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  • Megakaryocytes  (6)
  • Chronic myeloproliferative disorders  (3)
  • 1
    ISSN: 1432-2307
    Keywords: Chronic myeloproliferative disorders ; Thrombocytosis ; Primary Thrombocythaemia ; Granulo ; Erythrocytopoiesis ; Reticulin Fibers ; Circular Deviation ; Histomorphometry ; Bone marrow biopsies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histomorphometric analysis was performed on trephine biopsies of the bone marrow in 55 patients with chronic myeloproliferative disorders (CMPDs) and marked thrombocytosis (platelet count exceeding 600 × 109/l). This study aimed at discriminating primary (essential) thrombocythaemia (PTH) from the various other subtypes of CMPDs presenting with thrombocytosis. Following the diagnostic requirements postulated by the Polycythemia-vera-Study-Group for PTH and polycythaemia vera rubra (P.vera) and the generally accepted criteria for the establishment of chronic myeloid leukaemia (CML) and agnogenic myeloid metaplasia (AMM), our cohort of 55 patients was divided into the following subgroups: CML (16 cases), P.vera (11 cases), AMM (13 cases) and finally PTH (15 cases). Histomorphometric measurements revealed that PTH was distinguishable from the other subtypes of CMPDs with respect to several histological variables: patients with PTH had a normal amount of neutrophilic granulo- and erythrocytopoiesis as well as a non-increased content of reticulin (argyrophilic) fibers in contrast to the findings in CML, P.vera and of course AMM. Moreover, sizes of megakaryocytes and their nuclei were significantly greater in PTH and internalization of haematopoietic cells (emperipolesis) was more frequently encountered in comparison with the other subtypes of CMPDs. Deviation of the circular perimeter of megakaryocyte shape was most prominently expressed in CML and AMM, and consequently generated an increased number of a-nuclear cytoplasmic fragments. In contrast to this feature aberration of the nuclei from a circular outline occurred in a less pronounced way in CML, but was excessive in P.vera, AMM and PTH. Our morphometric evaluation demonstrates that certain histological features may serve as a valuable aid in discriminating PTH from the other occasionally thrombocythaemic subtypes of CMPDs.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2307
    Keywords: Megakaryocytes ; Sinus wall ; Transmural migration ; 3D-reconstruction ; Double-immunostaining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using sequential double-immunostaining and a newly-developed three-dimensional (3D-) reconstruction technique on serially cut sections from bone marrow trephines, we studied the transmural passage of megakaryocytes through the sinus wall. Biopsies derived from patients with primary (idiopathic) osteomyelofibrosis were exposed to monoclonal antibody against type IV collagen to delineate the sinus walls and also the frequently thickened basement membrane. Staining with the primary antibody was followed by Y2/51 (CD61) to identify all elements of megakaryopoiesis. In most instances serial sectioning and 3D-reconstruction revealed an amoeboid shape of megakaryocytes and a tandem-like arrangement in close spatial contact with the abluminal surface of the sinus wall. Preceded by formation of cytoplasmic processes, straight penetration of entire megakaryocytes through gaps in the sinus walls into the lumen was seen. Where collagen deposits apparently presented a barrier, a mole-like tunnelling through the basement membrane material (type IV collagen) was recognizable. Our findings are in keeping with the assumption that megakaryocyte locomotion is an essential requirement for normal thrombocytogenesis.
