Cystatin C improves the diagnosis and stratification of chronic kidney disease, and the estimation of glomerular filtration rate in diabetes.

AIMS: Estimation of glomerular filtration rate (GFR) is recommended to diagnose and stratify chronic kidney disease (CKD). Can cystatin-C (cysC) assay improve the results in diabetic patients? METHODS: In 124 diabetic patients with a wide range of GFR, as determined by 51Cr-EDTA clearance (i-GFR), we estimated 'e-GFR' by: the recommended Cockcroft-Gault (CG) formula and Modification of Diet in Renal Disease (MDRD) study equation; the new Mayo Clinic quadratic (MCQ) equation; the recently proposed composite estimation including both serum creatinine and cysC; and a simplified approach dividing the MDRD by cysC if less than 1.10mg/L. RESULTS: The highest diagnostic accuracy (receiver operating characteristic [ROC] curves) and the highest proportions of well-stratified patients were obtained by cysC and the MDRD which, however, underestimated i-GFR for patients without CKD (-17%, P<0.001). The CG overestimated GFR in KDOQI stages 1 and 2, ignored stage 5 and was the least accurate. The MCQ equation overrepresented stage 2, overestimating GFR at this stage (+23%, P<0.005). The composite estimation (54.7+/-27.0mL per minute 1.73m(2)) correlated best with i-GFR (56.1+/-35.3; r=0.90, P<0.001), and did not significantly differ from it across the entire population and within each Kidney Disease Outcome Quality Initiative (KDOQI) stage but was also biased (Bland-Altman procedure). Simply dividing the MDRD by cysC ifless than1.10mg/L produced a comparable performance and eliminated the bias. CONCLUSION: The recommended creatinine-based estimations of GFR need to be improved. CysC assay helps in the diagnosis and stratification of CKD and leads to better estimates of GFR in diabetic patients without any substantial increase in complexity.

[Low protein diet supplemented with ketoanalogues of amino acids in patients with chronic renal insufficiency]. / Régime pauvre en protéines supplémentés par les céto-analogues des acides aminés chez le patient atteint d'insuffisance rénale : pour qui ? Comment ?

Restricted protein diets in patients with chronic kidney disease have been debated for several decades. In chronic kidney disease as in other chronic diseases, the modulation of the nutritional intake is the object of a certain renewal. It is supported by recent studies that highlight the importance of modulating nutrient intake by diets that are healthier, less rich in animal proteins and richer in plants. The recent reintroduction in France of amino acid supplements and ketoanalogs of amino acids allows the prescription of a very restricted diet. Historical studies have only focused on the relationship between protein intake and renal function degradation. Recent studies on acid loading, bone metabolism or potassium intake allow revisiting the interest of restricted diets. As with any change in eating habits, the selection of patients, information, education and monitoring during the diet are very important and help prevent undernutrition: this is the purpose of this short review.

A simplified Cockcroft-Gault formula to improve the prediction of the glomerular filtration rate in diabetic patients.

AIM: The National Kidney Foundation recommends stratification of renal failure into moderate (Glomerular Filtration Rate: GFR = 30-60 mL/min/1.73 m2), severe (15-30) or terminal (<15) using the Cockcroft-Gault (CG) or the Modification of Diet in Renal Disease (MDRD) equations. We studied the biases in these methods in an attempt to improve the standard CG (MCG) and devise a strategy for stratification. METHODS: GFR was measured by 51Cr-EDTA clearance in 200 diabetic patients: 100 (Group 1: study of concordance) before 2003 and 100 thereafter (Group 2: validation of MCG). The CG was modified by replacing body weight by its mean value: 76. RESULTS: In group 1, the recommended equations only correctly stratified 50 patients. The CG, not the MDRD, underestimated GFR if BMI was normal, and overestimated it in obese patients. In group 2, the MCG was well correlated with GFR and not biased by weight. Over the whole population, the MCG and MDRD were more accurate for the diagnosis of moderate and severe renal failure. The MDRD showed the lowest differences with GFR, except if GFR > 60, where the MCG performed better. All formulae overestimated low GFR, the MDRD also underestimated high GFR. The best stratification (147/200) was obtained using the MCG if creatininemia < 120 micromol/l and the MDRD if creatininemia > or =120 micromol/l. CONCLUSION: The CG is biased by weight, the MCG corrects this. The more accurate MDRD cannot be used in all patients as it underestimates high GFR. The best stratification was obtained using the MCG at low and the MDRD at high creatininemia.

