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H E Schaefer

Publications and source records attributed to H E Schaefer.

At least 19 recordsLinked to original sources
PubMed2000

Cloning of PRV-1, a novel member of the uPAR receptor superfamily, which is overexpressed in polycythemia rubra vera.

Polycythemia vera (PV) is a clonal stem cell disorder characterized by hyperproliferation of the erythroid, myeloid, and megakaryocytic lineages. Although it has been shown that progenitor cells of patients with PV are hypersensitive to several growth factors, the molecular pathogenesis of this disease remains unknown. To investigate the molecular defects underlying PV, we used subtractive hybridization to isolate complementary DNAs (cDNAs) differentially expressed in patients with PV versus normal controls. We isolated a novel gene, subsequently named PRV-1, which is highly expressed in granulocytes from patients with PV (n = 19), but not detectable in normal control granulocytes (n = 21). Moreover, PRV-1 is not expressed in mononuclear cells from patients with chronic myelogenous leukemia (n = 4) or acute myelogenous leukemia (n = 5) or in granulocytes from patients with essential thrombocythemia (n = 4) or secondary erythrocytosis (n = 4). Northern blot analysis showed that PRV-1 is highly expressed in normal human bone marrow and to a much lesser degree in fetal liver. It is not expressed in a variety of other tissues tested. Although PRV-1 is not expressed in resting granulocytes from normal controls, stimulation of these cells with granulocyte colony-stimulating factor induces PRV-1 expression. The PRV-1 cDNA encodes an open reading frame of 437 amino acids, which contains a signal peptide at the N-terminus and a hydrophobic segment at the C-terminus. In addition, PRV-1 contains 2 cysteine-rich domains homologous to those found in the uPAR/Ly6/CD59/snake toxin-receptor superfamily. We therefore propose that PRV-1 represents a novel hematopoietic receptor. (Blood. 2000;95:2569-2576)

Adult↗
PubMed2000

[Histologic and hematological findings in CML. A comparative immunohistochemical-morphometric and clinical study on bone marrow biopsies from 604 patients derived from two institutes of pathology (Cologne/Freiburg)].

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 (alpha-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.

Biopsy↗
PubMed2000

[Prognostic factors and survival in chronic myeloproliferative disorders].

The broad spectrum of clinical and hematological as well as histomorphological findings at diagnosis of chronic myeloproliferative disorders (CMPDs) is significantly associated with prognosis. However, in this context the impact of bone marrow histology is still being controversially discussed. This feature applies to CML in particular. Therefore, risk classification is mainly based on clinical data. In order to evaluate the predictive value of bone marrow morphology we performed a retrospective study on a total of 1023 patients with CMPDs. Relative survival rates and a disease-specific loss of life expectancy were calculated to adjust the age- and gender-specific mortality in older patients. Patients with chronic myeloid leukemia (CML) showed an average life expectancy of 5 years, with significantly longer survival times under interferon treatment. In contrast, the ET group did not disclose any relevant reduction in life expectancy. Initial bone marrow fibrosis and a reduction in erythropoiesis were the most important prognostic features in CML. Furthermore, Pseudo-Gaucher cells indicated a favorable outcome in the cohort of patients receiving chemotherapy. On the other hand, peripheral myelo- and erythroblasts were correlated with a worsening in survival. Regarding IMF, a simplified multivariate risk score was constructed, including age, hemoglobin level, platelet and leukocyte counts, and a leuko-erythroblastic blood picture as most important variables. The three risk groups derived showed significantly different survival patterns, but in this calculation bone marrow histology exerted no major influence on survival. On the other hand, initial (prefibrotic) stages of IMF revealed a better prognosis. In conclusion, our results underline the importance of bone marrow morphology in CMPDs, since significant correlations with patients' outcome were calculated. Particularly in CML, myelofibrosis and reduction of erythropoiesis were associated with survival and, thus, must be regarded as important predictive and independent parameters.

Adult↗
PubMed2000

Therapy-related changes of CD20+ and CD45RO+ lymphocyte subsets in chronic myeloid leukemia (CML): an immunohistochemical and morphometric study on sequential trephine biopsies of the bone marrow.

