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Copyright of Néphrologie & Thérapeutique is the property of John Libbey Eurotext Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Parathyroid hormone (PTH) is measured in patients with chronic kidney disease (CKD) to evaluate the spread of secondary hyperparathyroidism and to identify renal osteodystrophy subtypes. An important intermethod variability that can significantly influence the clinical decision has been highlighted recently. Similarly, it is acknowledged that the preanalytical conditions are important to optimize the interpretation of a PTH level by comparison with the K/DOQI guidelines. Considering the frequent case of a dialysis patient in whom blood is handled in the evening and addressed to the clinical laboratory the next morning, we have evaluated the stability of the PTH concentration during a 18-hour period. We thus measured PTH with three automated assays in three kinds of tubes (plain tubes with a gel separator, EDTA tubes, EDTA+aprotinin tubes) which were either immediately centrifugated with a prompt freezing of the serum or plasma, or stored for 18hours at room temperature or at 4 degrees C. Our results demonstrate that, whatever the kind of tube, the PTH concentration is not altered by a 18-hour storage at 4 degrees C which is not the case at room temperature. Using a tube with a gel separator necessitates however to centrifugate the tube in the dialysis unit. On the other hand, the use of serum, by contrast with EDTA plasma, allows the measurement of other biological parameters including calcium, does not need that the tube is fully filled and, according to our results, reduces the intermethod variability. In conclusion, this study shows that the measurement of PTH may be delayed by 18hours if the primary tube is kept at 4 degrees C. Assuming that the primary tube is centrifugated but not opened in the dialysis unit, serum may be the sample of choice for the measurement of PTH in patients with CKD.

The working group PTH-Vitamin D of the SFBC recently underlined the great intertechnic variability of parathormone (PTH) assays. At the same time, the data of the literature showed an impact of the preanalytic stage, significant and variable according to the automat used. We worked on the automat Roche Elecsys. On quickly centrifuged and decanted samples, the small difference in results between serum and plasma EDTA (6%) is compatible with an indifferent use of the two samples for dialysed patients. The reputation of greater stability on plasma EDTA seems primarily based on studies after decantation of plasma. The extension to a non decanted sample, maintained on primary tube for deferred shipping to the laboratory would require verification. Concerning the serum, on tube with serum separator, after early centrifugation, we checked the stability of the PTH measurement for a delay lower than or equal to 4 hours. For an extrahospital structure of dialysis, in the conditions of an early and an on site centrifugation, this delay allows to defer the transport of the primary closed tube to the laboratory. Contrary to plasma EDTA, the serum also allows simultaneous measurements of other parameters used for the care of the dialysed patients.

Objectives: To identify biochemical risk factors specific to each crystalline phase of calcium oxalate (calcium oxalate monohydrate and calcium oxalate dihydrate) in order to allow more specific medical management of calcium oxalate stones and better prevention of recurrences., Material and Methods: The authors compared the urine biochemistry (morning and 24-hour) of 19 patients with stones containing more than 95% of calcium oxalate monohydrate with those of 16 patients with stones containing more than 60% of calcium oxalate dihydrate (calcium phosphate < 12%)., Results: Urinary calcium, expressed as excretion rate and as concentration, and the calcium/citrate ratio were significantly higher in the calcium oxalate dihydrate group than in the calcium oxalate monohydrate group: (9.2 +/- 3.8 mmol/24 h versus 4.4 +/- 1.7 mmol/24 h); (4.9 +/- 2.1 mmol/l versus 2.4 +/- 1.1 mmol/l); (3.3 +/- 1.6 versus 1.6 +/- 0.7). The mean pH of the morning urine was lower in the calcium oxalate monohydrate group, just below the cut-off value of 5.5., Conclusion: There is a strong correlation between predominantly calcium oxalate dihydrate stones and hypercalciuria or calcium/citrate ratio > 3. The close relationship between urine biochemistry and crystalline phases of calcium oxalate confirms the clinical value of morphoconstitutional analysis of urinary stones. Identification of risk factors, based on stone analysis, allows more specific medical management of the stones and, in the longer term, better prevention of recurrences.

Retrospective studies of CAPD show a 50% patient survival at 5 years. There are actually three long term technique limits: UF failure: The diagnosis is made clinically and by peritoneal permeability tests. The use of new osmotic agents should improve this problem. Inadequate dialysis seems more related to the low dialysate flow rather than to the peritoneal membrane. The increase of dialysate volumes or the switch to Automated PD leads to better clearances. The peritoneal membrane lesions are generated by the use of an aggressive dialysate. In order to protect the membrane, new biocompatible solutions are under evaluation.