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  • 3
    ISSN: 1432-0584
    Keywords: Key words CML ; Myelofibrosis ; Dynamics ; Megakaryocytes ; Morphometry ; Interferon ; Busulfan ; Sequential bone marrow biopsies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To evaluate treatment-related changes of the reticulin stain-measured fibrosis in Ph1+-CML, a clinicopathological study was performed on sequential trephine biopsies of the bone marrow following either interferon (IFN) or busulfan (BU) monotherapy. Using the monoclonal antibody CD61 for the identification of megakaryopoiesis and Gomori's silver impregnation method, number of megakaryocytes and density of argyrophilic (reticulin and collagen) fibers were determined by morphometry. We studied specimens from 26 patients with IFN-alpha 2b (including nine patients with additional IFN gamma) therapy and from 23 patients who had received BU. In both groups, repeated bone marrow biopsies (total 125) revealed a significant increase in the fiber content, as well as in the number of megakaryocytes during treatment. To assess the dynamics of myelofibrosis more precisely, computation of differences in the degree of fiber density between the first and last examination was carried out. Regarding the considerable variations in the biopsy intervals, a so-called myelofibrosis progression index (MPI) was calculated. Following this rationale, we were able to demonstrate that, in comparison to the BU-group, speed of progression of bone marrow fibrosis was significantly increased in CML patients treated with IFN. Preliminary statistical analysis indicated a relationship between myelofibrosis on admission, which was always associated with increased growth of megakaryocytes, and the MPI with survival. Even when these parameters were regarded, prognosis was significantly more favorable in the IFN-treated patients. The failure of IFN and BU to inhibit the evolution of myelofibrosis may be related to several conversely acting pathomechanisms. Among others, the inability of both therapeutic agents to reduce the number of megakaryocytes more effectively should be taken into consideration.
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  • 4
    ISSN: 1432-0584
    Keywords: Key words Chronic myeloproliferative disorders ; Erythroid precursors ; Neutrophil granulopoiesis ; Megakaryocytes ; Macrophages ; Myelofibrosis ; Enzyme-immunohistochemistry ; Morphometry ; Bone marrow biopsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The aim of this review is to evaluate morphological characteristics of the different subtypes of chronic myeloproliferative disorders (MPDs) derived by applying immunohistochemical and morphometric techniques to bone marrow biopsies and to combine these results with relevant clinical parameters. In comparison to control specimens, a significant decrease in erythroid precursors is determinable in chronic myeloid leukemia (CML), while this cell lineage is most prominent in polycythemia vera (PV) and moderately to markedly reduced in idiopathic myelofibrosis (IMF). On the other hand, neutrophilic granulopoiesis shows a predominance in CML and a relevant increase in PV, but no conspicuous changes are detectable in essential thrombocythemia (ET). CML is characterized by a prevalent growth of dwarflike micromegakaryocytes, occurring in particular in the so-called megakaryocyte-rich subtypes (about 30%). This finding differs significantly from the pleomorphous aspect, i.e., clusters of small to giant-sized megakaryocytes in PV and the grossly abnormal (dysplastic) appearance of this cell lineage in patients with IMF. Similar cytological abnormalities of megakaryopoiesis consistent with maturation defects are never encountered in ET. The incidence of mature (resident) macrophages (phagocytic reticular cells) is significantly enhanced in IMF in comparison to the other MPDs and controls. Moreover, there is a striking difference in the density of reticulin-collagen fibers, ranging from normal (ET) to extreme values (IMF). In IMF more than 80% of the patients present with some degree of myelofibrosis-osteosclerosis at diagnosis, while the rest show an initial prefibrotic, hypercellular stage. This feature deserves special attention since, when accompanied by thrombocythemia, it may simulate ET. Sequential bone marrow biopsies in patients with IMF disclose that evolution of myelofibrosis is progressive, but occurs at a variable and unpredictable speed. A synoptical approach regarding clinical diagnosis and histological subtyping of MPDs is explicitly recommended and demonstrated by sets of diagnostic criteria. This rationale requires equal consideration of laboratory data and morphology by clinicians to include well-defined subtypes of MPDs into prospective management studies. Furthermore, it may even warrant follow-up studies and repeated bone marrow examinations in initially unclassifiable cases.
