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Biomedical subjects

L Haenen

Publications and source records attributed to L Haenen.

9 recordsLinked to original sources

Balloon-expandable, radially reinforced ePTFE relining of the superficial femoral artery after remote endarterectomy.

AIM: The aim of this paper was to evaluate the mid-term results of remote endarterectomy and balloon-expandable, radially reinforced ePTFE endograft uplining of the superficial femoral artery (SFA) for long occlusions. METHODS: One hundred and two limbs in 92 patients were included in this prospective, multicenter study. Indications were disabling claudication (n=74), restpain (n=10) and tissue loss (n=16) due to an SFA occlusion of at least 10 cm in length. Remote endarterectomy of the SFA using a modified ringcutter in an over-the-wire technique, was followed by implantation of a balloon-expandable Enduring endovascular graft. Control visits were performed at 1, 3 and 6 months postprocedure and every half year from then on. Follow-up protocol included physical examination, Doppler ankle-brachial index measurement and, in case of doubt, duplex examination. RESULTS: A technical success rate of 98% was achieved. Mean follow-up was 36 months. Four patients were lost to follow-up and 17 patients died of nondevice-related causes. The primary, primary assisted and secondary patency rates were 68%, 73% and 97.5% at 1 year and 50%, 60%, and 89% at 3 years, respectively. CONCLUSION: Although technical success rate is high and early patency rates are good, mid-term results are inferior to those of conventional femoro-popliteal synthetic bypass grafts. In order to become competitive to conventional bypass surgery, further technical refinements will be necessary, especially to overcome the problem of stenoses at the distal transition zone.

Adult↗

Complex thoracic aortic aneurysm: a combined open and endovascular approach.

The authors wish to describe a combined open and endovascular approach to repair a complex thoracic aortic aneurysm. A 72-year-old man with chronic obstructive pulmonary disease, aortic valvular insufficiency and diffuse thoracic aortic aneurysm underwent aortic valve and ascending aorta replacement by a Bentall-procedure and replacement of arch aneurysm using the elephant trunk technique, performed in a first procedure. During the second procedure, endovascular stenting of the descending thoracic aorta was done. Only a few similar case reports have been presented. Endovascular repair after an elephant trunk procedure for complex thoracic aortic aneurysms is an elegant approach to deal with such mega aortas. Further research is necessary to compare open and endovascular repair and to determine long-term follow-up with regard to endoleaks and mortality.

Aged↗

Biventricular assist for severe acute rheumatic pancarditis.

Severe heart failure in acute rheumatic myocarditis is rare. It may be rapidly reversible with treatment, so maximal medical treatment and, if necessary, mechanical support should be given before heart transplantation is considered.

Acute Disease↗

Interleukin 4 and interferon gamma costimulate the expansion of early human myeloid colony-forming cells. Proposal of a model for the regulation of myelopoiesis by interleukin 4 and interferon gamma and its integration with the regulation of the immune response.

We have previously shown that interleukin 4 (IL-4) and interferon gamma (INF-gamma) reciprocally regulate the production of granulocytes and monocytes from mature monopotential hematopoietic progenitor cells, while at the level of the very primitive stem cells IFN-gamma is a selective inhibitor of proliferation and differentiation, and IL-4 has weak stimulatory effects. We investigated the effects of IL-4 and IFN-gamma on the expansion in suspension culture of myeloid colony-forming cells (CFCs) induced by either IL-3 or IL-1+IL-3, using on the one hand more differentiated CD34+HLA-DR strongly positive (HLA-DR++) and on the other hand more primitive Cd34+HLA-DR weakly positive (HLA-DR+/-) human bone marrow cells. It is shown that both IL-4 and IFN-gamma stimulate the IL-3- and IL-3+IL-1-induced expansion of the number of CFCs in the HLA-DR+/- population. In the presence, but not in the absence of IL-1, additive effects of IL-4 and IFN-gamma were seen. We could not demonstrate any IL-3-like effect by IL-4 on early human hematopoietic progenitors. No expansion of CFC number was seen in the HLA-DR++ population. Based on these data and on data which we have published previously, a model for the regulation of myelopoiesis by IL-4 and IFN-gamma is proposed. In this model, IL-4 and IFN-gamma, which are both immune recognition induced inflammatory cytokines, both stimulate the expansion and recruitment of early myeloid progenitors, whereas at the level of their terminal differentiation, the balance between both cytokines determines whether preferentially monocytes/macrophages (IFN-gamma) or granulocytes (IL-4) are being produced. At the level of the most primitive cells, the inhibitory action of IFN-gamma might prevent differentiative exhaustion of the stem cell compartment in situations of hematopoietic stress.

