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Biomedical subjects

B Birmelé

Publications and source records attributed to B Birmelé.

10 recordsLinked to original sources
PubMed2001

Salvage of immature forearm fistulas for haemodialysis by interventional radiology.

BACKGROUND: The goal of this article is to assess the value of endovascular techniques for the salvage of fistulas that fail to mature. METHODS: Over a 6-year period, 52 dysfunctional and 17 thrombosed immature forearm fistulas (mean age 10 weeks) were treated by interventional radiology. Angiography was performed by puncture of the brachial artery but dilation of underlying stenoses was performed after cannulation of the fistula itself, whenever possible, with a balloon never smaller than 5 mm. Embolization or ligation of any type of vein was never indicated and never performed. For thrombosed fistulas, significant clots were removed by manual catheter-directed aspiration. A covered stent (Passager) was used in cases of dilation-induced rupture not controlled by balloon tamponade. RESULTS: An underlying stenosis was diagnosed in 100% of cases. Half of them were located in the anastomotic area. The initial success rate of interventional radiology was 97%. Dilation-induced rupture occurred in nine cases (13%) but stents were necessary in only two cases. The rate of significant clinical complications was 2.8% (bacteraemia, pseudoaneurysm). Primary and secondary patency rates at 1 year were 39 and 79%, respectively. CONCLUSIONS: Delayed maturation of native fistulas should lead systematically to imaging as an underlying stenosis is diagnosed in all cases. Interventional radiology can treat the majority of cases and achieve a 97% success rate but early recurrence of stenoses can occur. Multidisciplinary re-evaluation of the patient must, therefore, be performed after radiological salvage of the fistula.

Adult↗
PubMed2001

Increased glomerular cell heparan sulfates in vitro by ciclosporin A: a Possible explanation of Its beneficial effect in idiopathic nephrotic syndrome.

BACKGROUND/AIM: In idiopathic nephrotic syndrome (INS), ciclosporin A (CsA) was shown to decrease proteinuria, an effect explained by its immunologic and hemodynamic actions. In order to determine whether CsA could have a direct action on glomerular cells, we studied the effect of CsA on glomerular cells in vitro, particularly on glycosaminoglcycans (GAG) and heparan sulfates (HS) which are decreased in INS patients. METHODS: Human glomerular epithelial cells and rat mesangial cells were cultured at various concentrations of CsA. HS were quantified using a cationic membrane after metabolic labeling. RESULTS: Mesangial cell GAG and HS and epithelial cell HS increased significantly when cells were cultured with CsA. For both cell types this increase was prevailing on the secreted fraction of HS in comparison with the cellular fraction. CsA induced also an increase in cellular cAMP levels, but the effect of CsA was not transduced via a cAMP pathway. CONCLUSIONS: CsA is able to increase glomerular GAG and HS in vitro. As this effect of CsA was the opposite effect on glomerular cells to the effect of plasma from INS patients, we conclude that this direct action of CsA on glomerular cells could explain in part the effect of this drug in decreasing proteinuria in INS.

Animals↗
PubMed2000

Role of cyclic AMP in idiopathic nephrotic syndrome: a pathway involving a decrease in glomerular cell heparan sulfates?

The physiopathological mechanisms of idiopathic nephrotic syndrome involve a circulating plasma factor and a decrease in HS in the glomerular basement membrane. Previous studies have demonstrated that plasma from patients with INS decreases glomerular cell HS in vitro. We examined the involvement of cyclic adenosine monophosphate (cAMP) in this interaction. We studied the effect of plasma from patients with INS on mesangial cell cAMP. We also determined mesangial cell HS when cAMP levels were modified using a cationic membrane after metabolic labeling. Cellular cAMP levels increased significantly when mesangial cells were incubated with plasma from patients with INS in comparison with control plasma (+77%, P = 0.01). Forskolin and IBMX, which increased cellular cAMP, decreased HS levels (-21 +/- 9% and -15 +/- 6% respectively, P < 0.05 for both), whereas dideoxyadenosine, which decreased cellular cAMP, increased HS levels (+24 +/- 7%, P < 0.05). Plasma from patients with INS decreased glomerular cell HS in comparison with control plasma (-34 +/- 8%, P < 0,05). This effect was abolished when cells were preincubated with ddAdo to prevent an increase in cAMP levels. We conclude that in mesangial cells, plasma from patients with INS increases cAMP levels, and that cAMP mediates a decrease in HS levels. Moreover, the action of plasma from patients on HS was inhibited when an increase in cAMP was prevented. cAMP may therefore be instrumental in the negative effect of the plasma factor on mesangial cell HS.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Transplant renal artery stenosis: potential role of ischemia/reperfusion injury and long-term outcome following angioplasty.