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  • 5
    ISSN: 1432-0584
    Keywords: CML ; Myelofibrosis ; Dynamics ; Megakaryocytes ; Morphometry ; Interferon ; Busulfan ; Sequential bone marrow biopsies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate treatment-related changes of the reticulin stain-measured fibrosis in Ph1+-CML, a clinicopathological study was performed on sequential trephine biopsies of the bone marrow following either interferon (IFN) or busulfan (BU) monotherapy. Using the monoclonal antibody CD61 for the identification of megakaryopoiesis and Gomori's silver impregnation method, number of megakaryocytes and density of argyrophilic (reticulin and collagen) fibers were determined by morphometry. We studied specimens from 26 patients with IFN-alpha 2b (including nine patients with additional IFN gamma) therapy and from 23 patients who had received BU. In both groups, repeated bone marrow biopsies (total 125) revealed a significant increase in the fiber content, as well as in the number of megakaryocytes during treatment. To assess the dynamics of myelofibrosis more precisely, computation of differences in the degree of fiber density between the first and last examination was carried out. Regarding the considerable variations in the biopsy intervals, a so-called myelofibrosis progression index (MPI) was calculated. Following this rationale, we were able to demonstrate that, in comparison to the BU-group, speed of progression of bone marrow fibrosis was significantly increased in CML patients treated with IFN. Preliminary statistical analysis indicated a relationship between myelofibrosis on admission, which was always associated with increased growth of megakaryocytes, and the MPI with survival. Even when these parameters were regarded, prognosis was significantly more favorable in the IFN-treated patients. The failure of IFN and BU to inhibit the evolution of myelofibrosis may be related to several conversely acting pathomechanisms. Among others, the inability of both therapeutic agents to reduce the number of megakaryocytes more effectively should be taken into consideration.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 16 (1995), S. 128-138 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Dreidimensionale Rekonstruktion ; Lichtmikroskopie ; Serienschnitte ; Megakaryozyten ; Primäre Osteomyelofibrose ; Knochenmark ; Key words Three-dimensional reconstruction ; Light microscopy ; Serial sections ; Megakaryocytes ; Primary osteomyelofibrosis ; Bone marrow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Computer-based three-dimensional reconstruction of serially cut light microscopic sections is being increasingly used in medical and biological research. Compared with conventional two-dimensional evaluation of histological sections, complex histotopographical relationships and structural details are easy to assess and could be imposingly visualized on the graphics screen. Because of the rapid progress in modern computer hardware, uncomplicated and fast reconstruction systems are available on standard personal computers. Therefore, 3D reconstruction is applicable for a wide range of investigations that warrant 3D exploration. Own results are presented and the principles of 3D reconstruction, as well as the problems and difficulties in this new technique, are discussed. The complex ameboid morphology of megakaryocytes in bone marrow of primary (idiopathic) osteomyelofibrosis is examined with this new method in combination with selective immunohistochemical staining procedures. 3D reconstruction can visualize the complexity of cytoplasmic and nuclear formation impressively. Moreover, the models generated permit exact quantitative measurements of cell morphology. The technique presented is a powerful tool for anatomical-morphological investigations and can furthermore increase our comprehension of complex histomorphological objects.
