating cells had a higher beta-catenin activity than G1 phase-arrested or contact-inhibited cells, we conclude that beta-catenin transcriptional activity is essential for cell proliferation and can be controlled by E-cadherin in a cell adhesion-independent manner.

Epithelial mesenchymal transition by c-Fos estrogen receptor activation involves nuclear translocation of beta-catenin and upregulation of beta-catenin/lymphoid enhancer binding factor-1 transcriptional activity.

Mouse mammary epithelial cells expressing a fusion protein of c-Fos and the estrogen receptor (FosER) formed highly polarized epithelial cell sheets in the absence of estradiol. Beta-catenin and p120(ctn) were exclusively located at the lateral plasma membrane in a tight complex with the adherens junction protein, E-cadherin. Upon activation of FosER by estradiol addition, cells lost epithelial polarity within two days, giving rise to a uniform distribution of junctional proteins along the entire plasma membrane. Most of the beta-catenin and p120(ctn) remained in a complex with E-cadherin at the membrane, but a minor fraction of uncomplexed cytoplasmic beta-catenin increased significantly. The epithelial-mesenchymal cell conversion induced by prolonged estradiol treatment was accompanied by a complete loss of E-cadherin expression, a 70% reduction in beta-catenin protein level, and a change in the expression pattern of p120(ctn) isoforms. In these mesenchymal cells, beta-catenin and p120(ctn) were localized in the cytoplasm and in defined intranuclear structures. Furthermore, beta-catenin colocalized with transcription factor LEF-1 in the nucleus, and coprecipitated with LEF-1-related proteins from cell extracts. Accordingly, beta-catenin- dependent reporter activity was upregulated in mesenchymal cells and could be reduced by transient expression of exogenous E-cadherin. Thus, epithelial mesenchymal conversion in FosER cells may involve beta-catenin signaling.

[Effects of injury pattern on the predictability of 4 multiple trauma scores. Presentation of a method for identifying artifacts]. / Einfluss des Verletzungsmusters auf die Vorhersagekraft von vier Polytraumascores. Darlegung einer Methode zur Suche nach Störfaktoren.

When comparing two populations of multiply injured patients differences in patient characteristics must be controlled for. To measure the overall severity of injury, scaling systems are used. If after adjustment for injury severity, the proportion of deaths in the two data sets are still different, the difference is to be considered as due to the quality of care. However, this conclusion is only valid after excluding the possibility that the scale in use fails to adequately reflect certain injuries. The scope of the study is to demonstrate a method for examining this potential interference. As an example, four widely used scales were applied to the data of 418 multiply injured patients. By means of multiple logistic regression analysis, variables were selected which have an influence on prognosis in addition to a scale, thus indicating a subgroup of patients who are underrepresented by the respective scoring system. For the scales examined, these additional variables were: Head and thoracic trauma for the Polytrauma score (Oestern), abdominal and thoracic trauma for the Trauma index (Schreinlechner), thoracic trauma and age for the Trauma score (Champion), head trauma and age for the Injury Severity Score (Baker). We conclude that each score analyzed had its characteristic weak points. Prognostic quality was affected by casemix. Therefore, comparisons between groups of polytraumatized patients may be invalidated. The method outlined here is a useful means for checking a scoring system for these types of interfering variables. Therefore, it is recommended to search routinely for potentially interfering variables before applying a scale. In a given data set of multiply injured patients, appropriate adjustments can then be made for the deficiencies of the scoring system.

Detergent-salt resistance of LAP2alpha in interphase nuclei and phosphorylation-dependent association with chromosomes early in nuclear assembly implies functions in nuclear structure dynamics.

Lamina-associated polypeptide (LAP) 2 of the inner nuclear membrane (now LAP2beta) and LAP2alpha are related proteins produced by alternative splicing, and contain a common 187 amino acid N-terminal domain. We show here that, unlike LAP2beta, LAP2alpha behaved like a nuclear non-membrane protein in subcellular fractionation studies and was localized throughout the nuclear interior in interphase cells. It co-fractionated with LAP2beta in nuclear lamina/matrix-enriched fractions upon extraction of nuclei with detergent, salt and nucleases. During metaphase LAP2alpha dissociated from chromosomes and became concentrated around the spindle poles. Furthermore, LAP2alpha was mitotically phosphorylated, and phosphorylation correlated with increased LAP2alpha solubility upon extraction of cells in physiological buffers. LAP2alpha relocated to distinct sites around chromosomes at early stages of nuclear reassembly and intermediarily co-localized with peripheral lamin B and intranuclear lamin A structures at telophase. During in vitro nuclear assembly LAP2alpha was dephosphorylated and assembled into insoluble chromatin-associated structures, and recombinant LAP2alpha was found to interact with chromosomes in vitro. Some LAP2alpha may also associate with membranes prior to chromatin attachment. Altogether the data suggest a role of LAP2alpha in post-mitotic nuclear assembly and in the dynamic structural organization of the nucleus.