Thymoma associated with myasthenia gravis and minimal lesion nephrotic syndrome.

A nephrotic syndrome has been observed rarely in association with thymoma. In most of the reported cases, it occurs when the thymoma is in remission; histological examination generally shows minimal change disease. We report a case of a 43-year-old man presenting with minimal lesion nephrotic syndrome at the time of the diagnosis of thymoma and myasthenia gravis, which persists despite remission of the thymoma. The role of a disorder of T-cell function and of circulating cytokines is discussed.

Scale-up and design of a pilot-plant photobioreactor for the continuous culture of Spirulina platensis.

Scale-up of bioreactors has the intrinsic difficulty of establishing a reliable relationship among physical parameters involved in the design of the new bioreactor and the physiology of the cultured cells. This is more critical in those cases where a more complex operation of the bioreactor is needed, such as in photobioreactors. A key issue in the operation of photobioreactors is establishing a quantification for the interaction between external illumination, internal light distribution and cell growth. In this paper an approach to the scale-up of a photobioreactor for the culture of Spirulina platensis, based on a mathematical model describing this interaction, and the operation of a previous reactor 10 times smaller is presented. The paper describes the approach followed in the scale-up, the analysis of different design constraints, the physical realization of the new bioreactor design, innovative use of plastic material walls to improve reactor safety, and finally the corroboration of its satisfactory operation.

Resting energy expenditure in uremic, diabetic, and uremic diabetic subjects.

We compared Harris and Benedict [H & B; Harris, J. A., & Benedict, F. G. (1919). A biometric study of basal metabolism in man. Washington, DC: Carnegie Institution of Washington. p. 279.] predicted resting energy expenditure (REE) to values measured by indirect calorimetry in normal, uremic, diabetic, and uremic diabetic subjects. Predicted REE were overestimated (+9.2%, P<.005) in uremic subjects, and underestimated (-8.5%, P<.0001) in diabetic subjects. Uremic diabetic subjects were submitted to the opposite influences of diabetes and uremia on REE. Differences in body composition (lower fat-free mass in uremia and higher fat-free mass in diabetes) played a major role in these influences. In uremic diabetic subjects, predicted REE seemed well fitted to measured REE (biases <2%), but they were less correlated, and limits of agreement between predicted and measured REE were large. Although their mean REE seems normal, prediction by the H&B equation leads to important individual errors in uremic diabetic subjects: direct measurement of energy expenditure by indirect calorimetry may be helpful to precise the adequate energy content of a diet for these subjects.

Impact of high-flux/high-efficiency dialysis on folate and homocysteine metabolism.

High-flux/high-efficiency (HF/HE) dialysis may have detrimental effects on micro-nutrients and water-soluble vitamins, such as vitamin B6, whose levels are lowered. Folate deficiency may increase cardiovascular risk through an increase in homocysteine (Hcy) serum levels. We therefore investigated the effects of dialysis with a high-flux (HF) membrane on folate and Hcy metabolism. Twelve patients without any folate supplementation, receiving dialysis with a low-flux membrane prior to the study (TO), were switched to dialysis using a HF triacetate membrane for four months (T1, T2, T3, T4) and received an oral daily folate supplementation during the two last months (T3, T4). Mean predialysis plasma folate levels fell dramatically after one month of HF dialysis (T1) and remained significantly lower than the initial level (p<0.05) at T2. Hcy concentrations were high in all patients at TO (mean 47.3 +/- 17.6 microM, normal range 5 to 15 microM). They did not change during the first two months of the study but dropped steeply after the beginning of oral folate supplementation. Folate supplementation should be used in HF/HE dialysis to avoid folate depletion. The combination of folate supplementation and HF/HE may lower Hcy levels and reduce cardiovascular morbidity and mortality in these patients.

Determinants of arterial compliance in patients treated by hemodialysis.