Little information exists about the amount of CD45RO+-T- and CD20+-B-lymphocytes in the bone marrow of patients with Philadelphia chromosome-positive chronic myelogenous leukemia (Ph1+-CML) at presentation or regarding corresponding changes during therapy. On the other hand, quantification of this cell compartment seems to be imperative for two reasons: first, the presumed association of immunocompetent lymphocyte subsets in the expansion of the leukemic cell clone; and second, a speculated relationship with the complex generation of myelofibrosis. Therefore, an immunohistological and morphometric study was performed on 219 representative trephine biopsies of the bone marrow derived from 70 patients with repeated examinations during the course of Ph1+-CML. For the identification of the different lymphocyte populations, the monoclonal antibodies UCHL-1 (CD45RO) and L26 (CD20) were applied on formaldehyde-fixed and decalcified specimens. In comparison to a control group and calculated per hematopoietic cells, the CML bone marrow showed about a 50% decrease in the total amount of lymphocytes. Determination of CD45RO+ and CD20+ subsets revealed a significant enhancement during treatment. Because of the different intervals (range, 10 to 25 mo) between first and last biopsy in the various therapeutic groups, results had to be modified by considering dynamic features. This calculation included changes of the lymphocyte subpopulations related to time. Contrasting the CD45RO+ lymphocytes, a relevant increase in the CD20+ subset could be observed after interferon-a treatment or corresponding combination regimens. No significant correlations were found between fiber density at onset (first biopsy) or development of fibrosis and lymphocyte proliferations in the course of CML. Our results are in keeping with the finding that a proper immune response consistent with an increased lymphocyte growth seems to be associated with a regression of the clonally-transformed cell population. Opposed to a repeatedly discussed pathomechanism, we failed to demonstrate any quantitative relationships between the extent of lymphocyte proliferations and occurrence or progression of myelofibrosis.

Adult↗
PubMed2000

Changing patterns of histological subgroups during therapy of Ph1+ chronic myelogenous leukaemia.

AIMS: Bone marrow histopathology reveals a striking heterogeneity at diagnosis of Philadelphia chromosome positive (Ph1+) chronic myelogenous leukaemia (CML). Based on semiquantitative evaluations of the number of megakaryocytes and the content of fibres, various histological subtypes have been postulated. However, little information exists on whether these groups represent stable categories of the different classification systems and whether therapeutic regimes exert any influence on the putative shift of histological patterns. METHODS AND RESULTS: A retrospective clinicopathological study was performed on 396 bone marrow biopsies derived from 173 patients. There were at least two representative trephines taken at diagnosis and at median intervals of 16 months. Processing of the specimens involved immunostaining with CD61 (megakaryopoiesis) and Ret40f (erythropoiesis) and Gomori's silver impregnation technique. Based on morphometric analysis and in accordance with the general appearance of bone marrow histology three different histological subtypes were distinguished. These consisted of a granulocytic (51 patients), a predominantly megakaryocytic (73 patients) and a myelofibrotic pattern (49 patients). Follow-up biopsies revealed that a significant transition of histological groups occurred and that, independently of treatment modalities, the myelofibrotic category was associated with an unfavourable prognosis. Of the 124 patients without myelofibrosis at onset, 42% later transformed into the myelofibrotic subtype. However, these patients showed no prevalence of either a pre-existing granulocytic or megakaryocytic growth. Myelofibrotic changes were significantly associated with interferon (IFN) and busulfan (BU) therapy. On the other hand, a transition of a myelofibrotic into a nonfibrotic subtype was detectable in 17 of the 49 patients under study and related to hydroxyurea (HU) treatment. CONCLUSIONS: Histological classification systems of bone marrow features in CML do not represent stable patterns, but may be significantly altered by therapy, in particular IFN and HU.

Adult↗
PubMed2000

Effects of chemotherapy (busulfan-hydroxyurea) and interferon-alfa on bone marrow morphologic features in chronic myelogenous leukemia. Histochemical and morphometric study on sequential trephine biopsy specimens with special emphasis on dynamic features.

