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In eukaryontischen Zellen werden Zytoplasma und Nukleoplasma durch die Kernhülle voneinander getrennt. Große Moleküle können diese Barriere, die aus zwei Membranen besteht, nur durch sogenannte Kernporen passieren. Kernporen sind gigantische Proteinkomplexe, die neben der passiven Diffusion von Ionen den aktiven Transport von Makromolekülen vermitteln. In mehrzelligen Organismen bricht die Kernhülle mitsamt den darin eingebetteten Kernporenkomplexen während der Mitose zusammen, damit die Chromosomen auf die Tochterzellen aufgeteilt werden können. Am Ende der Mitose werden die Kernporen durch Rekrutierung einzelner Bausteine, der Nukleoporine, wieder am Chromatin aufgebaut. Wie diese Bausteine miteinander interagieren, welches Nukleoporin durch ein anderes rekrutiert wird und welche Nukleoporine direkt an das Chromatin binden, ist ein zurzeit intensiv untersuchtes Forschungsgebiet. Die AG-Antonin hatte herausgefunden, dass das an der nukleoplasmatischen Seite der Kernporenkomplexe lokalisierte Nukleoporin Nup50 essentiell für den Wiederaufbau von Kernporenaufbau am Ende der Mitose ist. Über Nup50 wusste man bisher nur, dass es beim Import von Proteinen in den Zellkern beteiligt ist, aber über diese zusätzliche Funktion waren keine Details bekannt. In dieser Arbeit habe ich gezeigt, dass ein Nup50-Fragment von 48 Aminosäuren dafür verantwortlich ist, dass dieses Protein an Kernporen lokalisiert. Innerhalb dieses entscheidenden minimalen Bindungsfragments wurden drei Aminosäuren identifiziert, deren Mutationen die Lokalisation von Nup50 an der Kernhülle aufheben und die damit notwendig für die Kernporenlokalisation sind. Durch GST-Pulldown-Versuche mit zellulären Extrakten konnte nachgewiesen werden, dass die drei genannten Mutanten die Bindung zwischen rekombinanten Nup50 und zwei weiteren Nukleoporinen, Mel-28 und Nup153, verhindern. Darüber hinaus stelle ich vor, wie in HeLa-Zellen die Lokalisation von Nup50 an Chromatin während des Austritts aus der Mitose analysiert werden kann. Ich konnte zeigen, dass jene drei Mutanten die Chromatinlokalisation nicht inhibieren. Diese Ergebnisse deuten darauf hin, dass die Interaktion von Nup50 mit dem Chromatin am Ende der Mitose nicht durch Bindung an Mel-28 oder Nup153 stattfindet.

Bei der Teilung einer Zelle werden das Genom und die Zellbestandteile zwischen zwei Tochterzellen aufgeteilt. Dies erfordert verschiedene fein aufeinander abgestimmte Vorgänge. Unter anderem ist eine proteinreiche Struktur beteiligt, die 1891 entdeckt wurde: der Mittelkörper. In vorliegender Arbeit wurden gezielt gekennzeichnete Mittelkörperproteine analysiert und verschiedene Phasen des Transports unterschieden. Es erfolgten erstmals Messungen unter Nutzung der ZF1-Methode. Zudem wird anhand der ZF1-Technik nachgewiesen, dass im Rahmen der Zellteilung die Trennung der interzellulären Brücke zu beiden Seiten des Mittelkörpers stattfindet, woraufhin dieser nach extrazellulär abgegeben wird und über einen der Phagozytose ähnlichen und von Aktin abhängigen Mechanismus von einer Tochterzelle oder unverwandten Nachbarzelle aufgenommen wird., In animals, the midbody coordinates the end of cytokinesis. Using the ZF1-mediated degradation technique it is shown that midbodies are released outside the cell in C. elegans embryos. Furthermore it is shown that midbodies are released after abscission cuts on both sides of the midbody and that released midbodies are internalized via actin-driven phagocytosis.

