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Biomedical subjects

C Tielemans

Publications and source records attributed to C Tielemans.

At least 19 recordsLinked to original sources
PubMed2004

Lipid and apoprotein changes during atorvastatin up-titration in hemodialysis patients with hypercholesterolemia: a placebo-controlled study.

BACKGROUND: Patients with end-stage renal disease commonly present with an atherogenic lipid profile characterized by the accumulation of triglyceride-rich, apoprotein B-containing "remnant" lipoproteins, small dense low-density lipoprotein, and low levels of high-density lipoprotein. They are at increased cardiovascular risk and may benefit from drastic lipid-lowering treatment with atorvastatin, a potent, broadacting lipid regulator. This study aims to assess the effects of atorvastatin on the lipid profile in hemodialysis patients, to determine wether atorvastatin is also effective at lowering lipid levels in this particular high-risk subgroup. METHODS: In this randomized, placebo-controlled, double-blind study in hemodialysis patients with hypercholesterolemia (n = 42, mean total cholesterol 243 +/- 33 mg/dl (6.3 +/- 0.8 mmol/l)), the efficacy of 4-weekly increasing doses of atorvastatin (10 - 40 mg daily) was investigated. Lipids and apoproteins were measured in plasma and isolated lipoprotein fractions. RESULTS: Mean total cholesterol and low-density lipoprotein cholesterol progressively decreased with increasing doses of atorvastatin (total cholesterol -33%, low-density lipoprotein cholesterol -43% after 12 weeks), while high-density lipoprotein cholesterol remained unchanged. Plasma levels of apoprotein B and apoprotein E were also significantly reduced by atorvastatin 10 mg, while up-titration to 20 and 40 mg daily provided additional benefits by lowering triglycerides and apoprotein C-III. At week 12, the fraction of small dense low-density lipoprotein was significantly reduced from 23% - 18%, and apoprotein B-containing intermediate-density lipoproteins were no longer detectable. CONCLUSION: In conclusion, atorvastatin not only treated hypercholesterolemia but also favorably affected the uremic lipid profile in patients on hemodialysis. Atorvastatin 4-weekly dose escalation up to 40 mg daily was well-tolerated. Further prospective studies are needed to evaluate the impact of this improved lipid profile on morbidity and mortality.

Aged↗
PubMed2002

[The medico-surgical department of nephrology dialysis and renal transplantation].

The Department of Nephrology of the Hospital Erasme, opened 25 years ago, is now performing, each year, 22,000 hemodialysis sessions, 800 patient-weeks of peritoneal dialysis treatment and 70 renal grafts. Scientific contributions of the department deal with vascular access for hemodialysis, susceptibility to infections of dialyzed patients, parathyroid surgery, biocompatibility of dialysis membranes, predictive factors of renal graft survival, immunosuppression with monoclonal antibodies, experimental studies of graft tolerance and rejection, toxic nephropathies. The most original contributions are related to anaphylactoïd reactions in hemodialysis by association of acrylonitrile membranes with inhibition of the converting enzyme, to advantages and side effects of OKT3 monoclonal antibody and to discovery and study of the Chinese herbs nephropathy.

Belgium↗
PubMed2000

Long-term results of subcutaneous parathyroid grafts in uremic patients.