    Notes: Zusammenfassung Computergestützte dreidimensionale Rekonstruktionsverfahren von lichtmikroskopischen Serienschnitten haben sich in den letzten Jahren in allen Bereichen der medizinisch-biologischen Forschung etablie-ren können. Im Vergleich zur konventionellen zweidimensionalen Schnittbetrachtung lassen sich komplexe histotopographische Beziehungen sowie Strukturcharakteristika besser erfassen und auch eindrucksvoll darstellen. Aufgrund der schnell fortschreitenden Entwicklung im Bereich der Computertechnik sind heutzutage Rekonstruktionssysteme auch auf preisgünstigen Rechnersystemen verfügbar, so daß sich dieser neuen Methode ein zunehmendes Anwendungsgebiet erschließt. Anhand von eigenen Befunden werden die Grundlagen der 3 D-Rekonstruktion besprochen sowie Schwierigkeiten und Probleme dieser neuen Technik diskutiert. In Kombination mit kontrastreichen und selektiven immunhistochemischen Färbungen wird beispielhaft die komplexe amöbenartige Morphologie der Megakaryozyten bei der primären (idiopathischen) Osteomyelofibrose durch lichtmikroskopische Serienschnitte aus dem Knochenmark vorgestellt. Die erzeugten 3 D-Modelle vermitteln einen plastischen Eindruck von der Komplexität der Zell- und Kernstrukturen dieser Zellen und stellen die Basis für exakte quantitative Analysen der Zellmorphologie dar. Die vorgestellte Technik beinhaltet ein ergänzendes Werkzeug für anatomisch-morphologische Analysen und ist in der Lage, entscheidende Erkenntnisse bei der Untersuchung vielschichtiger histomorphologischer Objekte zu liefern.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 21 (2000), S. 39-54 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Chronische myeloische Leukämie ; Megakaryozyten ; Fasern ; Erythropoese ; Makrophagen ; Klinische Befunde ; Immunhistochemie ; Knochenmarkbiopsie ; Key words Chronic myelogenous leukemia ; Megakaryocytes ; Fibers ; Erythroid precursors ; Macrophages ; Clinical findings ; Immunohistochemistry ; Morphometry ; Bone marrow biopsies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary An immunohistochemical and morphometric study was performed on bone marrow biopsies in 604 patients with chronic myelogenous leukemia (CML) to compare morphological and clinical features and to evaluate effects of interferon (IFN) and chemotherapy. Following morphometry significant correlations were calculated between number of CD61+ megakaryocytes, including their precursors with fiber density. This finding is in line with the close functional relationship between megakaryopoiesis and fibroblasts regarding the complex pathomechanism of myelofibrosis. The latter was observed in about 28% of patients already at diagnosis. In a similar way, the frequency of CD68+ macrophages was correlated with the amount of Ret40f+ nucleated erythroid precursors, implicating an involvement of this cell lineage in iron turnover, hemoglobin synthesis, and degradation of the expelled nuclei from normoblasts. The (α-D-galactosyl residue-expressing) Pseudo-Gaucher cells were detectable in 30% of pretreatment specimens. Moreover, significant associations were calculable between reduction in erythropoiesis or increase in fibers with clinical features such as hemoglobin level, percentages of myelo- and erythroblasts in the peripheral blood, and spleen size. These variables are in keeping with more advanced stages of CML. Based on our morphometric evaluations, a classification into three different histological subgroups: granulocytic, megakaryocytic, and myelofibrotic was carried out. This simplified staging system was correlated with corresponding sets of hematological data. Sequential biopsies in 173 patients with monotherapy by IFN, hydroxyurea (HU), or busulfan (BU) revealed a fibrogenic effect of IFN in contrast to a fiber-reducing property of HU. The dynamics of myelofibrosis and changes of major cell lineages during treatment were readily demonstrable by calculating corresponding indices. These included the ratios between quantitative differences of corresponding variables at repeated examinations and time. Thus, in patients with complete hematological remission following IFN administration, regeneration of erythropoiesis was found to be accompanied by an increase in the total number of CD68+ macrophages, including activated subpopulations. Histological subgroups showed a transition from a (nonfibrotic) granulocytic and megakaryocyte pattern to the myelofibrotic subtype in about 40% of patients. This change was opposed to a numerical reduction in the myelofibrotic subtype which occurred in 17 patients (36%), but predominantly in those under HU therapy. In conclusion, the striking heterogeneity of bone marrow features in CML warrants a careful morphological evaluation of trephine biopsies and appropriate means of processing to achieve relevant correlations with clinical data and, thus, allows a more elaborate insight into the dynamics of the disease process.