BACKGROUND: Cardiovascular disease is the principal cause of morbidity and mortality among hemodialysis patients. Several studies have demonstrated the importance of a reduction in arterial compliance in the development of cardiovascular complications, reflecting the interaction of functional and structural alterations of the peripheral arterial system and left ventricle. The aim of the present study was to demonstrate that arterial compliance, evaluated by automated recording of the QKd interval, was lower in hemodialysis patients than in normal subjects. A secondary objective of the study was to assess the influence of several factors, including calcium-phosphorus parameters, on decreased arterial compliance in these patients. PATIENTS AND METHODS: Arterial compliance was evaluated in 24 chronic hemodialysis patients who had normal (n = 12) or high blood pressure (n = 12), using a method of measuring systolic wave velocity by automated recording of the QKd interval. This interval corresponds to the time (in ms) between the onset of the electrocardiogram QRS complex (Q) and the Korotkoff (K) sound at diastolic pressure (d) heard over the brachial artery during blood pressure measurement. The analysis was performed in comparison with reference values obtained in a population with normal renal function. The other parameters determined were: age, duration of chronic renal failure, duration of hemodialysis therapy, left ventricular mass, vascular calcification score, serum total and ionized calcium, phosphorus, parathyroid hormone, calcidiol, calcitriol, and blood concentration of hemoglobin. RESULTS: The arterial stiffness of all the patients was increased significantly (p < 0.001) compared to reference values obtained from subjects without renal failure, the average age, height, and blood pressure of whom were similar to those of the patients. Multivariate analysis demonstrated a positive relationship among the QKd interval, serum total calcium, and the duration of hemodialysis. This suggested that arterial wall elastic properties were dependent not only on hypertension and constraints of pressure, but that they were also influenced by calcium and phosphorus metabolism and the duration of renal substitution therapy. CONCLUSIONS: Arterial compliance, evaluated by the ambulatory method of QKd measurement, is reduced in chronic hemodialysis patients, and is inversely correlated with serum calcium concentration and dependent on the previous duration of hemodialysis therapy.

Biological life support for manned missions by ESA.

The anticipated evolution of life support technologies for ESA, considering both the complementary life support system requirements and the missions' characteristics, is presented. Based on these results, promising biological life support technologies for manned space missions have been selected by ESA either for their intrinsic ability and performance in effecting specific tasks for atmosphere-, water-, waste-management versus physico-chemical alternatives and/or for longer-term application to a more ecological concept (CES) focusing ultimately on food production. Actual status and plan for terrestrial and space testing of biological life support presented focusing on the "task specific" decontamination technology of the Biological Air Filter (BAF), and on food reprocessing technologies from biodegradable wastes with the MELISSA microbial ecosystem.

Subjective global assessment of nutrition a useful diagnostic tool for nurses?

UNLABELLED: Malnutrition in maintenance haemodialysis (HD) patients is closely related with morbidity and mortality in this population. AIM OF THE STUDY: To evaluate feasibility, performance and information given by SGA (subjective global assessment), a semi-quantitative method of nutritional evaluation (based on a medical questionnaire and a simple clinical examination) carried out by a group of 12 nurses. METHOD: In March 1999, a feasibility study was organised to evaluate 9 patients during HD. Since July 1999, a nutritional evaluation of all the patients meeting the required parameters (e.g. duration of HD > 6 months, day sessions) has been set up every 4 months. RESULTS: In March 1999, preliminary results demonstrated an average learning time per SGA of 15'. In July 1999, 32 patients were evaluated, albuminemia (micromol/l) and pre-albuminemia (g/l) were analysed according to the SGA classification (A = good nutrition, B= light to moderate malnutrition, C= severe malnutrition). The albuminemia and the prealbuminemia of patients A (respectively 541+/-45 and 0.37+/-0.10) were higher than those of patients B (482+/-41 and 0.31+/-0.01), and those of patients C (381+/-54 and 0.19+/-0.1), by variance analysis (p < 0.0001). The information drawn from the SGA reveal a severe malnutrition, a light to moderate malnutrition, and good nutrition in respectively 13%, 63% and 25% of the patients, and a noticeable muscular atrophy (moderate to severe) in 43% of cases. Anorexia and major gastro-intestinal symptom (nausea, vomiting, and diarrhoea) are found in 14% of cases. CONCLUSION: Beside traditional methods of screening and evaluation of malnutrition in HD patients, the use of SGA by a nursing team uncovers useful information on nutritional status of patients, especially in areas lacking facilities such as a laboratory, dietetic department or permanent presence of doctors.