Gastrointestinale Stromatumoren (GIST) sind die häufigsten mesenchymalen Neoplasien des Gastrointestinaltraktes. Bis heute gibt es keine international verbindliche Risikoklassifikation und so existieren zahlreiche Einteilungssysteme. Häufig wird die Dignität des Primärtumors anhand der Tumorgröße, der Mitoserate und der Tumorlokalisation bestimmt. Die Mitoserate wird bei den meisten Klassifikationssystemen in 50 HPF (high power fields) ausgezählt. Die Grundfläche von 1 HPF ist aufgrund der Verwendung neuerer Mikroskope mit Weitwinkelobjektiven und durch die Klassifikationen selbst nicht einheitlich definiert und so variiert die Grundfläche von 50 HPF von 5,0 bis hin zu 11,9 mm². Ziel dieser Studie war es, die fünf gegenwärtig diskutierten Risikoklassifikationssysteme für Gastrointestinale Stromatumoren von Fletcher et al., Miettinen et al., Huang et al., Joensuu und der TNM-Klassifikation (Tumorgröße, Lymphknoten und Metastasenstatus) hinsichtlich ihres prädiktiven Wertes anhand eines eigenen, unabhängigen GIST-Kollektivs unter standardisierter Bestimmung der Mitoserate zu reevaluieren. Die Daten von 558 eingewilligten GIST- Patienten wurden retrospektiv analysiert und klinisch prospektiv nachbeobachtet. Es wurden ausschließlich GIST im Magen oder Dünndarm, R0-Resektionen, initial nicht metastasierte Neoplasien und Tumorverläufe ohne den Einfluss von Tyrosinkinaseinhibitoren in die Studie aufgenommen. Die Mitoserate wurde standardisiert ermittelt. Alle fünf betrachteten Einteilungssysteme konnten bei den Survivalanalysen bezüglich des krankheitsspezifischen und krankheitsfreien Überlebens Patienten mit high-risk von denen mit non-high-risk signifikant unterscheiden, jedoch war keine Klassifikation den anderen überlegen. Im Overall-Survival zeigte sich keine signifikante Differenz. Inhomogene Tumorverläufe fanden sich vor allem innerhalb der high-risk Gruppe. Zusammenfassend lässt sich feststellen, dass durch die Standardisierung der Mitoserate eine realistische Gegenüberstellung von fünf Risikoklassifikationssystemen gelungen ist. Alle Klassifikationssysteme zeigten eine signifikante Differenzierung zwischen high-risk und non-high-risk GIST. Zudem konnte dargestellt werden, dass eine Vielzahl anderer, nicht GIST-bedingter Faktoren zum Tod führen und die Differenzierung von Overall-Survival, krankheitsspezifischem und krankheitsfreiem Überleben für eine qualifizierte Beurteilung des Überlebens von GIST-Patienten unverzichtbar ist. Weiterhin wiesen alle Klassifikationssysteme eine verbesserte, aber immer noch limitierte Trennschärfe innerhalb der Gruppe der high-risk GIST auf. Die durch eine falsch erhöhte Mitoserate resultierenden Konsequenzen mit Risikoüberschätzung, der daraus folgenden Therapie mit Tyrosinkinaseinhibitoren, sowie deren unerwünschten Nebenwirkungen, zusätzlichen Behandlungskosten und Resistenzentwicklung gilt es in Zukunft zu minimieren.

Neuroendocrine Neoplasms are classified according to the new WHO classification in (1.) well differentiated neuroendocrine tumors G1 (NET G1, Ki67 ≤ 2 or mitosis count2) and (2.) well differentiated neuroendocrine tumors G2 (NET G2, Ki67 3-20 or mitosis count 2-20) and (3.) poorly differentiated neuroendocrine carcinomas G3 (NEC G3, Ki67 20 or mitosis count20).In this study 310 NENs of the Ludwig-Maximilians-University in Munich were reevaluated according to the new WHO classification.7% of the analyzed NENs were presented as neoplasias of the stomach. In NENs of the stomach three distinct subtypes are recognized: (1) type 1 associated with autoimmune chronic atrophic gastritis (2) type 2, associated with multiple endocrine neoplasia (MEN1) and Zollinger-Ellison Syndrom; and (3) type 3, sporadic tumors.Precursor lesions (i. e. hyperplasia of the ECL cells) are found in patients with hypergastrinaemia (type 1 and 2). This article should provide insights into the diagnosis of NENs of the stomach with emphasis on the new international standard.

Conventionally, neuronal development is regarded to follow a stereotypic sequence of neurogenesis, migration, and differentiation. We demonstrate that this notion is not a general principle of neuronal development by documenting the timing of mitosis in relation to multiple differentiation events for bipolar cells (BCs) in the zebrafish retina using in vivo imaging. We found that BC progenitors undergo terminal neurogenic divisions while in markedly disparate stages of neuronal differentiation. Remarkably, the differentiation state of individual BC progenitors at mitosis is not arbitrary but matches the differentiation state of post‐mitotic BCs in their surround. By experimentally shifting the relative timing of progenitor division and differentiation, we provide evidence that neurogenesis and differentiation can occur independently of each other. We propose that the uncoupling of neurogenesis and differentiation could provide neurogenic programs with flexibility, while allowing for synchronous neuronal development within a continuously expanding cell pool.