We performed a retrospective clinicopathologic study on sequential biopsy specimens from 90 patients with Philadelphia chromosome-positive chronic myelogenous leukemia to study therapy-specific effects of busulfan (28 patients), hydroxyurea (32 patients), and interferon-alfa (IFN-alfa; 30 patients). Bone marrow specimens were evaluated by morphometry after silver impregnation and staining with monoclonal antibodies to identify reticulin fibers, nucleated erythroid precursors, megakaryocytes, and macrophages. To compute dynamics of histopathology implicating corresponding changes in time, relevant indices were calculated. Quantification of megakaryocytopoiesis and its precursor cell population showed a significant increase in the IFN-alfa and busulfan groups compared with the hydroxyurea group. These changes were associated with a development of myelofibrosis during therapy. Although a significant increase in fiber density was detectable in the busulfan group, the progression index proved to be twice as high after IFN-alfa therapy. In contrast, a considerable number of patients displayed a regression of myelofibrosis after hydroxyurea treatment. The general association of the megakaryocyte lineage with myelofibrosis was in line with experimental findings. The mature macrophage population and its activated subfraction revealed a marked proliferation (IFN-alfa group) during treatment. Growth and activation of macrophages may be compatible with their putative function during erythrocytopoietic regeneration and with stimulation of their phagocytic properties.

Antineoplastic Agents↗
PubMed2000

Bone marrow features and clinical findings in chronic myeloid leukemia--a comparative, multicenter, immunohistological and morphometric study on 614 patients.

A multicenter, immunohistochemical and morphometric study was performed on diagnostic pretreatment bone marrow biopsies in 614 adult patients with Ph1+ chronic myeloid leukemia (CML) to compare histological features with clinical findings. For identification of megakaryopoiesis we used the monoclonal antibody CD61 and additionally the PAS reaction to determine the subfraction of atypical micromegakaryocytes and precursors. Labelling of erythroid precursors was carried out by a monoclonal antibody directed against glycophorin C. In order to selectively stain macrophages and their activated subset we applied CD68 and the GSA-I lectin. Density of argyrophilic fibers (reticulin plus collagen) was measured following Gomori's silver impregnation method. In accordance with laboratory data morphological variables revealed a comparable amount of congruence in the various groups of CML patients derived from different sources. In about 26% of patients early (reticulin) to advanced (collagen) fibrosis was detectable. Significant correlations were calculated between the extent of myelofibrosis with splenomegaly, anemia and increasing numbers of erythroblasts and myeloblasts in the peripheral blood count. These features were assumed to indicate more advanced stages of the disease process with ensuing transition into myeloid metaplasia and consequently were associated with an unfavorable prognosis. Significant relationships were revealed between the number of CD61+ megakaryocytes and more important, also their precursor fraction with the degree of fibrosis. This result extends previous experimental findings regarding the impact of immature elements of this cell lineage for the generation of myelofibrosis. The significant association of erythroid precursors with the number of mature (resident) macrophages including their activated GSA-I subset may shed some light on their functional involvement in iron turnover and hemoglobin synthesis. A modified histological classification of predominant bone marrow features is introduced. This simplified synthesis staging system (Cologne Classification) is not only associated with certain sets of laboratory data, but also with different survival patterns.

Adult↗
PubMed1999

Familial and metachronous malignant lymphoma: absence of constitutional p53 mutations.

Familial and metachronous aggregations of malignant lymphoma are well-documented, but the molecular basis of a predisposition for development of lymphoma is as yet unclear. Malignant lymphomas have been described as part of the spectrum of neoplasias in Li-Fraumeni syndrome (LFS), which is associated with constitutional mutations of p53. However, p53 germline mutations have also, albeit less frequently, been described in patients not fitting the clinical definition of LFS. To clarify whether a genetic predisposition for lymphoma is associated with constitutional p53 mutations, DNA from normal blood lymphocytes of 12 lymphoma patients with a family history of lymphoma and/or with metachronous lymphoma (median age 37 years) was examined for mutations of p53 exons 4-8. One patient had four first-degree relatives with Hodgkin's disease, acute leukemia, and carcinomas, but the family history did not fulfill criteria of LFS. Four patients with Hodgkin's disease were diagnosed with metachronous non-Hodgkin's lymphoma as a second malignant neoplasm. No constitutional p53 mutations were detected in any of these patients, implying that outside the clinical spectrum of LFS, constitutional p53 mutations are rare in patients with lymphomas.