Antibody Formation↗

The combined effects of all-trans retinoic acid and TGF-beta on the initial proliferation of normal human bone marrow progenitor cells.

We investigated the cell kinetic effects of retinoic acid (RA) and the functional interaction between RA and TGF-beta on normal human bone marrow progenitor cells (CD34+). Cell cycle progression throughout the first three consecutive cell cycles and alterations in cell kinetic responses were measured using the BrdU-Hoechst quenching technique. RA stimulates the IL-3-induced growth by additionally recruiting quiescent stem and progenitor cells out of the G0/G1-phase and by increasing the cell cycle traverse rate. In contrast, TGF-beta addition resulted in a significant decrease in the number of proliferating cells. Simultaneous addition of RA and TGF-beta resulted in a stronger inhibition compared to addition of TGF-beta alone. Preincubation experiments further showed that RA is capable of sensitizing the progenitors to the inhibitory action of TGF-beta: the inhibitory effect of TGF-beta was significantly increased when cells were pretreated with RA. These data show that, in combination with IL-3, RA additionally stimulates quiescent bone marrow progenitors in a simultaneous way, and that it increases sensitivity of the progenitors to the inhibitory action of TGF-beta. The combination of RA and TGF-beta on normal and leukemic hematopoiesis has to be further investigated, since this combination may possibly provide additional therapeutic benefit.

Antigens, CD34↗

Interferon gamma selectively inhibits very primitive CD342+CD38- and not more mature CD34+CD38+ human hematopoietic progenitor cells.

To assess the effects of interferon gamma (IFN-gamma) on very primitive hematopoietic progenitor cells, CD34(2+)CD38- human bone marrow cells were isolated and cultured in a two-stage culture system, consisting of a primary liquid culture phase followed by a secondary semisolid colony assay. CD34(2+)CD38- cells needed at least the presence of interleukin 3 (IL-3) and kit ligand (KL) together with either IL-1, IL-6, or granulocyte-colony-stimulating factor (G-CSF) in the primary liquid phase in order to proliferate and differentiate into secondary colony-forming cells (CFC). Addition of IFN-gamma to the primary liquid cultures inhibited cell proliferation and generation of secondary CFC in a dose-dependent way. This was a direct effect since it was also seen in primary single cell cultures of CD34(2+)CD38- cells. The proliferation of more mature CD34+CD38+ cells, however, was not inhibited by IFN-gamma, demonstrating for the first time that IFN-gamma is a specific and direct hematopoietic stem cell inhibitor. IFN-gamma, moreover, preserves the viability of CD34(2+)CD38- cells in the absence of other cytokines. IFN-gamma could, therefore, play a role in the protection of the stem cell compartment from exhaustion in situations of hematopoietic stress and may be useful as stem cell protecting agent against chemotherapy for cancer.

ADP-ribosyl Cyclase↗

Endoleaks after endoluminal repair of abdominal aortic aneurysms: diagnosis and treatment.

Endoleaks currently present one of the major problems related to endoluminal treatment of abdominal aortic aneuryms (AAA). The incidence and fate of endoleaks stress the importance of long term follow-up. In this article the authors discuss which imaging techniques can best be used for surveillance and how endoleaks should be classified. Furthermore the necessity of treatment as well as treatment options are discussed.

Aortic Aneurysm, Abdominal↗

[The surgical treatment of pulmonary embolism].

Acute pulmonary embolism with major hemodynamic derangement may be treated by thrombolysis or surgically by direct pulmonary embolectomy under cardiopulmonary bypass or by a transvenous method with a steerable aspiration catheter unit. The key to success in massive pulmonary embolism is a quick and correct diagnosis while the vital haemodynamic parameters are maintained by supportive means.

Acute Disease↗