We asked whether cell-cycle associated protein p27kip1 might be involved in the transition of precursor cells to postmitotic maturation in adult hippocampal neurogenesis. p27kip1 was expressed throughout the dentate gyrus with a strong nuclear expression in early postmitotic, calretinin-positive neurons and neuronally determined progenitor cells (type-3 and some type-2b), lower or absent expression in radial glia-like precursor cells (type-1) and type-2a cells and essentially no expression in granule cells. This suggested a transitory role in late proliferative and early postmitotic phases of neurogenesis. Inconsistent with a role limited to cell cycle arrest the acute stimuli, voluntary wheel running (RUN), environmental enrichment (ENR) and kainate-induced seizures increased p27kip1 expressing cells. Sequential short-term combination of RUN and ENR yielded more p27kip1 cells than either stimulus alone, indicating an additive effect. In vitro, p27kip1 was lowly expressed by proliferating precursor cells but increased upon differentiation. In p27kip1−/− mice neurogenesis was reduced in vivo, whereas the number of proliferating cells was increased. Accordingly, the microdissected dentate gyrus of p27kip1−/− mice generated more colonies in the neurosphere assay and an increased number of larger spheres with the differentiation potential unchanged. In p27kip1−/− monolayer cultures, proliferation was increased and cell cycle genes were upregulated. In the Morris water maze p27kip1−/− mice learned the task but were specifically impaired in the reversal phase explainable by the decrease in adult neurogenesis. We conclude that p27kip1 is involved in the decisive step around cell-cycle exit and plays an important role in activity-regulated and functionally relevant adult hippocampal neurogenesis.

Since early February 2010 we have been implementing the latest version of the 2009 AJCC Melanoma Staging and Classification in our institution. Since, according to the guidelines for stage pT1 melanomas, the number of mitoses/mm(2) is of particular significance, we have been able to observe a notable shift from pT1a to pT1b. Highlighting the mitotic count as one of the key features of the diagnosis of malignant melanoma, we observed that the major part of stage-switched melanomas belonged to a minimally invasive subset of melanomas previously categorized as pT1a UICC (7(th) edition). A level of reasonable doubt remains regarding the distinct histogenetic classification of mitosis as early stage melanoma with regard to their epithelial or melanocytic origin.

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The diagnosis and therapy of neuroendocrine tumors (NETs) of the stomach are based on their exact classification and risk stratification. Since the incidence of gastric NETs has risen sharply over the last 35 years and most tumors are detected endoscopically at an early stage, they have come to represent a challenge for the pathologist. Gastric NETs are classified according to the WHO and TNM classifications and additionally separated into four biologically distinct types: Well differentiated type 1 and 2 gastric NETs (G1) smaller than 2 cm, and type 3 smaller than 1 cm that do not infiltrate the muscularis propria or show angioinvasion have a good prognosis and can be removed endoscopically. Well differentiated type 1 and 2 gastric NETs (G1-G2) larger than 2 cm or type 3 with a diameter above 1 cm or with infiltration of the muscular wall and/or angioinvasion and poorly differentiated (type 4) neuroendocrine carcinomas carry a poor prognosis and need to be treated aggressively. Endosonography is the method of choice for determining the size, depth of infiltration and presence of lymph node metastases. With exact diagnosis and adequate treatment, the majority of patients with gastric NETs have a favorable prognosis.

Im Rahmen der vorliegenden Arbeit sollte die Funktion von GAS41 in der Zellteilung untersucht werden. Hierzu wurde ein RNAi vermittelter Knockdown in den Zelllinie HeLa und TX3868 etabliert. An GAS41 depletierten Zellen konnte mit Hilfe von Microarray Analysen gezeigt werden, dass GAS41 einen Einfluss auf die Zellteilung ausübt. Auf zellulärer Ebene konnte GAS41 als centrosomales Protein charakterisiert werden. In mitotischen Zellen kommt es durch die Deregulation der GAS41 Expression zur Ausbildung multipolarer Spindelapparate sowie zu einer Störung der Chromosomenanordnung in der Äquatorialebene. Die Ausbildung multipolarer Spindeln führt dabei nicht zu einem Mitoseabort sondern erfolgt unter der Entstehung mehrerer Tochterzellen. Darüber hinaus konnte in GAS41 depletierten Zellen mit multipolarem Spindelapparat beobachtet werden, dass in diesen Zellen während der Metaphase ein Centrosomenclustering zur Wiederherstellung einer bipolaren Orientierung erfolgen kann. Auch die fehlerhaft angeordneten Chromosomen können nacheinander mit Mikrotubuli verknüpft und in der Metaphaseplatte angeordnet werden. Diese komplexen Umlagerungen sind mit einer verzögerten Zellteilung verknüpft. GAS41 ist essentiell für die Ausbildung einer bipolaren Spindel. Eine Expressionsänderung induziert die Ausbildung multipolarer, aber funktioneller Spindelapparate und führt zu einer erhöhten chromosomalen Instabilität. The aim of the presented work was, to characterize the physiological function of GAS41 during cell division. Therefore, a RNAi-mediated knockdown was established in HeLa and TX3868 cells. Microarray analysis of GAS41 depleted cells confirmed the postulated influence of GAS41 on mitosis. GAS41 was identified as protein with centrosomal localization. In mitotic cells the deregulation of GAS41 caused metaphases with multipolar spindles and unaligned chromosomes. The development of multipolar spindles did not compromise the successful exit from mitosis. Cell division occurred under formation of multiple daughter cells. Additionally, GAS41 depleted cells were able to rescue their bipolar phenotype via centrosome clustering during metaphase. Even unaligned chromosomes were attached to microtubules and aligned to the equatorial plane. Both mechanisms to rescue the proper bipolar phenotype were connected to a mitotic delay. GAS41 is an essential protein for the establishment of a bipolar mitotic spindle. The deregulation of GAS41 expression induces the formation of multipolar, but functional mitotic spindles and promotes chromosomal instability.

