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Biomedical subjects

C Mion

Publications and source records attributed to C Mion.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Amanita proxima poisoning: a new cause of acute renal insufficiency].

To our knowledge Amanita proxima poisoning has never been reported. Amanita proxima is a mushroom seldomy encountered, similar to a common and edible species: Amanita ovoïdae. During October 1992, we had the opportunity to care for five cases of intoxications with Amanita proxima. In all cases early digestive disorders, cytolytic hepatitis and acute renal failure were noted. Outcome was favourable for all patients within three weeks with total recovery of both renal and hepatic functions with symptomatic treatment. Temporary dialysis was required in four patients.

Acute Kidney Injury↗
PubMed1994

Dialysis solutions buffered with lactate or bicarbonate: in vitro comparison of two dialysis solutions on human peritoneal cell growth from ESRD and non-ESRD patients.

In order to evaluate the injury to the mesothelial cell layer during long-term peritoneal dialysis (PD), a dialysis solution (solution A), buffered with bicarbonate, stabilized with 10 mmol/L glycylglycine, and sterilized by filtration (0.22 micron double filtration, pH = 7.4), was compared to traditional heat sterilized lactate solution (solution B) on human mesothelial cell cultures. The respective effects of both solutions were evaluated on first passage cells by 3H thymidine incorporation after 72-, 96-, 120-, and 144-h contact. Mesothelial cells to be cultured were obtained from the omentum biopsies of 7 end-stage renal disease (ESRD) patients (during first peritoneal catheter placement) and from 7 non-ESRD patients undergoing abdominal surgery. Solution A (diluted 1/5) induced a time-dependent stimulation of growth in 6 cases of ESRD patient cell cultures, and inhibition occurred only in 1 case. Stimulation was also observed in 5 non-ESRD patient cell cultures, and no effect occurred in 2 cases. Solution B inhibited growth in all the cultures except in 1 case of an ESRD patient in which no effect was observed. This study shows that solution A induced mesothelial cell proliferation, while an inhibitory effect of solution B was observed. No significant differences were observed between the sensitivity of mesothelial cells from ESRD and non-ESRD patients. Further analysis will be carried out to identify precisely the cause of the differences observed: buffer or glycylglycine by themselves and/or glucose by-products.

Aged↗
PubMed1994

[Temporary vascular access: from peripheral to central, from temporary to permanent].

Temporary vascular access (TVA) is a basic requirement in clinical nephrology. TVA permits immediate and repeated hemodialysis for all type of ESRD patient. Going from peripheral to central and from temporary to permanent angioaccess are the two main trends observed in TVA in contemporary dialysis. Our experience over the last decade illustrates this TVA changes. On the one hand peripheral arterio-venous shunt has been forsaken in favour of percutaneous implanted central venous catheters. On the other hand, two types of central venous catheters have been used covering up our preferences: catheters for short term use (< 7 days) usually via femoral vein and catheters for long term use (7 days to months) mainly via the internal jugular vein. Due to traumatic and/or long term mechanical risks (venous stenosis and/or thrombosis), the subclavian way has been abandoned in our unit. Performances (blood flow rate 250-350 ml/min, recirculation rate 9-12%) obtained in about 1500 patients warranted dialysis efficiency. Traumatic and/or mechanic lesions were the most frequent complications observed with the femoral catheter, while infection remained the most important one associated with the long term use of jugular vein catheters. Therefore, it is clear that over the last decade temporary vascular access was becoming synonymous with percutaneous central venous catheter. Such an approach has greatly simplified the task of physicians while facilitating the management of large uremia treatment program.

Adult↗
PubMed1994

Enhancement of reactive oxygen species production and cell surface markers expression due to haemodialysis.