In a retrospective study, the authors analyse the dialysis-technique success rate in 276 chronic renal patients. 137 patients have been treated with in-center Hemodialysis (CHD) since 1972, 139 patients with Continuous Ambulatory Peritoneal Dialysis (CAPD) since 1978. The 6-year technic success rate reaches 28% in CAPD and 31% in CHD (not statistically significant). The risk factors influence the technic-success rate of both methods in the same way. The results suggest that in the analysed patients CAPD is at least as effective as CHD at maintenance in the technic.

Experience influence on treatment success of renal chronic failure by continuous ambulatory peritoneal dialysis comparatively to hemodialysis in center is estimated by the probability variation of still being in dialysis techniques. The retrospective study was realized in 276 dialysed patients who were taken over from 1972 to April 1989. In this population, there isn't any significant difference between the probability to stay in ambulatory peritoneal dialysis or in hemodialysis in center. But, if the study is realizing from the 4 years which followed the technique introduction in the center, the success probability at 30 months, remains the same for hemodialysis in center whether the technique has began in 1972 or 1976, whereas for continuous ambulatory peritoneal dialysis, this probability raises from 52% to 72% if it begins after 1982. Ambulatory peritoneal dialysis treated patients would be maintained more longer in their system than hemodialysis patients. Those results are explaining by prevention of the peritonitis thanks to technological progress and the early prevention of possible complications.

The authors report their experience on treating two patients, suffering end-stage renal disease, by daily hemodialysis of ultra-short duration with a non-traumatic vascular access. 90 minutes dialysis are realized 6 days a week. Clinical tolerance is excellent and patients' adhesion is satisfactory. However, despite reutilization of the dialyzer, the method remains costly.

The computerized medical specialized records covering the follow-up of hypertension (ARTEMIS), diabetes (MELLITEE), chronic renal failure and the minimum medical record of Nephrology (THESEE) using the temporal database management system LIED, have been developed in several units of University Hospitals. The authors show that these computerized records are usable in a Nephrology Unit in a General Hospital.

During CAPD, the peritoneal cavity is submitted to situations such as the accidental bacterial contaminations and the continuous presence of dialysate, which stimulate immunological factors. The antibacterial defenses include opsonins and cells. Only IgG and fibronectin are present in the peritoneal effluent but they are diluted by the dialysate. Macrophages represent 70 to 80% of the peritoneal cells. Beside good phagocytic capacity, some may have a defective bactericidal activity. The continuous presence of dialysate leads to a chronic local inflammation. Macrophages and lymphocytes will synthesize IL-1, PGE2 and IFN-Y. These substances generate movement, attachment and proliferation of fibroblasts in the peritoneal submesothelial tissue, resulting in progressive fibrosis. This fibrosis, generally asymptomatic, may be responsible for loss of Ultrafiltration (UF) and Sclerosing Encapsulating Peritonitis (SEP).

The authors report the result obtained with CAPD in 20 chronic renal patients treated during 4.6 years in average. The dialysis possibilities have maintained at middle term. Nevertheless, the awaited advantages concerning anemia, calcium and phosphorus disorders, neuropathy, are transient and incomplete. The water and sodium intakes need strongly to be controlled in order to achieve normal blood pressure. Finally the use of "Y" disconnect systems dramatically reduces the peritonitis rate.

Using the "Diaphane" computed medical record system enables multicentric statistical studies to be conducted. With this system, the quality of arterial hypertension control (supine systolic and diastolic arterial pressure before and after dialysis) was evaluated over a 10-year period in chronic haemodialysis patients in comparison with a multicentric population. A continuous statistical study of the results showed a regular voluntary decrease in arterial pressure. The evaluation of the quality of medical care represented by this comparison contributes to a therapeutic improvement.

"ARTEMIS" is a standardized and computerized medical file which is intended for improving the follow-up of hypertensive patients, the efficacy of treatment and for realising national-wide surveys. The software "LIED" of data base for "ARTEMIS" is nowadays transposable on mini-computer. In Nephrology Unit of General Hospital from Colmar, the system has been working since September 1985 with MICRO-MEGA E 32 (Thomson). The administrative and medical data are directly acquired by the doctors and secretaries of the Unit on a conversational mode from six terminals. There is no writing collecting of data. An evaluation of the system was realized with the 113 first hypertensive patients. The results were compared to those obtained from patients of Paris area.