PURPOSE: We assess long-term arterial pressure, renal function, and patient and graft survival in recipients of cadaveric kidney transplant with or without transplant renal artery stenosis. We also evaluate the risk factors for transplant renal artery stenosis. MATERIALS AND METHODS: We reviewed and analyzed baseline clinical, immunological and outcome data for 26 patients with transplant renal artery stenosis before and after angioplasty, and 72 without stenosis on angiography. We also analyzed graft and patient survival in 304 cases in which angiography was not performed. RESULTS: The incidence of transplant renal artery stenosis was 6.6% (26 of 402 patients). Acute rejection episodes (42 versus 22%, p <0.05) and delayed graft function (50 versus 32%, p <0.10) were more frequent, and mean cold ischemia time plus or minus standard error (29.2+/-1.7 versus 24.8+/-1.3 hours, p <0.01) was longer in patients with than without transplant renal artery stenosis. The technical success of angioplasty was 92.3%. Restenosis was documented in 6 of 26 patients (23.1%). Revascularization resulted in a decrease in arterial pressure and better renal function. The 8-year patient (100, 98.6 and 95.7%, respectively) and graft (88.1, 88.9 and 89.3%, respectively) actuarial survival rates were similar among patients with or without transplant renal artery stenosis, and those who did not undergo angiography. CONCLUSIONS: Transplant renal artery stenosis had no detectable influence on long-term arterial pressure control, renal function, and patient and graft survival rates, which were similar to those in patients without stenosis. Long cold ischemia time may have a role in the development of transplant renal artery stenosis through ischemia/reperfusion injury.

Adult↗
PubMed1998

[Transplant renal artery stenosis: long term effect of angioplasty on arterial pressure control and renal function].

We assessed the long-term (M +/- SE: 68 +/- 3 months) arterial pressure and renal function of cadaveric kidney transplant recipients with and without significant (> 70% diameter reduction) transplant renal artery stenosis (TRAS) at angiography. Baseline clinical, immunological and outcome data for 26 patients with TRAS (incidence of TRAS: 6.6%) before and following angioplasty and 72 patients without stenosis at angiography were reviewed and analyzed. The 2 groups were similar with respect to recipient sex ratio and age (45 vs 46), duration of transplantation (7 months), cause of renal failure, donor sex and age, HLA-antigen mismatches and titers of anti-HLA antibodies, CMV infection and anti-CMV antibodies in donors and recipients. The technical success of angioplasty was 92.3%. Restenosis was documented in 6/26 patients (23.1%). Revascularization resulted in a decrease of arterial pressure and number of antihypertensive medications and a lower serum creatinine compared to baseline values. The long-term arterial pressure and serum creatinine levels were similar in patients with and without stenosis. In conclusion, TRAS after revascularization had no detectable influence on the long-term arterial pressure control and renal function within a follow-up period of 68 +/- 3 months.

Angioplasty↗
PubMed1995

[Lymphocyte adhesion of human peripheral blood to aortic endothelial cells of a porcine xenograft: preferential adhesion to NK CD3-CD16+ cells].

Xenotransplantation, the transplantation of tissues or organs between species find renewal interest because of human organ shortage. As the xenogeneic transplantation leads immediately to an humoral mediated rejection with graft necrosis, the study of the cellular response is not possible in vivo. So we developed an in vitro model to study the adhesion of human peripheral blood lymphocytes (PBL) to porcine aortic endothelial cells (PAEC). We showed that PBL were able to bind to PAEC, and that this adhesion was increased when PAEC were stimulated with human recombinant TNF-alpha. The action of TNF-alpha is maximal when PAEC were stimulated during 6 hours with 100 U/ml TNF-alpha. This adhesion involved preferentially CD3-CD16+ NK cells compared with CD3+CD16- T lymphocytes. Finally monoclonal antibodies directed against PBL adhesion molecules decreased PBL adhesion to PAEC. PBL adhesion to PAEC would be a first step in a cellular mediated rejection in xenotransplantation.

Animals↗
PubMed1993

Insufficient dialysis shunts: improved long-term patency rates with close hemodynamic monitoring, repeated percutaneous balloon angioplasty, and stent placement.

Over 54 months, 70 short stenoses of 63 shunts (32 Brescia-Cimino fistulas, 31 grafts) in 59 patients necessitated a first percutaneous transluminal angioplasty (PTA). Restenosis led to 63 redilations in 38 lesions. Nine stents were inserted in seven grafts and two proximal veins in seven patients, the indication being that stenosis had recurred twice in 6 months. In three of these stenoses, five delayed intrastent redilations were necessary. Three previously dilated occluded grafts were recovered with local thrombolysis. Morbidity was 4.08%, with one immediate rupture, four delayed pseudoaneurysms (1-28 months), and two periprocedural bacteremias. Half (15 of 29) of graft stenoses and only 14% (four of 27) of Brescia-Cimino fistula stenoses had a mean restenosis interval of less than 6 months. The mean restenosis interval increased from 3.6 months +/- 0.5 (standard deviation) before stent placement to 15.2 months +/- 0.4 after stent placement (P < .001). Insertion of a stent can be advised when stenoses of graft venous anastomoses have recurred twice in less than 6 months. The combination of all interventional radiologic procedures allowed a significant improvement in secondary patency rates after PTA, with 82% at 1 year, 79% at 2 years, and 71% at 3 years.

Adult↗