Leukocyte activation during haemodialysis (HD) was evaluated by reactive oxygen species (ROS) production and cell surface markers expression (CD11b: C3bi receptor and CD25: IL2 receptor). Eight end-stage renal disease patients were exposed to three dialysis phases according to a A/B/A protocol study. During phase A polysulphone (PS) membranes were used and during phase B cuprophane (CU) membranes were used. Each phase lasted 3 weeks. Timed samples were collected during the last session of each phase at 0, 15, and 30 min of HD. Flow cytometry analysis was performed both on monocytes (MO), polymorphonuclears (PMN), and lymphocytes (Ly). Hydroethydine was used as a marker of cell-ROS production. Specific monoclonal antibodies were used to analyse the cell surface markers. CU increased ROS production in PMN and MO by 10- and 2.4-fold respectively and had no significant effect on Ly. CU enhanced 16-fold CD11b expression on PMN, and increased also CD11b and CD25 expression on MO by 7- and 40-fold respectively. On the contrary, PS did not affect either ROS production or cell surface markers expression in MO, PMN, Ly. We conclude that oxydative metabolism and cell surface markers expression of PMN and MO were significantly increased with cuprophane membranes and not with polysulphone membranes, suggesting that complex cell-cell interactions were involved in membrane-related bioincompatibility phenomena.

Aged↗
PubMed1993

Calcium kinetics and the long-term effects of lowering dialysate calcium concentration.

The optimal dialysate calcium (Ca) content for hemodialysis has been classically fixed at 1.75 mM. However, this dialysate Ca concentration (dCa) with its positive intradialytic Ca balance combined with the use of CaCO3 as a phosphate binder may result in hypercalcemia. To prevent or treat hypercalcemia, a decrease in dCa has been proposed. In the present study both the acute and the long-term effects of lowering dCa were assessed. Additionally, given the results obtained after one year with low dCa the effectiveness of i.v. 1 alpha vitamin D3 in lowering PTH serum levels in two groups of patients dialyzed with different dCa was also studied. (a) Ca kinetics during hemodialysis (HD) and on line hemodiafiltration (HDF) were studied in a group of nine stable patients who were sequentially treated with 1.75, 1.5 and 1.25 mM dCa. Dialysate was the same but for the dCa which was lowered stepwise. Na, K, tCa, ionized Ca (iCa), proteins, phosphate and pH were measured from blood inlet and outlet and dialysate outlet at the start, one hour, two hours and after the treatments. At the same time weight, blood pressure and heart rate were recorded. The sieving of iCa was significantly different in HDF versus HD (F = 6.73; P < 0.01); intravenous infusion of 18 liters of filtered ultrapure dialysate compensated the Ca loss due to the convective component of HDF, as iCa was similar at the blood inlet in HD and HDF in the three dCa tested (F = 2.59; NS). Intradialytic iCa kinetics measured in the blood inlet were significantly different with different dCa (P < 0.001 for 1.75 mM vs. 1.5 mm and P < 0.001 for 1.5 mM vs. 1.25 mM). A significant increase in post-dialysis iCa was observed with dCa of 1.75 and 1.5 while no modification was observed with 1.25 mM dCa. (b) Regarding long-term effects of lowering dCa, seven of the nine patients acutely studied were followed for a one year period after changing from dCa = 1.5 to dCa = 1.25 mM. A control group of six patients was maintained with dCa = 1.5 for the same period of time and with the same treatment schedule but for dCa. Total Ca, phosphate and alkaline phosphatase were assessed monthly, and phosphate binders and oral vitamin D derivative doses were adapted accordingly. Intact PTH was determined quarterly. CaCO3 oral intake was more than doubled in the low dCa group. Total Ca, phosphate and ALP were similar in both groups over the assessed year.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

[Recombinant human erythropoietin in uremic patients in substitute treatment].

The recent availability of Recombinant Human Erythropoietin (EPO) has radically stirred-up diagnosis and therapeutical approach of anemia in dialysis patients. By correcting anemia in a dose related manner in virtually all dialysis patients, clinical use of EPO has confirmed its remarkable efficiency. Correction of anemia marked by a rapid improvement in "well being" of patients is also objectively associated with the correction of most of the debilatating multiple organs dysfunction due to the uremic state. Hypertension is one of the more frequent and worrying complication associated with EPO therapy. Optimal use of EPO, integrating administration route and frequency of injections, will reduce the EPO doses needed and minimize cost and side-effects incidence. EPO represents a major advance in the treatment of chronic uremia. EPO opens a new therapeutic era offering for the first time a substitute to a kidney endocrine failure.

Erythropoietin↗
PubMed1992

Platelet-activating factor production during hemodialysis: effect of BN 52021.