HYPOTHESIS: Parathyroid glands are normally surrounded (entirely or partially) by fatty tissue. Subcutaneous parathyroid grafts are thus located in a normal environment. Therefore, we postulated that the late results of subcutaneous implantation of parathyroid tissue in uremic patients should be at least as good as those reported for intramuscular grafting. We also challenged the idea that the recurrence rate of renal hyperparathyroidism after surgery depended solely on the type of hyperplasia (diffuse vs nodular) observed in the implanted tissue. DESIGN: A retrospective study of a series of patients without loss to follow-up. SETTING: A university hospital and 9 affiliated dialysis units. PATIENTS AND INTERVENTIONS: Fifty-nine patients (33 women and 26 men) operated on for renal hyperparathyroidism underwent the resection of at least 4 parathyroid glands followed by presternal subcutaneous implantation of parathyroid tissue. They were followed up for 12 to 130 months (median, 38 months). MAIN OUTCOME MEASURES: Failure of treatment, recurrence of disease, and hypoparathyroidism. RESULTS: During the study period, 9 patients had to undergo another operation: 2 (3%) for persistent hyperparathyroidism due to a fifth ectopic gland and 7 (12%) for recurrence of hyperparathyroidism resulting from hypertrophy of the subcutaneous grafts. Four patients received a kidney transplant. The prevalence of hypoparathyroidism (intact parathyroid hormone serum level <1.6 pmol/L with a normal or low serum calcium concentration) was 14% (8 of 59 patients), and the curve representing the distribution of intact parathyroid hormone serum concentrations among operated on patients was shifted to the left when compared with the curve of patients who underwent hemodialysis and who had no indication for parathyroid surgery. In this latter group, the peak of the curve was situated between 1 and 2 times the upper normal limit, while it was in the normal range 12 to 130 months after total parathyroidectomy and subcutaneous parathyroid autotransplantation. No relation was observed between the recurrence rate of the disease and the histological characteristics of the parathyroid grafts. Also, their function was not influenced by the presence or absence of aluminum deposits in bone biopsy specimens that were obtained at the time of cervical exploration. CONCLUSIONS: The late results of total parathyroidectomy and presternal subcutaneous grafting compare favorably with the published data on other surgical techniques proposed for the treatment of renal hyperparathyroidism. The ease with which the hypertrophied grafts are removed when the disease recurs warrants further use of this procedure.

Female↗
PubMed2000

Role of complement and platelet-activating factor in the stimulation of phagocytosis and reactive oxygen species production during haemodialysis.

BACKGROUND: Neutrophil phagocytic functions have been studied extensively in haemodialysis (HD) patients; however, results are contradictory and the mechanisms that modulate phagocytosis and oxidative burst during dialysis are not completely understood. METHODS: The present study investigated neutrophil functions in a selected population of patients before and during clinical dialysis with cuprophane, and polyacrylonitrile (AN69) membranes. We measured phagocytosis of Escherichia coli and intracellular hydrogen peroxide (H2O2) production by flow cytometry in whole blood. RESULTS: Before dialysis, neutrophils from HD patients showed normal phagocytic capability and H2O2 formation. Phagocytosis of FITC-E. coli was significantly stimulated in cuprophane but not AN69-treated patients. Spontaneous and stimulated H2O2 production was enhanced with both cuprophane and AN69 membranes. We then investigated in vitro the role of complement and platelet-activating factor (PAF) in the activation of neutrophils. Incubation of whole blood with C5a increased phagocytosis but not H2O2 production. On the contrary, the addition of synthetic PAF showed a markedly stimulated H2O2 production without increase in phagocytosis. Moreover, during dialysis with formaldehyde-reused cuprophane, complement activation was abolished and phagocytosis was no longer enhanced, while the stimulation of H2O2 production persisted. In addition, we also excluded a particular role of the membrane itself in the activation of neutrophils. CONCLUSION: We demonstrated that in a selected population of HD patients, neutrophils exhibit normal phagocytic capability and normal intracellular H2O2 production. During dialysis, the stimulation of phagocytosis observed with cuprophane is complement dependent, whereas the enhanced H2O2 production observed with both cuprophane and AN69 membranes might be related to PAF production.

Complement Activation↗
PubMed2000

Fibrate-induced increase in blood urea and creatinine: is gemfibrozil the only innocuous agent?