Adult↗
PubMed1999

Concordant upregulation of type II-TGF-beta-receptor, the cyclin-dependent kinases inhibitor P27Kip1 and cyclin E in human atherosclerotic tissue: implications for lesion cellularity.

Atherosclerosis is a 'response-to-injury' process associated with chronic inflammation, tissue repair and a considerable cell turnover. These growth-related processes are controlled by the 'cell cycle clock' which is composed of cyclin-dependent kinases (Cdks), their activating subunits, the cyclins, and by inhibitors of Cdks (Ckis). P27 is a Cki which associates with cyclin A-Cdk2, cyclin D-Cdk4 and with cyclin E (CE)-Cdk2 complexes thereby abrogating their catalytic activity leading to potent inhibition of late G1 to S-phase transition. Furthermore, TGF-beta1 mRNA and immunoreactivity are locally increased in atherosclerotic lesions. Since TGF-beta1 growth suppressive function in the late G1 phase may be mediated by p27, blocking the catalytic activity of CE-Cdk2 complexes, via the stimulation of TGF-beta-RI and TGF-beta-RII, we investigated the topographical association between TGF-beta-RI, TGF-beta-RII, P27Kip1 and CE by immunohistochemistry in coronary artery segments without atherosclerosis and carotid atheromatous plaques of 11 patients undergoing carotid endarterectomy. P27-immunoreactivity was present in 11/11 atherosclerotic (92.7 +/- 3.3% of the cells) and 5/5 control (80.9 +/- 3.7% of the cells; P < 0.002 versus control) specimens and localized to nuclei of macrophages (CD68-positive), vascular smooth muscle cells (alpha-actin positive), T-lymphocytes (CD3-positive) as well as to the nuclei of endothelial cells. In the atherosclerotic tissue, TGF-beta-RI and TGF-beta-RII-immunoreactivity was present in 11/11 specimens and localized to inflammatory cells and to cells with VSMC-like-morphology. TGF-beta-RI-immunoreactivity was present in 87.4 +/- 5.3% (controls 75.3 +/- 7.48%; n.s.) and TGF-beta-RII-immunoreactivity was present in 83.7 +/- 6.8% (controls 39.5 +/- 7.3%; P < 0.002) of the cells. Double immunolabeling, and investigation of serial sections revealed co-expression of TGF-beta-RI and TGF-beta-RII in virtually all cells positive for P27. In the atherosclerotic specimens, CE-immunoreactivity was present in all specimens in macrophages (CD68-positive), vascular smooth muscle cells (alpha-actin positive) and in endothelial cells in 12.58 +/- 13.58% of the nuclei whereas in the controls CE staining was restricted to 0.19 +/- 0.43% of the cells (P < 0.001). Importantly, as shown by immunofluorescent double-labeling, we found cells expressing P27 that were simultaneously positive for CE. In summary, the present study provides evidence that TGF-beta1 present in human atherosclerotic tissue may mediate its growth suppressive activity also by p27, blocking the activity of CE-Cdk2 complexes. Quantitative analysis revealed that TGF-beta-RII, p27 and CE are concordantly upregulated in the atherosclerotic tissue with chronic inflammation, supporting the view that TGF-beta1, p27 and CE may play an important role in the processes associated with chronic inflammation and cell turnover in advanced human atherosclerotic plaques. Taken together, these results provide a possible link between the chronic inflammation associated with advanced atherosclerosis, the effects of extracellular growth factors and cell cycle control.

Arteriosclerosis↗
PubMed1999

Cystic medial degeneration of the aorta is associated with p53 accumulation, Bax upregulation, apoptotic cell death, and cell proliferation.