Polarisation-dependent association of plectin with desmoplakin and the lateral submembrane skeleton in MDCK cells.

The intermediate filament-binding protein plectin and cytokeratin were localised at the cellular periphery of fully polarised Madin-Darby canine kidney (MDCK) cells, whereas vimentin was primarily found in a perinuclear network. Confocal and immunoelectron microscopy revealed that plectin was restricted to areas underlying the lateral plasma membrane. It colocalised with fodrin, a component of the submembrane skeleton, and was closely associated with desmosomal plaque structures. Biochemically, plectin was shown to interact directly with immunoprecipitated desmoplakin in vitro. Upon loss of cell polarity in low calcium medium, plectin redistributed to a cytoplasmic vimentin- and cytokeratin-related network, clearly distinct from diffusely distributed fodrin and internalised desmoplakin structures. The structural reorganisation of plectin was also reflected by an increased solubility of the protein in Triton X-100/high salt, and a decrease in its half-life from approximately 20 to approximately 5 hours. Furthermore, unlike cytokeratins and vimentin, desmoplakin and fodrin did not associate with plectin attached to magnetic beads in cell lysates of unpolarised cells, while all proteins formed a stable complex in polarised cells. Altogether, these data indicate that plectin is involved in the anchorage of intermediate filaments to desmosomes and to the submembrane skeleton in polarised MDCK cells.

[Computer-assisted evaluation of bicycle ergometry for determining level of endurance training in physical fitness]. / Computerunterstützte Auswertung der Fahrradergometrie zur Dosierung des Ausdauertrainings im Gesundheitssport.

Recent studies have provided evidence of the importance of aerobic endurance training as an independent factor with regard to reducing morbidity and mortality from cardiovascular diseases. Clinical routine shows that test methods and training recommendations are often not specific enough for efficient, yet safe exercise. Software is presented which allows cycle ergometry to be used according to standard criteria in clinical practice, with special attention to the requirements for training with health benefit. Technical requirements: 1. Cycle ergometer with the possibility of increasing exercise intensity by Watt (W) increments; 2. ECG or other device for accurate pulse monitoring; 3. IBM-compatible PC and printer. Based upon the input of data on birth date, sex, height, weight, and heart rate (HR) at rest the programme calculates body surface area, the reference value of physical work capacity of matching subjects and the expected maximal HR (HRmax,exp) and HRmax,exp x 0.95. After the test, input of HR at exhaustion (HRmax), maximum achieved W-increment and time cycled at this intensity in seconds provides various parameters of the individual work capacity. The maximal work performance W (Wmax) is calculated. This value is used to provide further calculations of Wmax.kg-1, VO2max.kg-1 and the maximal work performance as a percentage of the normal value (LF%). The software provides an individual training plan with incremental extension of training time and a prescription for heart rate controlled intensity of endurance training based upon medically accepted training principles. The software enables a standard test to be used and recommends medically efficient and secure quality and quantity guidelines for endurance training.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prognosis of epidural hematoma: is emergency burr hole trepanation in craniocerebral trauma still justified today?]. / Prognose nach epiduralem Hämatom: ist die notfallmässige Bohrlochtrepanation beim Schädel-Hirn-Trauma heute noch zeitgemäss?

We made a retrospective study of the records of 80 patients with epidural haematoma, to investigate whether delay between injury and surgery and neurological status upon admission affect outcome after 3-6 months. Outcome was classified on a four-grade scale, grade 1 meaning full recovery and grade 4, death. Overall mortality was 13%. Patients operated on within 7 h after injury made a full recovery in 52%, and mortality in this group was 6%. Patients operated on between 7 h and 14 h after injury made a full recovery in 20%; mortality was 16%. Among the patients who were not comatose on admission a good outcome was achieved in 55% and mortality was 3%. The outcome in patients who were comatose on admission was rated grade 1 in 15% and grade 4 in 25%. The proportion of comatose patients and the mortality were higher in patients transferred from general hospitals. Textbook signs of epidural haematoma are not reliable aids to diagnosis and localization; for example a lucid interval occurred in only 58% of our patients. It is concluded that emergency burr hole trepanation might improve the outcome in patients showing signs of brain stem dysfunction after head injury, but prior computed tomography is necessary to guide such an intervention at the district hospital level.