BACKGROUND: Some reports indicate that fibrates can induce renal dysfunction. However, the clinical characteristics of these episodes, and the respective nephrotoxicity of the four main fibrates used-namely, fenofibrate, bezafibrate, ciprofibrate, and gemfibrozil-remain ill defined. METHODS: To better characterize this side-effect, we first reviewed the charts of 27 patients from our institution who developed an impairment of renal function during fibrate therapy. We next analysed the articles (n=24) that contained data on renal function in patients taking fibrates (n=2676). RESULTS: Among our 27 patients, 25 were on fenofibrate therapy, one was taking bezafibrate, and one ciprofibrate. Nineteen were recipients of solid-organ transplants (kidney recipients, n=15; heart or heart-lung recipients, n=4), and eight were non-transplanted patients with some impairment of renal function. Baseline plasma creatinine ranged from 0.9 to 2.9 mg/dl. It increased by a mean of 40% after the start of fibrate therapy. There was a concomitant increase of blood urea values (mean 36%) in most of the patients. Renal function returned to baseline in 18/24 patients after fibrate discontinuation. However, six patients, all transplant recipients, experienced a permanent increase in plasma creatinine. The incidence of fibrate-induced renal dysfunction among our series of kidney transplant recipients was 60%, as it occurred in 15 of the 25 patients who had ever taken fibrates. An increase of mean creatinine values during therapy was described in all papers on fenofibrate (n=7) and bezafibrate (n=8) (range 8-18% and 8-40% respectively), and in three of four papers dealing with ciprofibrate (range 6-16%). No significant renal impairment was described in any of the eight articles reporting data on gemfibrozil therapy. CONCLUSION: Therapy with fenofibrate, bezafibrate, and ciprofibrate may induce renal dysfunction. Gemfibrozil appears to be devoid of this side-effect.

Bezafibrate↗
PubMed2000

Comparison of cellulose diacetate and polysulfone membranes in the outcome of acute renal failure. A prospective randomized study.

BACKGROUND: Whether the nature of haemodialysis (HD) membranes can influence the outcome of acute renal failure (ARF) remains debatable. Recent studies have suggested that dialysis with bioincompatible unsubstituted cellulosic membranes is associated with a less favourable patient outcome than dialysis with biocompatible synthetic membranes. Since we generally use a modified cellulosic membrane with substantially lower complement- and leukocyte-activating potential than cuprophane, for dialysis of patients with ARF, and because there are no data in the literature regarding the influence of modified cellulosic membranes on the outcome of patients with ARF, we compared the outcome of ARF patients dialysed either with cellulose diacetate or with a synthetic polysulfone membrane. We also investigated the potential role of permeability by comparing membranes with high-flux versus low-flux characteristics. METHODS: This prospective, randomized, single centre study included 159 patients with ARF requiring HD. Patients were stratified according to age, gender, and APACHE II score and then randomized in chronological order to one of three dialysis membranes: low-flux polysulfone, high-flux polysulfone and meltspun cellulose diacetate. RESULTS: Aetiologies of ARF and the prevalence of oliguria were similarly distributed among the three groups. There was no significant difference between the three groups for survival (multivariate Cox's proportional hazards model, P=0.57), time necessary to recover renal function (P=0.82), and number of dialysis sessions required before recovery (P=0.86). Multivariate analysis showed that survival was significantly influenced only by the severity of the disease state (APACHE III score, P<0.0001), but not by the nature of the dialysis membrane (P=0.57) or the presence of oliguria (P=0.24). CONCLUSIONS: Among patients with ARF requiring HD survival and recovery time are not significantly influenced by the use of either meltspun cellulose diacetate or the more biocompatible high-flux or low-flux polysulfone. Dialysis using modified cellulose membranes is just as effective as dialysis using synthetic polysulfone membranes, but at a lower cost. In addition, the flux of the membrane did not influence patient outcome.

Acute Kidney Injury↗
PubMed2000

Effect of regional citrate anticoagulation on leukopenia, complement activation, and expression of leukocyte surface molecules during hemodialysis with unmodified cellulose membranes.