OBJECTIVE: To address a potential role for p53, Bcl2 associated protein X (Bax), and apoptosis in the processes associated with cell turnover during cystic medial degeneration (CMD) of the aorta. METHODS: Histochemical, immunohistochemical, biochemical, and morphometric methods were used to assess the presence and distribution of p53 immunoreactivity (p53-IR) and Bax immunoreactivity (Bax-IR), as well as the presence of apoptosis and tissue repair processes. RESULTS: Immunohistochemical staining disclosed evidence for p53-IR in all specimens in 26.1 (11.5)% of vascular smooth muscle cells (VSMCs) (controls 0.8 (1.3)%; p < 0. 001). Bax-IR was present in all specimens in 10 (5.4)% of medial cells (controls 0.3 (0.5)%; p < 0.001). Medial VSMCs (alpha-actin positive) with cytoplasmic staining for an apoptosis specific protein (c-jun/ASP) were present in 20/20 specimens (0.7 (0.6)% of VSMCs, controls 0%, p < 0.001), whereas terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) positive VSMCs were present in 17/20 specimens (1 (1.5)% of VSMCs, controls 0%, p < 0.001). The presence of apoptosis was confirmed by electron microscopy and the demonstration of oligonucleosomal DNA fragments after agarose gel electrophoresis. As shown by double labeling and investigation of serial sections, p53-IR, Bax-IR, c-jun/ASP-IR, and positive TUNEL labeling localised to the same compartments of the aortic media, raising a possible role for p53 and Bax in the triggering of apoptosis of VSMC during CMD. MIB1/Ki-67 positive medial VSMCs (alpha-actin positive) and mesenchymal cells (vimentin positive) were present in all specimens (2.5 (2.8)% of medial cells; controls 0.3 (0.9)%, p < 0.001) mainly in the region around the vasa vasorum, indicating that cell regeneration during CMD may originate mainly from the mesenchyme surrounding the vasa vasorum. CONCLUSION: This study shows that the formal pathogenesis of CMD is characterised by p53 accumulation, Bax upregulation, cell death by apoptosis, and cell regeneration. Nevertheless, the precise stimuli of p53 activation and Bax upregulation as well as the role of p53 and apoptosis in the dissection process itself remain elusive.

Adult↗
PubMed1998

Co-expression of p53 and MDM2 in human atherosclerosis: implications for the regulation of cellularity of atherosclerotic lesions.

Atherosclerosis is a fibroproliferative disease of the arterial intima. It was recently found that wild-type p53 (wt p53) accumulates in human atherosclerotic tissue. Wt p53 is a cell cycle regulator involved in DNA repair, DNA synthesis, cell differentiation, and apoptosis and might therefore make an important contribution to the cellularity of atherosclerotic plaques. The product of the MDM2 gene is a nuclear protein which forms a complex with p53, thereby inhibiting the negative regulatory effects of wt p53 on cell cycle progression. In order to address a potential role of the interaction of p53 with MDM2 for the regulation of cellularity in atherosclerotic tissue, 22 carotid atheromatous plaques from patients undergoing endarterectomy were studied to determine the presence of p53 immunoreactivity (IR), MDM2 IR, cell proliferation as evidenced by MIB1/Ki-67 IR and DNA fragmentation by in situ terminal transferase-mediated dUTP 3' end labelling (TUNEL), as a marker for apoptosis. p53 IR localized to areas with evidence of chronic inflammation (22/22) and was observed in virtually all cell types in 68.79 +/- 7.51 per cent of the nuclei. p53 staining in the control tissue from human internal mammary arteries was present in 0.2 +/- 0.29 per cent of the cells (P < or = 0.002). MDM2 IR was present in all cases (22/22) in macrophages and smooth muscle cells (SMCs) in 60.53 +/- 8.32 per cent of the nuclei (controls: 0.8 +/- 0.65 per cent, P < or = 0.002) and co-localized with p53 IR as shown by examination of adjacent sections and by double immunofluorescence labelling. Importantly, co-immunoprecipitation and western blot analysis revealed that p53 and MDM2 were physically associated, indicating that MDM2-p53 complex formation takes place in vivo in human atherosclerotic tissue. Positive TUNEL staining and MIB1/Ki-67 IR present in 3.01 +/- 1.27 per cent of the nuclei (controls: 0 per cent, P < or = 0.002) localized to the same plaque compartments as p53 IR and MDM2 IR. Thus, the fate of cells with p53 accumulation may depend on the interaction and the stoichiometry of the p53 and MDM2 proteins. Cells were indeed found with strong p53 accumulation and nuclear morphology typical for apoptosis and there were a few MIB1/Ki-67-positive cells with co-expression of MDM2, indicating a possible role for MDM2 in reversing the negative regulatory effects of p53 for cell cycle progression. The nuclear co-localization of p53 IR with MDM2 IR and the co-immunoprecipitation assay indicate the presence of p53-MDM2 complex formation in vivo in human atherosclerotic tissue. The destiny of individual p53 and MDM2-co-expressing cells either to undergo p53-dependent apoptosis or to re-enter the cycle of cell proliferation may depend on the relative ratios of the two proteins. p53 and MDM2 may therefore play an important role in regulating cellularity and inflammatory activity in human atherosclerotic plaques.