    Notes: Zusammenfassung Bei 604 Patienten mit einer chronischen myeloischen Leukämie (CML) wurde anhand von Beckenkammbiopsien eine immunhistochemische und morphometrische Studie durchgeführt, um morphologische und klinische Befunde miteinander zu vergleichen und die Auswirkungen der Interferon- (IFN) und Chemotherapie abzuklären. Anhand der morphometrischen Analyse konnten signifikante Korrelationen zwischen der Anzahl CD61+-Megakaryozyten einschließlich ihrer Vorläuferzellen mit der Faserdichte berechnet werden. Dieser Befund spiegelt die enge funktionelle Beziehung zwischen der Megakaryopoese und den Fibroblasten im Hinblick auf den komplexen Pathomechanismus der Myelofibroseentstehung wider. Diese war bei etwa 28% der Patienten bereits zum Diagnosezeitpunkt zu beobachten. In ähnlicher Weise war die Anzahl der CD68+-Makrophagen mit der Menge an Ret40f+-kernhaltigen erythropoetischen Vorläuferzellen korreliert, was durch die Einbindung dieser Zellinie in den Eisenstoffwechsel, die Hämoglobinsynthese sowie den Abbau der ausgestoßenen Normoblastenkerne in Zusammenhang gebracht werden kann. Die (α-D-Galaktosylreste-expremierende) Pseudo-Gaucherzellen ließen sich in 30% der Biopsien vor Behandlung nachweisen. Weiterhin konnten signifikante Beziehungen zwischen einer Reduktion der Erythropoese oder einer Zunahme der Verfaserung mit klinischen Parametern wie dem Hämoglobinspiegel, dem Anteil an Myelo- und Erythro-Normoblasten im peripheren Blut und der Milzgröße berechnet werden. Diese Variablen kennzeichnen offensichtlich mehr fortgeschrittene Stadien der CML. Entsprechend unserer morphometrischen Auswertung wurde eine Klassifikation in drei unterschiedliche histologische Subgruppen vorgenommen: granulozytisch, megakaryozytisch und myelofibrotisch. Dieser vereinfachten histologischen Einteilung waren entsprechende hämatologische Daten zuzuordnen. Sequenzbiopsien an 173 Patienten, die eine Monotherapie mit IFN, Hydroxyurea (HU) oder Busulfan (BU) erhielten, zeigten einen fibrogenetischen Effekt von IFN im Gegensatz zu einer eher faserreduzierenden Eigenschaft von HU. Die Dynamik der Myelofibroseentwicklung und die entsprechende Veränderungen der hauptsächlichen Zellinien während der Behandlung ließen sich am besten durch eine Kalkulation von Indizes verdeutlichen. Diese beinhalteten das Verhältnis aus quantitativen Unterschieden der einzelnen Variablen in den wiederholt durchgeführten Entnahmen und den zugeordneten zeitlichen Differenzen. So war bei Patienten mit einer kompletten hämatologischen Remission nach IFN-Gabe die Regeneration der Erythropoese zusammen mit einem Anstieg in der Anzahl CD68+-Makrophagen einschließlich ihrer aktivierten Subpopulation auszumachen. Die histologischen Subgruppen ließen bei fortlaufenden Untersuchungen einen Übergang sowohl von einem (nicht verfaserten) granulozytären wie auch megakaryozytären Subtyp in eine myelofibrotische Gruppe bei etwa 40% der Patienten erkennen. Dieses Phänomen stand im Gegensatz zu einer anzahlmäßigen Reduzierung des myelofibrotischen Typs vor allem bei Patienten unter HU-Therapie in 17 Fällen (36%). Zusammengefaßt erfordert die auffallende Heterogenität der Knochenmarkbefunde bei der CML eine sorgfältige morphologische Auswertung von Biopsien mit geeigneten Methoden, um relevante Korrelationen zwischen klinischen Daten zu berechnen und somit einen besseren Einblick in die Dynamik der Krankheitsentwicklung zu gewinnen.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 21 (2000), S. 31-38 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Thrombozytose ; Thrombozythämie ; Chronische myeloproliferative Erkrankungen Megakaryopoese ; Myeloisches Stroma ; Key words Thrombocytosis ; Thrombocythemia ; Chronic myeloproliferative disorders ; Megakaryopoiesis ; Myeloid stroma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Differentiation of an elevated, repeatedly determined platelet count (≥500×109/l) includes the discrimination between reactive causes generated by a variety of underlying conditions and a neoplastic myeloprolifera-tive disorder (CMPD). In addition to clinical findings, the evolution of laboratory data during follow-up and histology of the bone marrow exerts a significant diagnostic impact. Characteristic features are not only expressed by hematopoiesis, but also by the myeloid stromal compartment. While the megakaryocyte-rich subtype of chronic myeloid leukemia (CML) and the 5q– syndrome (MDS) are dominated by abnormal micromegakaryocytes, in polycythemia vera (PV) this cell lineage reveals a pleomorphous appearance. In essential thrombocythemia (ET), a prevalence of giant megakaryocytes with deeply lobulated (staghorn-like) nuclei may be encountered. A clear-cut discrimination of ET from early (hypercellular) stages of idiopathic (primary) myelofibrosis (IMF) presenting with thrombocythemia becomes possible, provided the conspicuous atypical features of megakaryopoiesis characterizing the latter entity are taken into account. Moreover, CML displays a predominance of the granulocytic lineage whereas PV shows a panmyelosis or trilineage proliferation, involving erythropoiesis, in particular. In contrast, erythropoiesis is markedly reduced in CML and to a lesser degree also in IMF. In CMPDs extreme values of iron deposits may be found, ranging from a total lack (PV) to minor amounts (CML) and a normal staining reaction (ET). Similar results are exhibited regarding reticulin fibrosis, which is usually not present in ET, rarely observed in PV and detectable to a variable degree in CML and IMF.