BACKGROUND: Dialysis with complement-activating membranes is associated with leukopenia, which is related to an increased expression of adhesion molecules on leukocytes. Citrate chelates calcium and has been claimed to attenuate leukopenia. METHODS: In this study, the effects of citrate anticoagulation on leukocyte and granulocyte counts, complement activation, and the expression of CD11b, CD11c, and CD45 on the surface of granulocytes were evaluated during hemodialysis with unmodified cellulose membranes. Standard heparin was compared to citrate in three different schedules: citrate was infused to obtain a concentration of either 7 or 10 mmol/l blood. CaCl(2) was administered into the dialyzer outlet at 8. 25 mmol Ca(2+)/h (citrate 10 mmol/l) or at 11 mmol Ca(2+)/h (citrate 7 and 10 mmol/l) to reconstitute the calcium levels in the blood returning to the patient. RESULTS: The use of citrate at a high concentration (10 mmol/l) was associated with a blunted upregulation of CD11b, both at the inlet and at the outlet bloodline; for CD11c a reduced upregulation was observed on granulocytes harvested from the inlet bloodline. No effects of citrate were observed on leukopenia, granulocytopenia, or complement activation. A positive correlation between the decrease in systemic ionized Ca(2+) concentration and the increase in CD11b and CD11c expression was found. CONCLUSION: Citrate/CaCl(2) administration affects leukocyte adhesion molecule expression in a dose-dependent way; however, no significant effect could be demonstrated on leukopenia and complement activation.

Adult↗
PubMed1999

Efficacy of oral immunotherapy on respiratory infections in hemodialysis patients: a double-blind, placebo-controlled study.

BACKGROUND: Hemodialysis (HD) patients suffer from several immune defects that make them prone to develop bacterial infections, in particular respiratory tract infections (RTIs). PATIENTS AND METHODS: As previous studies have shown that oral immunotherapy with an immunomodulating bacterial extract (IBE) is effective against RTIs, we decided to test its efficacy and safety in HD patients during a double-blind placebo-controlled prospective study. 40 HD patients with a documented history of RTIs in the previous year were treated for 24 weeks of the endemic season with one capsule daily of IBE (n = 21) or placebo (PL, n = 19). Clinical examinations, measurements of Mac-1 and gp150.95 on circulating phagocytes and routine laboratory evaluations were performed at week 0, 4, 12 and 24. Patients were also examined at each dialysis session allowing an accurate recording of any infectious episode, its treatment and of any untoward effect. RESULTS: During the last period of the study (weeks 13-24), IBE significantly reduced the number of patients with RTIs and consequently of antibiotic treatment courses as compared to PL (p = 0.018), whereas no difference was detected between IBE and PL during periods I (weeks 0-4) and II (weeks 5-12). There was no difference between IBE and PL for other, non respiratory infections. IBE was associated at several time points with an increased expression on phagocytes of adhesion molecules involved in phagocytosis (Mac-1 and gp150.95). However, the expression of these molecules was not predictive for the occurrence of RTI. IBE was on the whole as well tolerated as PL, 7 patients presented side effects (5 IBE, 2 PL, NS) which led to drop-out in 4 cases (3 IBE, 1 PL). No serious side effect was recorded, gastrointestinal upset being the most prevalent type. CONCLUSION: The results of this study indicate that immunomodulation with selected bacterial extracts constitutes a promising approach for the prevention of bacterial airway infections in groups at risk, such as HD patients.

Adjuvants, Immunologic↗
PubMed1998

Evaluation of surgical treatment of renal hyperparathyroidism by measuring intact parathormone blood levels on first postoperative day.

Intact parathormone (inPTH) has a short half-life. Its blood level on the first day after total parathyroidectomy and subcutaneous parathyroid implantation (PTX + G) should therefore allow an early diagnosis of missed residual parathyroid tissue. We tested this hypothesis in 72 uremic patients who were followed for 6 to 110 months after operation. Nine were reoperated for recurrence of the disease. Graft removal was successful in four patients who had post-PTX inPTH levels of 16 pg/ml or lower. In five patients, an overlooked parathyroid gland had to be resected. All of them had elevated post-PTX inPTH blood levels ranging from 72 to 791 pg/ml (upper normal limit 55 pg/ml). Three of these patients had presented with hypocalcemia after PTX. We conclude that the inPTH blood concentration on the first day after PTX allows more precise evaluation of the efficacy of the surgical procedure than the postoperative evolution of blood calcium levels. It is also useful for localizing the source of excessive PTH secretion (graft or overlooked gland) when the disease recurs.

