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Biomedical subjects

M el Mehdi

Publications and source records attributed to M el Mehdi.

4 recordsLinked to original sources

A continuous hemofiltration system using sorbents for hemofiltrate regeneration.

Plasma ultrafiltrate obtained by glomerular filtration undergoes tubular modification which leads to the elimination of toxic substances, excess water and electrolytes, and consequently maintains homeostasis. Using normal urine and the substances it contains as a reference, we have developed a wearable device capable of replacing both the renal excretion function and maintaining fluid and electrolyte equilibrium in uremics within acceptable biological limits. Our device includes a hemofilter allowing continuous plasma ultrafiltration and sorbents obtained from a Redy sorbent cartridge to treat 85% of the ultrafiltrate, whereas 15% of this UF is rejected untreated. After calculating the quantity of ultrafiltrate (about 13 l) containing an amount of waste products of metabolism equivalent to 24-h urine elimination, we determined in vitro the amount of sorbent required to eliminate these waste products from the ultrafiltrate (e.g., 20 g of urea/day) and we have evaluated the quantities of other substances which must be replaced using a tailored diet. This extra-corporeal detoxification process was used in a uremic patient who had been on traditional hemodialysis for the past two years. The continuous treatment permitted maintenance of fluid and electrolyte equilibrium at the desired level and allowed rapid improvement of patient clinical status: elimination uf nausea, vomiting, diarrhea and edema, which had previously reappeared during the interdialytic periods, as well as a rapid decrease in heart size as ascites disappeared. In addition, the patient regained sexual drive and the ability to have an erection. In conclusion, traditional hemodialysis and hemofiltration techniques allow intermittent elimination of products retained by the body and reestablish nearly normal fluid and electrolyte balance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗

Intra-erythrocytic sodium in uremic patients, as determined by "high-resolution" 23Na nuclear magnetic resonance.

The use of 23Na nuclear magnetic resonance with aqueous shift reagent has made it possible to determine intracellular sodium concentrations in living erythrocytes. We applied this technique to samples from 16 healthy subjects and 41 uremic patients. The results seem to show distinct populations among the latter. Classically, two different relaxation times are obtained for intracellular sodium in biological media, according to relaxation NMR theory. Some patients, however, exhibit abnormal results that cannot be accounted for by this theory.

Adult↗

Sequential sodium therapy allows correction of sodium-volume balance and reduces morbidity.

We investigated whether individually adjusting Na+ dialysis levels (Na+Di) combined with Na+ and UFR (ultrafiltration rate) programming, and a sodium/volume model (sequential sodium therapy, SST) can improve the end stage renal failure (ESRD) patient's homeostatic equilibrium intra- and interdialytically. One hundred and fifty patients were included in the study over a one year period. The results show that the patients are divided into two groups: 50 patients respond according to the sodium/volume model developed by F. Gotch [1983]. In this group it is possible to predict pre- and post dialysis plasma Na+ concentration (Na+o, Na+t) as a function of Na+Di and it becomes possible to choose Na+Di to allow Na+o and Na+t to virtually coincide, eliminating severe shifts in plasma tonicity. In the second group two subgroups can be distinguished: excess Na+ or excess H2O post dialysis, without possible correction at a single sodium level. SST corrects sodium/volume balance in this group by using sequential intermittent hypo or hypertonic dialysate, combined with fluid removal adapted to each episode. In both groups there was a significant improvement in the clinical condition of the patients who previously were less equilibrated. It is possible to conclude that SST improves tolerance intradialytically and achieves better equilibrium interdialytically. Implementation of SST requires precise control of the concentrate and the water, and equipment adapted for accurate, programmable sequential control of Na+Di and ultrafiltration rate.

Adolescent↗