Leiomyomas are by far the most frequent mesenchymal uterine neoplasms. Leiomyoma variants refer to a particular histological differentiation and growth pattern, respectively. To assess malignancy, an algorithm is used based on the presence or absence of cellular atypia, tumor cell necrosis and mitosis. In addition, vascular invasion is a criterion for malignancy. Ischemic or infarct type necrosis is not considered a criterion for malignancy. The differential diagnosis of leiomyosarcoma includes cellular and mitotically active leiomyoma and leiomyoma with extensive infarct type necrosis (apoplectic leiomyoma). The term smooth muscle tumor of uncertain malignant potential (STUMP) should be reserved for tumors with uncertainty regarding cell type, type of necrosis and mitotic index, as well as for special cases of myxoid and epithelioid smooth muscle neoplasms. Immunohistochemically, the expression of desmin and caldesmon is indicative of smooth muscle tumors, while stromal tumors can express smooth muscle actin and, rarely, desmin in addition to CD10.

Das humane LIN-9 wurde zuerst als pRB-interagierendes Protein beschrieben und spielt eine Rolle als Tumorsuppressor im Kontext des pRB-Signalweges. Die Homologe von LIN-9 in D. melanogaster und in C. elegans, sind an der transkriptionellen Regulation verschiedener Genen beteiligt. B-MYB ist als direktes E2F-Zielgen in D. melanogaster als Transkriptionsfaktor an der Genregulation differenzierungsspezifischer und zellzyklusregulierender Gene beteiligt und auch in Vertebraten (Zebrafisch) konnte ihm die Rolle eines haploinsuffizienten Tumorsuppressors zugewiesen werden. Der Verlust von B-MYB führte jeweils zu einem Anstieg von aneu- und polyploiden Zellen. Dies und die Tatsache, dass sowohl LIN-9 als auch B-MYB in der Genregulation von G2/M-Zielgenen eine Rolle spielen, ließ bedeutende Funktionen dieser Proteine in der Zellzyklusregulation vermuten. Primäres Ziel dieser Arbeit war daher die molekularbiologische Funktion von LIN-9 und B-MYB, besonders im Hinblick auf ihre Bedeutung während der Mitose, zu untersuchen. Dazu sollte mit Hilfe von FACS-Analysen, das Zellzyklusprofil LIN-9 oder B-MYB depletierter primärer humaner Neuroblastomzellen (SHEP-Zellen) im Vergleich zu Kontrollzellen untersucht werden. Hierfür wurden zunächst weitere shRNAs getestet, um die posttranskriptionelle Expression von LIN-9 in BJ-ET Zellen effizient zu reprimieren. In dieser Arbeit konnten zunächst Ergebnisse reproduziert werden, die zeigten, dass der Verlust von LIN-9 und B-MYB zu einer verminderten Expression einer Gruppe G2/M-spezifischer Gene führt, deren Produkte für die Funktion des Mitose-Checkpoints benötigt werden. Die verminderte Expression von G2/M-Genen in LIN-9 bzw. B-MYB depletierten Zellen geht mit einer Reihe phänotypischer Veränderungen einher, wie einen Defekt im mitotischen Spindel-Checkpoint, der dazu führt, dass die Zellen die Mitose auch nach Behandlung mit einem Spindelgift vorzeitig verlassen. Bei zusätzlichem Trigger kommt es in LIN-9 und B-MYB depletierten Zellen, bei weiterhin geringer ausgeprägtem G2/M-Block, zu einer deutlich erhöhten Apoptoserate, ohne signifikanten Anstieg von Aneu- oder Polyploidie. Eine Abhängigkeit von p53 oder p21 konnte nicht nachgewiesen werden. Bei Hinweisen auf eine deutlich verlangsamte Proliferation und einer Akkumulation der Zellen in der G2/M-Phase, ergaben die mit Hilfe eines Durchflusszytometers erstellten Zellzykluskinetiken, dass die Progression LIN-9 bzw. B-MYB depletierter Neuroblastomzellen von der S-Phase durch die G2/M-Phase und in die nächste G1-Phase deutlich verzögert ist. Es konnte weder ein Arrest dieser Zellen in der Mitose noch eine veränderte Länge der S-Phase nach LIN-9 oder B-MYB Depletion festgestellt werden. Daher ist die verlangsamte Zellzyklusprogression nach LIN-9 bzw. B-MYB Verlust höchstwahrscheinlich auf einen Defekt in der späten G2-Phase zurückzuführen, welcher in einem verzögerten Eintritt in die Mitose resultiert. In D. melanogaster und in C. elegans sind die Homologe von LIN-9 und B-MYB zusammen, als Bestandteile hoch konservierter RB/E2F-Komplexe, an der Regulation von Genen entscheidend beteiligt. Daher liegt es nahe, dass im humanen System LIN-9 und B-MYB ebenfalls Bestandteile eines ähnlichen Komplexes sind und dadurch in die Zellzyklusregulation eingreifen. Schlüsselwörter: LIN-9; B-MYB; Zellzyklus; G2/M-Übergang; Mitose, The human LIN-9 Protein was first identified as a novel pRB-interacting Protein which acts as a tumorsuppressor in context of the pRB-pathway. The homologs of LIN-9 in D. melanogaster and C. elegans are required for the transcriptional regulation of different genes. B-MYB is a direct target-gene of E2F in D. melanogaster and acts as a transcriptionfactor and participates in the activation of differentiation specific and cellcycle regulating genes. Also, in vertebrates (zebra fish) B-MYB was described as a haploinsufficient Tumorsuppressor and depletion of B-MYB leads to increased numbers of an- and polyploid cells. This and the fact, that both LIN-9 and B-MYB cooperate with pRB in the activation of differentiation specific genes let to the hypothesis, that these genes could play an important role in the transcriptional regulation of genes. Thus, the primary goal of this thesis was to identify the function of LIN-9 and B-MYB, specifically during mitosis. For that purpose, the progression through the cell cycle of LIN-9 or B-MYB depleted SHEP-cells in comparison to control cells should be analyzed (FACS). Therefore an RNAi-based system was established, that efficiently represses the posttranscriptional expression of LIN-9 and B-MYB in SHEP cells. It was possible to reproduce results which showed that the loss of LIN-9 or B-MYB lead to a reduced expression of a cluster of G2/M-specific genes, whose products are required for the mitotic checkpoint. The reduced expression of these genes is accompanied by phenotypically changes, such as a defect of the mitotic spindle checkpoint, which leads to an early termination of mitosis after nocodazole treatment. With an additional trigger LIN-9 and B-MYB depleted cells show a high rate of apoptotic cells, while the G2/M-Block is less characteristic but still existent. There was no significant increase of an- or polyploidy and no dependency on p53 or p21. Cell cycle kinetics generated by flowcytometry revealed that the progression of LIN-9 or B-MYB depleted cells from S-phase to G2/M-phase and into the next G1-Phase is significantly delayed. In summary, depletion of LIN-9 or B-MYB results neither in an arrest in mitosis nor in a significantly changed S-phase length of these cells. This indicates that the slowed progression through the cell cycle is most likely due to a defect in the late G2-phase, which results in a delayed entry into mitosis. The homologes of LIN-9 and B-MYB in D. melanogaster and C. elegans act together as subunits of highly conserved RB/E2F-complexes in the regulation of genes, which suggests, that LIN-9 and B-MYB are also components of a similar complex in humans and thereby mediate the regulation of the cell cycle. Keywords: LIN-9; B-MYB; cell cycle; G2/M-transition; mitosis; transcription