Platelet activating factor (PAF) production and platelet-lipoxygenase activity were studied during hemodialysis (HD) with cuprophane membranes. Six patients were treated with first-use dialyzers (FU), and 6 patients with reused dialyzers (RU). In a random and double-blind design, 2 HD were performed for each patient, with or without BN 52021 pretreatment, a selective PAF antagonist. Platelet and leukocyte counts were performed before pretreatment and 30 min before HD starting (T-30), at the beginning of HD (T0) and after 15 and 30 min of HD (T15, T30). PAF production was analyzed by direct phase HPLC. To determine platelet-lipoxygenase activity, 12-HETE was detected by reverse phase high performance liquid chromatography (HPLC) after blood stimulation by the ionophore A23187. In the FU group, PAF and 12-HETE were produced during the first 30 min of HD. After BN 52021 pretreatment, PAF production was suppressed and platelet-lipoxygenase activity reduced. In the RU group, neither PAF nor 12-HETE production occurred, and BN 52021 had no effect. We conclude that PAF, which was involved in both platelet and leukocyte activation that occurred during hemodialysis, can be considered as a bio-incompatibility marker.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

The effects of reprocessing high-flux polysulfone dialyzers with peroxyacetic acid on beta 2-microglobulin removal in hemodiafiltration.

The reuse of dialyzers is widely practiced, especially in the United States. Despite this, the effects of reuse on the efficacy of removal of solutes and more recently proteins such as beta 2-microglobulin (beta 2M) are the subject of much debate. There is considerable evidence to suggest that reuse after cleansing and sterilizing with formalin, with or without bleach, maintains dialyzer performance. In this study, we have examined peroxyacetic acid use as the cleansing and sterilizing agent using Renatron machines. We analyzed reuse in 24 patients using polysulfone membranes in a hemodiafiltration (HDF) unit over a 2-year period. The mean maximum number of uses achieved was 20.1 +/- 0.5. Several factors considered clinically to influence the number of reuses achievable (hemoglobin, white blood cell, and platelet levels, erythrocyte sedimentation rate [ESR], and fibrinogen and total protein levels) were found not to influence the maximum number of uses obtainable. We then assessed prospectively the performance of 26 polysulfone dialyzers after peroxyacetic acid reprocessing up to 20 times, particularly with regard to their ability to remove beta 2M. We report that this combination of polysulfone membranes reprocessed with peroxyacetic acid used for HDF up to 20 times exhibits a maintained high level removal of compounds beyond a molecular weight (MW) of 12,000. Any secondary membrane formation that occurs appears not to influence the subsequent removal of beta 2M. Thus, we would recommend the use of peroxyacetic acid for reprocessing dialyzers in a safe and efficacious manner.

Adult↗
PubMed1992

Failure of a daily haemofiltration programme using a highly permeable membrane to return beta 2-microglobulin concentrations to normal in haemodialysis patients.

In an attempt to return to normal serum beta 2-microglobulin levels in a group of seven ESRD patients, a programme of daily HF with highly permeable AN69 membranes was undertaken. Pre-HF beta 2-M serum levels stabilized after 4 days at 20 mg/l, only 40% lower than the initial concentration. A total of 985 +/- 20 mg beta 2-M was removed over the week. The beta 2-M release rate averaged 97 micrograms/min with a broad range of values (63-128 micrograms/min). beta 2-M release peaked at 602 micrograms/min 1 h after the end of the HF session before returning to baseline by 12 h post-HF. We conclude that a return to normal blood beta 2-M concentrations in ESRD patients seems quite unrealistic despite a highly intensive extracorporeal therapy. Therefore other therapeutic alternatives have to be designed to prevent or cure beta 2-M amyloidosis.

Adsorption↗
PubMed1992

Whole blood serotonin levels are markedly elevated in patients on dialytic therapy.

