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Biomedical subjects

N K Man

Publications and source records attributed to N K Man.

At least 73 records · Page 4Linked to original sources
PubMed1987

[Treatment of chronic kidney failure by the keto-analogs of essential amino acids: 4 years' experience].

From June 1981 to June 1985, 22 patients with advanced chronic renal failure were treated with a preparation of ketoanalogues of essential amino acids (Ketosteril, 1 tablet/5 kg/day) combined with a protein supply of 0.4 g/kg/day. At the beginning of treatment, their mean plasma creatinine was 762 +/- 135 mumol/l and their creatinine clearance, 8.4 +/- 3.1 ml/min/1.73 m2. By the end of November, 1985, among the 20 assessable patients, 4 had been on ketoanalogues for 8 to 52 months, 9 had to be dialyzed after 4 to 20 months, 5 had died and 2 had abandoned treatment. A mean 28% decrease in plasma urea level and daily urinary urea output was observed after 1 month on ketoanalogues, and a sustained reduction in plasma creatinine was observed in 12 patients. Mean renal survival was 15.6 +/- 12 months (median: 12 months), and was longer in patients whose plasma creatinine was lower than 700 mumol/l at the beginning of treatment. The ketoanalogues were well tolerated, and no denutrition occurred. Our experience confirms the usefulness of this therapeutic approach in uremic patients and suggests that the best results would be obtained if ketoanalogues were introduced before end-stage renal failure.

Adult↗
PubMed1987

[Functions and metabolism of polynuclear neutrophils in patients under chronic hemodialysis].

Clinical evidence indicates that infection is still a cause of morbidity and mortality in patients undergoing hemodialysis. The major role played by the polymorphonuclear cells in antimicrobial response by the host explained considerable study of several aspects of granulocyte functions in chronic hemodialysis patients. It is now well documented that hemodialysis induces the sequential activation of the complement components of the alternative pathway and may provide a mechanism for initiating leukoaggregation and sequestration of granulocytes. This complement activation could also explain the profound leukopenia observed shortly after the initiation of hemodialysis. It has been also assumed that the sequestration of granulocytes is dependent on a temporarily altered cell function and leads to a depressed chemotaxis, an impairment of phagocytic and bactericidal capacities. Moreover, a significant defect in the oxidative metabolism was observed before and during the course of the dialysis session. This article summarizes research that has been done on the function of neutrophils from chronic hemodialysis patients.

Blood Bactericidal Activity↗
PubMed1986

[Effect of keto analogs of essential amino acids on the progress of advanced chronic renal insufficiency: controlled prospective study].

We prospectively compared the efficacy and tolerance of a very low protein intake (0.4 g/kg/day) supplemented with keto analogues of essential amino acids and of the standard low protein diet (0.6 g/kg/day) in 19 patients with advanced chronic renal failure (mean plasma creatinine level: 726 +/- 113 mumol/l), who were randomly assigned to either treatment. Long term acceptability was similarly good in both groups and no biochemical or morphometric sign of denutrition was observed in neither group, whereas the mean renal survival duration until dialysis was longer, and the mean slope of 1/Cr was lower in patients treated with keto analogues. We suggest that ketoacid treatment is more effective than protein restriction alone in slowing the progression of advanced chronic renal failure.

Adult↗
PubMed1985

Clinical validation of a predictive modeling equation for sodium.

Changes in plasma sodium (Na) concentration during hemodialysis were predicted by changes in Na concentration of the dialysate at equilibrium with the plasma, according to the formula C't = CD - (CD - C'0) [(V0 - QFt)/V0]A/QF, where C'0 and C't are the Na concentration of the dialysate at equilibrium with the plasma at times 0 and t, respectively; QF is the ultrafiltration flow rate; V0 is the initial total body water; and CD is the Na dialysate concentration. This modeling involves only one parameter, A, which is the effective sodium dialysance and depends on the dialyzer, the QF, the plasma water flow rate, and the actual Donnan coefficient. Parameter A was evaluated after 1 h of dialysis. Seven routine 4-h dialysis sessions were performed in which the Na concentration of dialysate at equilibrium with the plasma was measured at varying times. The mean (+/- SEM) difference between predicted and measured values was delta C = 0.5 +/- 0.2 mmol/L. These data support the validity of the model that allows the monitoring of Na dialysate concentration to obtain a prescribed Na plasma concentration at the end of a dialysis session.

Humans↗
PubMed1985

Concomitant removal of aluminium and iron by haemodialysis and haemofiltration after desferrioxamine intravenous infusion.

In six anuric haemodialysed patients, aluminium and iron mass transfer were determined 48 hours after 40 and 80mg/kg body weight desferrioxamine intravenous infusion. All patients were aluminium overloaded (mean +/- SEM: 2.91 +/- 1.05 mumol/g wet tissue bone) and two had high plasma ferritin. Haemodialysis and haemofiltration were performed using a highly permeable membrane. The adequate dose of desferrioxamine for aluminium removal is 40mg/kg, since aluminium mass transfer induced by haemodialysis and haemofiltration (47.4 and 40 mumol/session) are not significantly different from that obtained with 80mg/kg. Iron removal is dose related in high plasma ferritin concentration patients: 50 and 100 mumol/session with haemodialysis and 29 and 175 mumol/session with haemofiltration after 40 and 80mg/kg body weight respectively.