The prognosis of the generally benign meningiomas is mainly an issue of the likelihood of recurrence, which increases with WHO grade (7-20% in WHO grade I, 29-40% in WHO grade II, and 50-78% in WHO grade III meningiomas). Among clinical parameters the most important prognostic factor is the completeness of neurosurgical tumor resection. Among histopathological prognostic parameters the mitotic activity is the most important one. As the cutoffs of the mitotic index (MI) are defined for each grade by the WHO classification of brain tumors and because the MI can be applied as the sole grading criterion, the reliable and reproducible assessment of the MI is crucial for an appropriate risk stratification. This is provided by immunohistochemical mitosis markers, i.e., phospho-histone H3 (PHH3). The PHH3 method is superior to the conventional mitosis counting method and therefore allows a more reliable risk stratification. The Ki-67 labeling index provides additional prognostic information, especially in prognostically ambiguous meningiomas. Cytogenetically, the deletion of the short arm of one chromosome 1 (1p-) is an unfavorable prognostic parameter and is correlated with a high risk of recurrence. The enzyme reaction for alkaline phosphatase (ALPL) is a fast and efficient screening method, which strongly indicates an intact chromosome 1 in cases with a positive enzyme reaction.

Lymphomatoid papulosis is a rare disease with a worldwide incidence of 1.2 to 1.9 per 1 million. It affects all age groups with a peak incidence between 30 and 40 years and an apparent male predominance. Occurrence in childhood has also been described. Both the etiology and pathogenesis of the disease are unknown. The clinical presentation is extremely variable and frequently uncharacteristic. A papulonodular eruption, characterized by self-healing skin lesions appearing in crops can often be seen, particularly on extremities. We report on 17 patients, including 2 children. By detailing 6 cases we point out the variable morphologic manifestations, the different courses of disease and therapeutic options.

