Biomedical subjects

Ulrich Hake

Publications and source records attributed to Ulrich Hake.

3 recordsLinked to original sources

PubMed2005

Aortic valve papillary fibroelastoma.

Cardiac papillary fibroelastoma (CPF) is a rare primary benign cardiac tumor. Before the use of echocardiography, the lesion was identified at autopsy or incidentally during cardiac surgery. CPF is the third most common primary cardiac tumor after atrial myxoma and lipoma, and is the most common tumor of the valvular endothelium. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) permit diagnosis of the tumor in living patients. CPF may be the cause of cerebrovascular or cardiac ischemia due to embolization or occlusion of the vascular ostia. Embolic material may arise from fragments of the tumor itself, or from surrounding thrombus. The case is reported of a patient with CPF of the aortic valve in whom TEE diagnosis was conducted and the tumor removed surgically.

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PubMed2003

Gene expression profiling of human stenotic aorto-coronary bypass grafts by cDNA array analysis.

OBJECTIVE: Aorto-coronary bypass graft disease with its increasing clinical signification represents an unsolved problem in cardiological and heart surgery practice. Late occlusion of autologous saphenous vein grafts is due to medial and neointimal thickening secondary to migration and proliferation of smooth muscle cells (SMCs) and the subsequent formation of atherosclerotic plaques. This study is aimed at identifying differentially expressed genes in human stenotic bypass grafts to detect unknown pathomechanism and to identify novel targets for prophylactic treatment options. METHODS: Stenotic saphenous aorto-coronary bypass grafts (n=5) were retrieved during re-do aorto-coronary bypass surgery. Ungrafted saphenous vein segments (n=5) were taken from the same group of patients and served as internal controls. cDNA samples were prepared and hybridized to cDNA arrays. RESULTS: Some of the differentially expressed genes complied with expected gene expression including upregulation of c-jun and CDK10. In addition, previously unidentified gene expression patterns were detected such as upregulation of HSP70, fibronectin1, erbB3 proto-oncogene and c-myc. To confirm the latter finding, upregulation of c-myc in neointimal and medial SMCs of stenotic graft segments was confirmed by in situ hybridization studies and by immunohistochemistry. CONCLUSION: Gene expression patterns of human stenotic bypass grafts retrieved by re-do operations can be reliably analyzed by cDNA array technology. With this technique, new therapeutic targets in patients could be identified as shown by the findings regarding c-myc. c-myc is a proto-oncogene acting as a transcription factor and blocking c-myc has shown a reduction of neointima formation in animal models. Our study yields a rational for the use of antisense c-myc oligonucleotides to reduce neointima formation and to avoid stenosis in patients.

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PubMedDate not supplied

Proliferative activity in stenotic human aortocoronary bypass grafts.

BACKGROUND: Aortocoronary bypass graft disease is responsible for long-term failure of autologous vein grafts. The analyses of proliferation and cell type characterisation in human bypass grafts harvested during re-do surgery make it possible to investigate the cellular processes leading to bypass graft failure. METHODS: 30 stenotic vein grafts and 25 control veins were explantated during re-do heart surgery procedures. The total area and cell count of the neointima, media and adventitia were calculated computer-assisted. Actively proliferating cells were identified using antibody to Ki-67 and positive cells were determined by double-label immunocytochemistry with SMC alpha-actin, CD 31 (endothelial cells), CD 68 (macrophages) and CD 45 (T-lymphocytes). RESULTS: Active proliferation was detected in different cell types with an average proliferation index of 0.15%, 0.18% and 0.086% for neointima, media and adventitia. Only 9% of proliferating cells in the neointima were SMC (not identified cells 40%); correspondingly, 14% SMC (not identified cells 33%) were detected in the media. Endothelial cells turned out to be the predominant proliferating cell type in all sections of the vessel wall. CONCLUSION: Proliferation in our series of stenotic vein grafts occurred at a low level, but was significantly higher compared to native control veins. While proliferation may play an important role in early lesions, our data clearly show low proliferation activity in advanced graft lesions. The identification of proliferating macrophages and T-lymphocytes implicate an additional inflammatory component in the development of human bypass graft disease. SUMMARY: To clarify the role of cellular proliferation in human aortocoronary bypass grafts, we characterized the cellular composition and proliferation index in 30 stenotic saphenous vein grafts in comparison to 25 native veins. Proliferation in our series of stenotic vein grafts occurred at a low level, but was significantly higher compared to native control veins.

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