The normal range for whole blood serotonin levels in chronic renal failure patients has not been defined. As serotonin may be implicated in platelet abnormalities, hypo- and hypertension and itch in dialysis patients, serotonin whole blood levels were measured in a group of patients with chronic renal failure and/or who were dialysis dependent. The levels were elevated in 12 patients with moderate (mean serum creatinine 335 +/- 54 mumol/l) chronic renal failure (270 +/- 46 micrograms/l) compared to 11 normals (163 +/- 17 micrograms/l, p less than 0.05; quoted normal range less than 300 micrograms/l) but did not correlate with serum creatinine levels. There was a marked elevation in serotonin levels in dialyzed patients, including those on hemodialysis (polysulfone, n = 6, 747 +/- 234 micrograms/l; cuprophane membranes, n = 6, 708 +/- 198 micrograms/l), hemodiafiltration (n = 12, 695 +/- 130 micrograms/l) and especially peritoneal dialysis (n = 6, 1,148 +/- 162 micrograms/l). All results were significant (p less than 0.01) compared to normals and compared to the nondialyzed group (p less than 0.05). The level of serotonin decreased during hemodialysis regardless of the membrane used. There was no positive correlation of serotonin levels with pruritus or hypertension, although there was a negative correlation with systolic blood pressure. The reference range for serotonin whole blood levels needs to be broadened when considering dialyzed patients.

Adult↗
PubMed1992

Biochemical characterization of serum and urinary beta 2 microglobulin in end-stage renal disease patients.

Since the identification of beta 2 microglobulin (beta 2-M) in haemodialysis-associated amyloidosis, the biochemical characterization of the different forms of beta 2-M has been sought by several groups. New beta 2-M isoforms (pI 5.1 and lower) have been identified in amyloid deposits, and it has been suggested that they are of pathogenetic importance. The finding of N-terminal proteolysed beta 2-M in amyloid deposits prompted the hypothesis that proteolysis would render beta 2-M more amyloidogenic. Finally, a 'novel beta 2-M' (pI 5.2) with a single amino acid replacement (Asn by Asp at position 17) has been reported as possibly specific for patients with dialysis associated amyloidosis, and consequently proposed as 'the amyloidogenic' form. We purified beta 2-M from serum of a newly haemodialysed patient and from urine of a transplanted patient in the early recovery period. Both patients were clinically amyloid free. Three pure isoforms were obtained from serum (pI 5.7, 5.3, and 5.1) and only two from urine (5.7 and 5.3). Further purification of each isoform was obtained by HPLC in a C4 column. Sequence analysis showed that all isoforms had an intact N-terminus. Tryptic digestion of the serum isoforms was performed after alkylation with iodoacetic acid and the peptides were isolated by HPLC in a C18 column. The 5.3 and 5.1 isoforms had identical peptide patterns with the appearance of an early peak missing in the 5.7 form. The sequence of this peptide showed a replacement of the D 42 (Asp 42) by N (Asn) after K41 (Lys 41).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Hemodiafiltration with on-line production of bicarbonate infusate: 5 years of clinical experience].

Despite its potential advantages HDF has not gained large clinical acceptance among nephrologist due to its technical complexity and to the large quantity of pharmaceutical substitution fluid needed. HDF with on-line production of substitution fluid from dialysate simplifies the procedure and reduces the cost of treatment session. We treated regularly 13 high risk and/or non-compliant patients (9 males, 4 females) with HDF for 46 +/- 17 months. HDF program consisted of 3 sessions weekly lasting 210 +/- 10 mn with blood flow rate 350 +/- 20 ml/mn and fluid volume exchange of 20 liters/session. High flux dialyzers (HF80, Filtral 16) were reused 6 to 13 times automatically on a Renatron machine with peroxyacetic acid solution as sole cleaning and disinfecting agent. Microbiologic quality of infusate was assessed by membrane filtration culturing method and LAL endotoxin determination. 3937 HDF sessions were performed. 57.140 I of substitution fluid were infused IV to patients. Eight pyrogenic reactions were observed: 2 due to septicemia related to catheter infection and 6 from unknown origin. Adequacy of program was achieved in all patients. Blood pressure control was satisfactorily obtained without antihypertensive medication in 12/13 patients. Effective weekly integrated urea clearances was 150 +/- 15 l/wk, KT/V index was 1.50 +/- 0.10, urea TAC 20 +/- 2 mM/l and protein catabolic rate 1.40 +/- 0.10 g/kg/24 h. We conclude that HDF with on-line production of bicarbonate substitution fluid is a safe and highly efficient method cost-competitive with bicarbonate HD, which offers an interesting alternative for renal replacement therapy.

Adult↗