1\. Titelblatt und Inhaltsverzeichnis 2\. Einleitung 3\. Material und Methoden 4\. Ergebnisse 5\. Diskussion und Ausblick 6\. Zusammenfassung & Summary 7\. Literaturverzeichnis 8\. Anhang 9\. Danksagung, In dieser Arbeit wird erstmalig eine noch unbekannte zellzyklusabhängige Phosphorylierung des zytostatischen CDK-Inhibitors p21 vorgestellt. p21 wird hierbei zu Beginn der Mitose im Zellkern am Thr-145 phosphoryliert. Es konzentriert sich im weiteren Verlauf der Mitose in spezifischen Kompartimenten der sich teilenden Zelle. Nach anfänglicher, diffuser Verteilung innerhalb des Zellkerns (Prophase) ist es im weiteren Prozess der Mitose ausschließlich an den Spindelpolen (Prometa- und Metaphase), später jedoch nur noch an der Teilungsfurche (Telophase) und im Bereich des kontraktilen Ringes (Zytokinese) zu detektieren. In eukaryotischen Zellen während der Interphase ist p21 nicht phosphoryliert. Die spezifische, zeitabhängige Lokalisation an den Spindelpolen und später im Bereich des kontraktilen Rings lassen auf verschiedene Funktionen schließen, die p-p21-Thr145 im Prozess der Mitose erfüllt. Bisherige Arbeiten beschreiben die induzierte Phosphorylierung von p21 am Thr-145 nach Substanzbehandlung oder Proteintransfektion in der G1-, S- und G2-Phase des Zellzyklus. Hierbei konnte eine proliferative und anti-apoptotische Wirkung nachgewiesen werden. Aufgrund der vorliegenden Daten muss also zwischen der zellzyklusabhängigen Phosphorylierung von p21 in der Mitose und der induzierten Phosphorylierung während der Interphase unterschieden werden. Die induzierte Phosphorylierung kann durch Fehlregulationen von Kinasen verursacht werden, deren Überexpression in verschiedenen Tumorarten festgestellt wurde. Zu diesen Kinasen gehört Pim-1. Um die Interaktion zwischen Pim-1 und p21 in lebenden Zellen zu untersuchen, wurden beide mit autofluoreszierenden Proteinen markiert. Zunächst wurden die p21- und Pim-1-spezifischen Funktionen der Fusionsproteine in biochemischen und zellbasierten Experimenten überprüft. In anschließenden Transfektionsstudien konnte die Phosphorylierung von endogenem p21 durch Pim-1-WT-GFP im Zellkern eukaryotischer Zellen festgestellt werden. Die Phosphorylierung von endogenem p21 durch Pim-1-WT-GFP führte zudem zu einer Translokation von p-p21-Thr145 in das Zytosol. Hier kann es an den Mitochondrien mit Procaspase-3 interagieren und so den Fas-vermittelten Apoptoseweg inhibieren. Die induzierte, unkontrollierte Phosphorylierung des zytostatischen Zellzyklusinhibitors p21 durch erhöhte Pim-1-Enzymaktivität, kann so eine proliferative und anti-apoptotische Wirkung auf die Zelle haben und deren unkontrolliertes Wachstum fördern. Zusätzlich wird in der vorliegenden Studie ein neu entwickelter funktioneller HCA-Assay vorgestellt, mit dem anhand der Thr-145-Phosphorylierung von endogenem p21 durch Pim-1-WT- GFP potentielle Pim-1-Inhibitoren in lebenden Zellen analysiert werden können. Die Phosphorylierung von p21 wurde hierbei als Maß der Pim-1-WT-GFP- Enzymaktivität und reziprok für die Wirksamkeit eines potentiellen Inhibitors unter zellulären Bedingungen verwendet., The protein p21 is involved in several regulating processes during the G1, S and G2 phase of the cell cycle. In the present study, we demonstrated that p21 is also involved in the process of mitosis. At the onset of mitosis, p21 is phosphorylated at Thr-145 and accumulates at the spindle poles where it remains until chromosomes segregation occurs. At the beginning of cytokinesis, phosphorylated p21 shuttles from the centrosomes to the cleavage furrow and seems to be associated with the contractile ring until the end of mitosis. The localization of p-p21-Thr145 within specific compartments during mitosis transition implies its participation in functional processes where at first the centrosomes and later the contractile ring are involved in. Previous publications described an induced phosphorylation of p21 at Thr145 after cell treatment during the interphase of the cell cycle. This phosphorylation inhibited the cytostatic properties of p21 in these cells and caused proliferative and anti-apoptotic effects. For that reason, it is important to distinguish between the cell cycle dependent phosphorylation of p21 during mitosis progression and the induced phosphorylation during the interphase of the cell cycle. The induced phosphorylation can be a result of dysregulated kinases which are upregulated in several types of cancer. Pim-1 is one of these tumor related kinases. Pim-1 and p21 were attached to autofluorescent proteins to study their interactions in living cells. The proper functions of the fusion proteins were proved in biochemical and cell based assays. This study demonstrates that increased expression of Pim-1-WT-GFP leads to the phosphorylation of endogenous p21 within the nucleus. Additionally, p-p21-Thr145 was also detected within the cytosol in a subpopulation of these cells. Here it can interact with procaspase-3 or ASK1, preventing the induction of apoptosis. The induced phosphorylation as a result of increased Pim-1 enzyme activity can lead to proliferative and anti apoptotic effects, both of which can actively contribute to tumorigenesis. Furthermore, the Pim-1 -WT-GFP dependent phosphorylation of endogenous p21 was used to analyse the effect of potential Pim-1 inhibitors under cellular conditions in a new functional HCA assay. The intracellular phosphorylation of p21 was used as a read out parameter for the Pim-1 enzyme activity and for the effect of the potential Pim-1 inhibitors, respectively.