Female↗
PubMed1998

[Does the biocompatibility of the hemodialysis membrane influence the prognosis of acute renal insufficiency?].

Several recent publications have suggested that the use of cuprophane in the setting of acute renal failure is associated with a higher mortality (especially from sepsis) and a slower recovery of renal function in the survivors in comparison with more biocompatible membranes. We present here a critical review of these publications and point to several methodological bias that might invalidate their conclusions. However, while waiting further information, we would advocate to abandon the use of cuprophane to dialyze patients with acute renal failure.

Acute Kidney Injury↗
PubMed1996

Effects of steroids on the progression of renal failure in chronic interstitial renal fibrosis: a pilot study in Chinese herbs nephropathy.

Chinese herbs nephropathy is characterized by an extensive interstitial fibrosis and by a rapid evolution to end-stage renal failure. We thus decided to try steroid therapy (prednisolone 1 mg/kg for 1 month, tapered off 0.1 mg/kg every 2 weeks) in cases with moderate renal failure and evidence of deterioration in renal function. Our steroid group (SG) consisted of 12 female patients with biopsy-proven renal fibrosis who were followed for at least 12 months after the initiation of steroids. Plasma creatinine level (Pcreat) ranged from 1.8 to 3.9 mg/dL (mean +/- SEM, 2.8 +/- 0.2 mg/dL) when steroids were initiated at t = 0. Renal failure was in progression since Pcreat was 2.1 +/- 0.1 mg/dL (P = 0.022) 3 months before t = 0. Our control group (CG; N = 23) was selected retrospectively from among the 81 patients in the Belgian Register of Chinese Herbs Nephropathy. Compared with the CG, renal function was better preserved in the SG (Pcreat; mean +/- SEM): SG v CG, 2.9 +/- 0.3 mg/dL v 5.3 +/- 0.5 mg/dL at 6 months (P = 0.0024) and 4.0 +/- 0.7 mg/dL v 7.1 +/- 0.5 mg/dL at 1 year (P = 0.001). The slope of the reciprocal serum creatinine concentration was similar in both groups before t = 0 (-0.0463 mg/dL/mo in the SG v -0.0438 mg/dL/mo in the CG; P = 0.83), but it became less steep after initiation of steroid therapy (between 0 and 6 months, -0.000742 mg/dL/mo in the SG v -0.0284 mg/dL/mo in the CG; P < 0.001). Finally, only two of the 12 patients in the SG required dialysis at 1 year compared with 16 of the 23 patients in the CG (P = 0.0045). We conclude that steroid therapy slows the progression of renal failure in a disease characterized by an interstitial fibrosis that progresses quickly despite the fact that the insulting agent has been withdrawn. This supports the hypothesis that renal interstitial fibrosis may be an immune-mediated process.

Aristolochic Acids↗
PubMed1996

Effects of ultrapure and non-sterile dialysate on the inflammatory response during in vitro hemodialysis.