    Notes: Zusammenfassung Die Differentialdiagnose eines erhöhten Thrombozytenwertes (≥500×109/l), der insbesondere bei wiederholter Bestimmung gefunden wird, beinhaltet eine Abgrenzung zwischen reaktiven Ursachen im Rahmen ganz unterschiedlicher Grundleiden und einer neoplastischen bzw. myeloproliferativen Systemerkrankung (CMPE). Neben hämatologischen Befunden, vor allem jedoch der Entwicklung der einzelnen Laborparameter im Verlaufe der Erkrankung kommt der Histopathologie des Knochenmarks eine wegweisende diagnostische Bedeutung zu. Charakteristische Veränderungen betreffen nicht nur die Megakaryopoese, sondern auch die übrigen Zellreihen und das Interstitium. Während bei dem megakaryozytenreichen Subtyp der chronischen myeloischen Leukämie (CML) und beim 5q–-Syndrom (MDS) abnorm differenzierte Mikromegakaryozyten vorherrschen, ist die Polycythämia vera (PV) durch einen pleomorphen Aspekt dieser Zellreihe und die essentielle Thrombozythämie (ET) durch zahlreiche Riesenformen gekennzeichnet, die einen stark gelappten Kern (sog. Hirschgeweih-Kerne) aufweisen. Die klare Trennung einer ET von thrombozythämisch verlaufenden Formen der idiopathischen Myelofibrose (IMF) ist durchaus möglich, vorausgestzt man beachtet die ausgeprägten Atypien der Megakaryopoese, welche letztere Entität auszeichnen. Zudem besitzt die CML eine vorherrschende granulozytäre Zellreihe, während die PV durch eine trilineare Proliferation (Panmyelose) mit prominenter erythropoetischer Proliferation gekennzeichnet ist. Eine signifikante Reduktion dieser Zelllinie ist bei der CML und weniger bei der IMF vorhanden. Die CMPE lassen eine deutliche Spannbreite der Retikulumzellsiderose erkennen, die von fehlendem Eisenspeicher (PV) über ganz spärliche Ablagerungen (CML) bis hin zur Normalverteilung (ET) reicht. Ähnliche Befunde sind hinsichtlich einer (retikulären) Myelofibrose zu erheben, die gewöhnlich bei der ET fehlt, vereinzelt bei der PV besteht und bei der CML und IMF in ganz unterschiedlicher Ausprägung vorhanden ist.