Granular cell tumors are, in almost all cases, benign soft tissue tumors, although malignant variants have rarely been described in a variety of anatomical locations. In the case presented here, a so-called atypical granular cell tumor was diagnosed based on two criteria, being differentiated from the usual histological findings by enhanced mitotic activity and focal spindle cell proliferation. Further suspicious characters of the tumor were its size of 13x10x5 cm on MRT as well as its long-term clinical course (1.5 years). The diagnostic procedures undergone until resection of the tumor, including the macroscopic and histological findings, are presented. The diagnosis can be made with certainty by using conventional histology in combination with immunohistochemistry. The tumor cells react positively with antibodies against S-100 protein, NSE, laminin, myelin proteins and myelin-associated glycoproteins. These staining patterns underscore the neural origin of the tumor tissue. In this case a mitotic frequency of two per ten high power fields and focal spindle cells led to the diagnosis of an atypical granular cell tumor, whereas the criteria for a malignant variant were not met.

Purpose of the study was to investigate the mitotic index (MI) and sister chromatid exchange (SCE) levels to identify the mutagenic and carcinogenic effects of sevoflurane (sevoflurane).42 non-smoking male and female turkish patients of ASA-risk I and II were included. The patients received an anaesthesia induction with 8 % sevoflurane in 100 % oxygen ("tidal volume methode") and 0.1 mg/kg BW vecuronium for neuromuscular block and endotracheal intubation. Anaesthesia was maintained with 2.0 - 2.5 sevoflurane in 60 % N(2)O and 40 % O(2). Four 5 ml venous blood samples werde taken: before induction (control), 60 minutes, 24 hours and 5 days after sevoflurane anesthesia. Samples were prepared according to the periferic blood culture assay, modified by Morhead and co-workers, and levels of MI and SCE were examined.60 minutes after sevoflurane-anaesthesia a significant decrease of MI was found compared to controls (p0.01). This depression was lower after 24 hours (p0.05) and reversible after 5 days. SCE increased significantly during 60 minutes of anaesthesia (p0.001), was also lower after 24 hours (5.6 +/- 2.4 vs. 4.4 +/- 1.7) and returned to normal levels after 5 days (p0.05).The application of sevoflurane for anaesthesia may influence the cell division in humans and may have a mutagenic effect on DNA at the cell level, which is reversible.

Morphological, ultrastructural, and immunohistochemical findings of 12 diffuse type-tenosynovial giant cell tumors/pigmented villonodular synovitis are presented compared to 30 localized tenosynovial giant cell tumors (giant cell tumor of tendon sheath). Diffuse-type-tenosynovial giant cell tumor is characterized by a striking vascularisation pattern composed of densely arranged thin-walled, partly slit-like and partly hyalinized small blood vessels within the papillary synovial fronds. These vessels may show abnormal structures with incompletely arranged endothelial cells/pericytes. The fibrohistiocytic tumor cells probably cause considerable compression/distortion or destruction of the small vessels which might be responsible for an increased blood deposition and massive hemosiderosis. Accompanying multinucleated osteoclast-like giant cells seemingly are recruited from circulating blood monocytes. Microhemorrhagic foci with multinucleated giant cells could be detected in 83% of diffuse-type and 67% of localized-type tumors. Apart from the described vessels, typical morphological findings in diffuse-type tenosynovial giant cell tumors included "giant" hemosiderotic granules, (at least 2-3 times the diameter of an erythrocyte) "giant" siderophages, pseudoalveolar clefts and irregularly anastomosing synovial fronds. Neither mitotic rate nor the amount of giant cells/amount of nuclei of giant cells revealed statistically significant differences between localized-type and diffuse-type of tenosynovial giant cell tumor. Immunohistochemically, the diffuse-type exhibited focal expression of CD31 (in 75% of tumors) and calretinin (in 63%) besides CD68-staining.