Several studies support the hypothesis that bacterial contamination of the dialysate stimulates the inflammatory response to hemodialysis (HD) and increases the long-term morbidity of HD patients; this phenomenon could also be modulated by the nature of the HD membrane. Therefore, this study was designed to compare the effects of non-sterile (NSBD, mean endotoxin content +/- SEM 97 +/- 22 EU/ml) and ultrapure bicarbonate dialysate (UPBD, sterile and pyrogen-free, obtained by ultrafiltration through polyamide) on several aspects of the inflammatory reaction during in vitro HD. The HD sessions (7 in each experimental group) were performed using miniaturized new cuprophane (CU) and polyacrylonitrile (PAN) hollow fiber dialyzers, and closed dialysate and blood circuits (the latter filled with heparinized blood from healthy donors). Plasma C3aDesarg levels were significantly increased after 15 minutes (t1) and increased further after three hours (t2) of CU HD, while during PAN dialysis they decreased from t0 to t1 and t2; however, no difference appeared between experiments with NSBD and UPBD. Granulocyte (PMN) and monocyte (MNC) expression of LFA-1, Mac-1, and CD45 at the start (t0), t1 and t2 was quantitated by flow cytometry analysis, after staining of the cells with specific fluorescinated monoclonal antibodies. In contrast with published data of in vivo HD, LFA-1 was overexpressed at t1 and peaked at t2, which suggests that the leukocytes expressing more LFA-1 leave the systemic circulation during in vivo HD. During CU HD, Mac-1 and CD45 on PMN and MNC were significantly increased at t1, and still more at t2. During PAN HD, Mac-1 and CD45 remained unchanged at t1, but increased significantly at t2 on PMN as on MNC. Again, no significant difference was found between NSBD and UPBD in LFA-1, Mac-1 and CD45 expression on PMN and MNC, during both CU and PAN HD. AFter three hours of dialysis, plasma levels of TNF-alpha, but not of IL-6, were significantly increased with CU and PAN. Again, no difference appeared when NSBD and UPBD were compared. Moreover, the lack of influence of bacterial contamination of the dialysate on TNF-alpha production was confirmed when MNC were cultured up to 24 hours after the end of the HD session. We conclude that complement activation products, either in plasma (CU) of those adsorbed on the HD membrane (CU and PAN) play the major role in the overexpression of beta 2-integrins and CD45 by PMN and MNC during HD. Also, bacterial products (at the levels that can be found in clinical conditions) do not influence either beta 2-integrin overexpression or TNF-alpha production induced by the dialysis membrane.

Adult↗
PubMed1996

Cuprophane haemodialysis induces upregulation of LPS receptor (CD14) on monocytes: role of complement activation.

BACKGROUND: The CD14 molecule is a high-affinity receptor for the complex formed by lipopolysaccharide (LPS) and LPS-binding protein. METHODS: We examined by flow cytometry the effect of in vitro and in vivo haemodialysis on cuprophane membrane and recombinant C5a on the expression of CD14 molecules at the surface on monocytes. Monocyte CD14 expression was also studied during in vitro and in vivo haemodialysis on polyacrylonitrile AN69 membrane. RESULTS: In vitro haemodialysis of whole blood from healthy volunteers on cuprophane membrane resulted within 30 min in upregulation of monocyte CD14 expression. The reuse of the cuprophane membrane abolished both complement activation and CD14 upregulation. Moreover, incubation of whole blood with recombinant C5a led to an increased monocyte CD14 expression supporting a role for complement activation in the rapid cuprophane-induced CD14 upregulation. During AN69 dialysis which is not associated with complement activation in the blood phase, monocyte CD14 expression did not change during the first 60 min but was significantly increased after 3 h of in vitro haemodialysis. This late increase might be related to the presence of complement activation products adsorbed on the membrane. In vivo dialysis on cuprophane membrane also resulted in early monocyte CD14 upregulation as indicated by higher CD14 expression found after 60 min on monocytes obtained from the efferent as compared to the afferent line of the dialyser, a phenomenon that was not observed during haemodialysis on AN69 membrane. CONCLUSION: Haemodialysis on the complement-activating cuprophane membrane induces the rapid upregulation of the CD14 LPS-receptor on monocytes.

Acrylic Resins↗
PubMed1995

[Investigation plan for acute kidney failure].

Acute renal failure often has a complex origin, especially in critically ill patient. Moreover, the tools for investigation of renal failure are generally unspecific, so that the work-up must be based on several elements. It is particularly important to differentiate failure of the kidney itself from prerenal or postrenal failure, since the therapeutic implications are very different. We propose to base the investigation of acute renal failure on some elements to be evaluated in a rapid succession. The complete evaluation should also take into account the consequences of renal failure, which also have therapeutic implications.

Acute Kidney Injury↗