Adult↗
PubMed1985

[Modelling in hemodialysis. Why? How?].

It is an imperative necessity to adapt dialysis therapy patient to patient. This adaptation of dialysis procedure requires appropriate representation of water and solute exchanges. Kinetic modelling of hemodialysis was investigated in this respect. The goal of kinetic modelling is either to estimate one or several biologic parameters which are not easily measurable or to reach a prerequisite optimal physiologic state for a given patient. Constructing a model implies a physiological conception of solute and water exchanges that allows a definition of biologic parameters concerned. Mathematic equations only translate quantitatively water and solute transfers. A suitable model is in agreement with experimental data, and the best is the simplest. Therefore the capital point resides in the choice of assumptions which determine the model's precision and complexity. This review also outlined the limits of kinetic modelling which allows neither the determination of the best target nor the "a posteriori" justification of assumptions.

Body Fluid Compartments↗
PubMed1984

Drug interaction in middle molecule analysis, with special reference to acetylsalicylic acid.

Concerning the middle molecules in uremia and other diseases, the potential artifact that can impede an accurate quantitation of middle molecules and that is related to the absorption of a very commonly used drug, namely aspirin, is discussed. Peak 7c and peak b 4-2 are two different middle molecules separated by gel permeation chromatography followed by anion-exchange chromatography. Oral ingestion of acetylsalicylic acid modifies the chromatographic pattern of the middle molecule fraction in normal subjects and uremic patients. Peak 7c is increased in the urine of healthy subjects, whereas this is not the case for peak b 4-2: With the b 4-2 technique, ingestion of acetylsalicylic acid produces a higher peak b 5. This is consistent with the previous demonstration that peak 7c was eluted as peak b 5. Structural analogies between salicylate metabolites and orthohydroxyhippuric acid beta-glucuronate (i.e., the main component of peak 7c) could explain this drug-related artifact.

Aspirin↗
PubMed1984

Sodium modeling during hemodialysis: a new approach.

Sodium volume modeling during hemodialysis encounters several difficulties. First, the actual sodium distribution volume is the extracellular water, whereas the ultrafiltration flow reflects the variation of total body water. Thus, a two-pool model must be considered. This will complicate the model by increasing the number of parameters and boundary conditions. An alternative is to consider the total body water as the apparent distribution volume of loaded or removed sodium, which leads to a single-pool model. Second, convective sodium transfer induced by ultrafiltration is not negligible compared with diffusive sodium transfer. Therefore, sodium transfer modeling must simultaneously take into account the diffusive and the convective part, with the coupling part related to both processes. Third, the Donnan effect due to nondiffusible anionic plasma proteins modifies the sodium transfer through the membrane. Adequate sodium volume modeling should be a compromise between oversimplification, resulting in discrepancies between calculated values and experimental data, and overcomplexity, involving a great number of parameters and boundary conditions, which leads to a model unsuitable for clinical application. A single-pool model is proposed with only one parameter that is estimated during the first period of the hemodialysis session.

Body Water↗
PubMed1984

Optimization of Na content of dialysis fluid.

The design of a dialysate recirculating llop permitted assessment of dialysate/blood Na+ dialysate concentration of 136.6 mEq/l (Donnan effect). Sodium and water removal using different Na+ dialysate concentrations have been assessed. With an Na+ dialysate concentration of 130 mEq/l plasma clearance of Na+ and H2O are equal, NNa/NH2O=128-142. Using a dialysate Na+ concentration of 162 mEq/l, NNa/NH2O=40-61, i.e., Na+ clearance is much lower than H2O clearance. The average patient requires removal of 2 liters H2O and 200 mEq Na+, i.e., NNa/NH2O=100. This corresponds to an Na+ dialysate concentration of 145 mEq/l. The incidence of hypotensive episodes during dialysis will be reduced if NNa/NH2O ratios (Na+ dialysate concentrations) are individualized for hemodialysis patients.

Body Water↗
PubMed1984

[Self dialysis: a new method of treatment for end-stage renal disease].

Self-hemodialysis in a limited-care facility could be a good alternative for patients who are reluctant to home dialysis for several reasons. Through reduction of nursing personnel and elimination of physician attention at each dialysis, self-hemodialysis in a limited-care facility, where the patient dialyses himself and cleans his own machine without assistance, has reduced the cost to about one-half of center cost. From March 1980 to December 1982, out of 65 dialysed patients from Beauce and Perche Area, 33 patients were treated in the Hemodialysis Unit-Chartres Hospital (50.8%), only 5 were on home dialysis (7.6%), 15 were on CAPD (23.1%) and 12 were on self-hemodialysis in a limited-care facility (18.5%). Self-hemodialysis is a practical addition to various modalities treating end-stage renal disease and, in our experience, full compliance to the dialysis regimen was achieved in all patients.

Adult↗