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  • 9
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Apoptose ; Proliferation ; Hämatopoetischer Zellumsatz ; Topoisomerase II α ; PCNA ; Chronische myeloproliferative Erkrankungen ; Prognose ; Reaktive Läsionen ; Key words Apoptosis ; Proliferation ; Hematopoietic turnover index ; Topoisomerase II α ; PCNA ; Chronic myeloproliferative disorders ; Prognosis ; Reactive lesions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Apoptosis and proliferation are important regulators of normal development and homeostasis in the bone marrow. Therefore, dynamics of hematopoiesis is mainly defined by these two parameters. However, since only few data are available from previous studies, we performed a retrospective analysis to elucidate some aspects of this complex pathomechanism. A total of 400 patients with chronic myeloproliferative disorders (CMPDs) and corresponding reactive bone marrow lesions were enrolled into this study. Apoptosis was detected in bone marrow tissue by the ISEL-technique and topoisomerase II α expression was demonstrated by the monoclonal antibody Ki-S1. Furthermore, by determination of the proliferating-cell nuclear antigen labeling (PCNA) index, we were able to calculate the proportion of cells in the G2/M phase, because both nuclear antigens are expressed in different phases of the cell cycle. Patients with IMF, PV, and ET revealed a normal range of apoptosis, whereas in chronic myeloid leukemia (CML) a significant increase could be observed. On the other hand, IMF and PV were characterized by a raised proliferative activity. Dynamics of hematopoiesis was assessed by calculation of the so called hematopoietic turnover index. In CML and reactive lesions no alterations of this parameter were detectable, but IMF and PV showed a significant increase. Survival analysis disclosed a relevant worsening of life expectancy for patients with reduced apoptosis and proliferation. In conclusion, our in-situ results confirm and extend previous experimental data on hematopoietic cell kinetics. In this context, a greater regenerative capacity of hematopoiesis may be reflected by an increased rate of apoptosis and/or proliferation and therefore is associated with a more favorable outcome.
    Notes: Zusammenfassung Apoptose und Proliferation stellen im Rahmen einer funktionsgerechten Regelung der Hämatopoese einen integralen Bestandteil für die Aufrechterhaltung des zellulären Gleichgewichts im Knochenmark dar. Insofern ist die Dynamik des hämatopoetischen Zellumsatzes durch diese beiden Parameter gekennzeichnet. Da weiterführende Untersuchungen in dieser Hinsicht lediglich vereinzelt am Knochenmark durchgeführt worden sind, haben wir im Rahmen einer retrospektiven Analyse versucht, einige Aspekte dieses komplexen Mechanismus zu beleuchten. Insgesamt wurden 400 Patienten mit chronischen myeloproliferativen Erkrankungen (CMPE) sowie korrespondierenden reaktiven Veränderungen in die Untersuchung aufgenommen. Neben dem direkten Nachweis der Apoptose im Knochenmark durch die ISEL-Technik haben wir die Topoisomerase II α Expression mittels des monoklonalen Antikörpers Ki-S1 gemessen. Zusätzlich konnten wir durch die Bestimmung der PCNA-Markierung aufgrund der Zellzyklus-spezifischen Färbereaktion beider nukleärer Antigene den Anteil der in G2-/M-Phase befindlichen Zellen ermitteln. Während die IMF, die PV sowie die ET eine im Normbereich liegende Apoptoserate erkennen ließen, war dieser Wert bei der CML signifikant erhöht. Auf der anderen Seite wiesen IMF und PV eine deutlich gesteigerte proliferative Aktivität im Knochenmark auf. Bei der Berechnung eines hämatopoetischen Zellumsatz Index (HZI) zeigten diese beiden CMPE-Subtypen einen signifikanten Anstieg, wohingegen bei der CML sowie den reaktiven Läsionen keine relevante Verschiebung dieses Parameters festzustellen war. Im Rahmen prognostischer Analysen hatten IMF und PV Patienten mit reduzierter Proliferation und Apoptoserate jeweils eine signifikant kürzere Überlebenszeit. Unsere in-situ Ergebnisse erweitern und bestätigen vorausgegangene experimentelle Studien zur hämatopoetischen Zellkinetik. Darüber hinaus lassen sich aus unseren Daten prognostische Überlegungen ableiten, da insbesondere bei der PV und IMF Apoptose und Proliferation signifikanten Einfluß auf das Überleben der Patienten hatten. In diesem Zusammenhang spiegelt eine vermehrte Apoptose- und Proliferationsrate im Knochenmark offenbar eine größere regenerative Kapazität der Hämatopoese wieder und könnte daher für einen günstigeren Verlauf verantwortlich gemacht werden.
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