Apoptosis↗
PubMed1998

Bronchiolitis obliterans organising pneumonia and primary biliary cirrhosis-like lung involvement in a patient with primary biliary cirrhosis.

A 55-year-old woman with a 6-year history of primary biliary cirrhosis presented with an acute onset of fever, dyspnoea, crackles over both lower lung fields, and diffuse interstitial and bibasilar patchy pulmonary opacities. After exclusion of an infectious aetiology, an open lung biopsy was performed which revealed two histopathological features: (1) bronchiolitis obliterans organising pneumonia and (2) lympho-histiocytic interstitial pneumonitis and destructive bronchiolitis. Treatment response to corticosteroids and azathioprine followed a bimodal pattern with immediate resolution of her initial presenting symptoms and late resolution of residual gas exchange defects.

Adrenal Cortex Hormones↗
PubMed1998

Drug resistance of secondary acute myeloid leukemia with megakaryoblastic features and p190 BCR-ABL rearrangement.

A 46-year-old female presented with acute myeloid leukemia during complete remission of multiple myeloma after extensive treatment with alkylating agents. Leukemic blasts expressed CD34, platelet esterase and gp IIIa. RT-PCR analyses of peripheral blood cells detected a p190 type BCR-ABL rearrangement and high levels of MDR1. The patient expired during neutropenia shortly after induction chemotherapy. Autopsy revealed persistent blasts in the bone marrow, spleen and liver. 'Secondary' acute myeloid leukemia with megakaryoblastic features and p190-type BCR-ABL rearrangement has not previously been reported. The possibility that the combination of a BCR-ABL rearrangement with overexpression of MDR1 may have contributed to the treatment-refractory course is discussed.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Increased tissue endothelin-1-like immunoreactivity in the internal mammary artery of patients with diabetes or hypercholesterolemia modulates the graft flow in the peri-operative period.

OBJECTIVE: Peri-operative ischemic episodes following coronary artery bypass grafting with the internal mammary artery (IMA) are thought to be due to a vasospasm of this conduit. Endothelin-1 (ET-1) is a potent vasoconstrictor by itself and increases the response to other vasoconstrictor stimuli. This study focused on the possible role of an enhanced tissue ET-1-like immunoreactivity in the perioperative reaction of the IMA in patients with diabetes or hypercholesterolemia. METHODS: Specimens of the distal part of the IMA from 46 patients (mean age 58.5 years, four women, 42 men) were studied prospectively. Nine of those patients were diabetic and 26 had evidence of hypercholesterolemia. Another cohort of 20 IMA specimens was stained retrospectively; 10 of those biopsies were from patients that had experienced transient ischemic events peri-operatively in the myocardial area supplied by the IMA. The biopsies were examined histologically and immunohistochemically (rabbit polyclonal ET-1 antiserum, three-step avidin-biotin complex) with regard to their immunoreactivity to tissue ET-1. RESULTS: An immunoreactivity to ET-1 (graded 0-3) was present in 89% of the biopsies. The reactivity was significantly higher in patients with hypercholesterolemia ( 1.92+/-0.74) when compared to controls (1.0+/-0.63) (P = 0.04). The reactivity was also increased in patients with non-insulin-dependent diabetes mellitus (2.1+/-0.79), when compared to controls (P = 0.02). Mostly transient ischemic events in the area supplied by the IMA seemed to occur more frequently when the biopsies revealed a higher immunoreactivity to ET-1. They showed an increased reactivity to ET-1 (2.27+/-0.76) compared to 10 patients with an uneventful peri-operative course (1.66+/-0.71 ) (P = 0.04). CONCLUSIONS: This study provides evidence that the internal mammary artery is not a passive conduit. Vasospasm or vasoconstriction, in particular at its distal end, may occur more frequently in patients with hypercholesterolemia or diabetes, and may lead to post-operative ischemic events.