Desmoid-type fibromatoses (aggressive fibromatoses) represent infiltrative, locally destructively growing soft tissue tumors with a high potential for recurrence. Desmoid tumors of 33 adult patients were analysed regarding clinical and morphological aspects (sex, age distribution, site, size, mitotic rate, tumor microvessel density, surgical margins, additional radiotherapy). Possible statistical correlations were examined using log-rank-tests. No prognostic significance of tumor microvessel density was evident. A correlation between mitotic index (1 or more mitoses per 50 high power fields) and local relapse rate was notably striking, but not statistically significant (log-rank: 0.17). Additional postoperatively applied radiotherapy proved to be statistically significant to avoid local recurrences (log-rank: 0.01). The presented results may indicate an increased risk for local relapse in those desmoid-type fibromatoses which are mitotically active. Postoperative radiotherapy seems to be effective in the treatment of aggressive fibromatosis to avoid tumor recurrence. Differential diagnosis of desmoid-type fibromatosis/aggressive fibromatosis in adulthood include various fibroblastic/myofibroblastic soft tissue tumors such as nodular fasciitis, fibrosarcoma, low-grade fibromyxoid sarcoma, myofibroblastic sarcoma as well as leiomyosarcoma and soft tissue leiomyoma.

Neurotrophic keratitis is a degenerative disease of the cornea caused by reduced corneal innervation. Trauma, tumors, inflammatory lesions and surgical procedures can damage the first branch of the trigeminal nerve on its entire course from brainstem to and within the cornea. Loss or reduction of corneal innervation leads to a reduced aqueous phase of the tear film and due to reduced supply with neurotransmitters/trophic factors also to reduced epithelial healing capacity (impaired mitosis and migration). Combined existence of tear film deficiency and impaired epithelial healing capacity predispose to persistent epithelial defects, corneal ulcers and perforation. Early diagnosis and adequate treatment may prevent this catastrophic chain of events.

GermOnline provides information and microarray expression data for genes involved in mitosis and meiosis, gamete formation and germ line development across species. The database has been developed, and is being curated and updated, by life scientists in cooperation with bioinformaticists. Information is contributed through an online form using free text, images and the controlled vocabulary developed by the GeneOntology Consortium. Authors provide up to three references in support of their contribution. The database is governed by an international board of scientists to ensure a standardized data format and the highest quality of GermOnlines information content. Release 2.0 provides exclusive access to microarray expression data from Saccharomyces cerevisiae and Rattus norvegicus , as well as curated information on 700 genes from various organisms. The locus report pages include links to external databases that contain relevant annotation, microarray expression and proteome data. Conversely, the Saccharomyces Genome Database (SGD), S.cerevisiae GeneDB and SwissProt link to the budding yeast section of GermOnline from their respective locus pages. GermOnline, a fully operational prototype subjectoriented knowledgebase designed for community annotation and array data visualization, is accessible at http://www.germonline.org . The target audience includes researchers who work on mitotic cell division, meiosis, gametogenesis, germ line development, human reproductive health and comparative genomics. (VLID)2213581

Cutaneous cylindromas are benign adnexal tumors that may occur as a solitary lesion or in a multiple familiar pattern. Malignant change is rare. The association of multiple trichoepitheliomas and cylindromas, the so called Brooke-Spiegler Syndrome, is supposed to be inherited in an autosomal dominant manner.A 55 year old woman presented with multiple skin tumors on the scalp, as well as the nasolabial and periauricular area since the age of 20 years. Her daughter and her nephew were also affected. Tumors were surgically removed for cosmetic reasons and showed histological signs of benign cylindromas and trichoepitheliomas. 35 years after diagnosis patient presented with a large exulceration on the right occipital area with intracranial invasion. Staging revealed multiple metastases in both lungs. Patient died 1 month later.Histological examination showed beside zones of massive necrosis multiple mitosis. The jigsaw puzzle pattern and the thick PAS positive basal layer, the striking characteristics of benign cylindromas, were lost. These histological findings and the clinical presentation led to the diagnosis of cylindrocarcinoma.Cylindrocarcinoma is an aggressive tumor with tendency to a local destructive growth and metastases. As malignant transformation of a benign cylindroma occurs more often in the multiple form a close follow-up of patients with multiple cylindromas is necessary. A family study is indicated.

In this study we present mitotic- and meiotic investigations in an anatomical abnormal bovine fetus. The abnormality could be classified as "schistosoma reflexum", which was never described in fetuses in the literature. In the mitotical chromosome preparations from fibroblast cultures the examined fetus showed no chromosomal difference in comparison to the standard synaptonemal complexes (SC) which were prepared from the fetus at the age of 92 days post coitum. In the SCs from the abnormal fetus 43.75% of the investigated cells showed abnormalities such as "loop," "nonhomologue pairing" and "multivalency" in the pairing behavior of the chromosomes. In comparison, less than 5% of the cells in normal embryos showed such abnormalities.