Biopsy↗
PubMed1998

An immunohistochemical study of endothelin-1 in the human eye.

PURPOSE: Endothelin-1 (ET-1) is a potent vasoconstrictive and neural peptide that has been demonstrated to be present and functionally active and important in the eye. This study was undertaken to examine for the first time the cellular distribution of ET-1 in the whole human eye. METHODS: Twelve human eyes were examined by immunohistochemical staining of paraffin sections, using an anti-ET-1 primary antibody and an ABC-detection system. RESULTS: Endothelin-1-immunoreactivity (ET-1-IR) was detected primarily in the fibrovascular stroma of the iris, ciliary body and choroid, in the retinal blood vessels, the ciliary and optic nerves, and in the corneal and the non-pigmented ciliary epithelium. CONCLUSION: In the eye, ET-1-IR is present in fibrovascular, neural and epithelial structures. Changes in the distribution and concentration of ET-1 may be relevant to a variety of ocular diseases including diabetes mellitus, hypertension, sickle cell disease, optic neuritis, AION, papilledema, corneal ulcer, corneal epithelial dystrophy or after keratoplasty.

Choroid↗
PubMed1997

Topographical association between the cyclin-dependent kinases inhibitor P21, p53 accumulation, and cellular proliferation in human atherosclerotic tissue.

The cell cycle is controlled by cyclin-dependent protein kinases (CDKs). The activity of these enzymes is directed by inhibitors of CDKs. The 21-kD protein product (P21) of the WAF1/CIP1 gene, which can be transactivated by the protein product of the tumor suppressor gene p53, acts as an inhibitor of cyclin-dependent kinases. To assess whether both P21 and p53 may play a role in the control of cellular proliferation in atherosclerotic lesions, the topographical association between p53, P21, and the proliferation marker MIB1/Ki-67, was analyzed by immunohistochemistry in human carotid atheromatous plaques of 26 patients. p53 immunoreactivity (IR) was present in 26 of 26 cases in the nuclei of virtually all cell types (macrophages [MPs], smooth muscle cells [SMCs], endothelial cells [ECs]) in areas with chronic inflammation in 71.08 +/- 8.28% of the nuclei. p53 staining in the control tissue from human coronary arteries was present in 0.3 +/- 0.45% of the cells (P < .002): P21-IR was present in 24 of 26 specimens in 64.38 +/- 10.13% of the cells (controls: 3.8 +/- 1.85%, P < .002) and localized to nuclei of MPs (CD68 positive) and SMCs (alpha-actin positive), as well as ECs of microvessels present in 21 specimens (21 of 21) and luminal ECs present in 18 specimens (16 of 18). As shown by double labeling, P21-IR colocalized with p53-IR in most MPs (24 of 24), intimal SMCs (22 of 24), ECs of microvessels (19 of 21), and luminal ECs (10 of 16). Interestingly, few p53-positive cells did not show simultaneous P21-IR, and, conversely, not all P21-positive cells demonstrated p53-IR. MIB1/Ki-67-positive cells were identified in 21 of 26 tissue specimens in 3.53 +/- 1.79% of the nuclei (controls: 0%, P < .002) and localized principally to MPs bordering the atheromatous lipid core (21 of 26) and to a few scattered SMCs (16 of 26), ECs of microvessels (13 of 21), and luminal ECs (2 of 18). Most importantly, none of the cells coexpressing P21 and p53 were positive for MIB1/Ki-67-IR, indicating the absence of proliferating activity. In summary, this study demonstrates that P21-IR is present in the atherosclerotic plaque and colocalizes with p53 in most MPs, SMCs, and ECs. The lack of proliferation markers in cells coexpressing p53 and P21 suggests that transcriptional activation of the WAF1/CIP1 gene by p53 may be involved in the control of cellular proliferation in advanced human atherosclerotic plaques.

Arteriosclerosis↗