The C23A: first step to a monitoring system of CELSS in flight.

Studies for every level of CELSS: Waste processing, food production, photosynthesis system, and so on ..., imply an automatic system to control, command and quantify gases, water and chemical compounds. Used for many years in plant physiology studies, the C23A system monitors the analysis and quantifies gases (O2, CO2. N2, ...), physical parameters (temperature, humidity, ...) and chemical compounds (NH4+, N03-, ...) on numerous experiments. In the new version, the architecture of the computing system is near of the space requirements. We have chosen a structure with three independent levels: acquisition, monitoring and supervision. Moreover, we use multiplexed analysers: IRGA, mass spectrometer and cheminal analyser. The multiplexing increases the accuracy of the measurements and could facilitate the spatialization. Thus the whole structure anticipates the entire separation between automation in space and control-command on ground.

Recycling efficiencies of C, H, O, N, S, and P elements in a Biological Life Support System based on microorganisms and higher plants.

MELiSSA is a microorganism based artificial ecosystem conceived as a tool for understanding the behavior of ecosystems and developing the technology for future Manned Space Missions. MELiSSA is composed of four compartments colonized by the microorganisms required by the function of this ecosystem : breakdown of waste produced by men, regeneration of atmosphere and biosynthesis of edible biomass. This paper reports the mass balance description of a Biological Life Support System composed of the MELiSSA loop and of a Higher Plant Compartment working in parallel with the photosynthetic Spirulina compartment producing edible biomass. The recycling efficiencies of the system are determined and compared for various working conditions of the MELiSSA loop with or without the HPC.

MELISSA: global control strategy of the artificial ecosystem by using first principles models of the compartments.

MELISSA is a micro-organisms based ecosystem conceived as a tool for understanding the behaviour of artificial ecosystems, and developing the technology for a future biological life support system for long term space mission. The driving element of MELISSA is the recovering of oxygen and edible biomass from waste (faeces, urea). Due to its intrinsic instability and the safety requirements of manned missions, an important control strategy is developed to pilot this system and to optimize its recycling performance. This is a hierarchical control strategy. Each MELISSA compartment has its local control system, and taking into account the states of other compartments and a global desired functioning point, the upper level determines the setpoints for each compartment. The developed approach is based on first principles models of each compartment (physico chemical equations, stoichiometries, kinetic rates, ...). Those models are used to develop a global simulator of the system (in order to study the global functioning). They are also used in the control strategy, which is a non linear predictive model based strategy. This paper presents the general approach of the control strategy of the loop from the compartment level up to the overall loop. At the end, some simulation and experimental results are presented.

MELISSA: a potential experiment for a precursor mission to the Moon.

MELISSA (Micro-Ecological Life Support System Alternative) has been conceived as a micro-organism based ecosystem intended as a tool for developing the technology for a future artificial ecosystem for long term space missions, as for example a lunar base. The driving element of MELISSA is the recovering of edible biomass from waste, CO2, and minerals with the use of sun light as energy source. In this publication, we focus our attention on the potential applications of MELISSA for a precursor mission to the Moon. We begin by a short review of the requirements for bioregenerative Life Support. We recall the concept of MELISSA and the theoretical and technical approaches of the study. We present the main results obtained since the beginning of this activity and taking into account the requirements of a mission to the Moon we propose a preliminary experiment based on the C cycle of the MELISSA loop.

[Rheumatoid purpura in adults. Retrospective study of 38 patients]. / Le purpura rhumatoïde de l'adulte. Etude rétrospective de 38 malades.

The authors report retrospectively 38 cases of Schönlein-Henoch purpura (20 males, 18 females; median age, 26 years). Skin (37/38) and joint (21/38) manifestations are similar to those seen in children. Gastro intestinal (22/38) manifestations are less complicated. Long term outcome of the disease depends on kidney's involvement (32/38) and is severe: chronic renal failure in 31%.

[Value and limitations of the endomyocardial biopsy in HIV infection]. / Intérêt et limites de la biopsie endomyocardique au cours de l'infection par le VIH.

The authors evaluated the interest of endomyocardial biopsy in 19 consecutively hospitalized patients with AIDS. Histopathological study dit not exhibit opportunistic infection but showed aspecific myocarditis in nine patients.

[A new threat: Xanthomonas maltophilia infection. Apropos of 50 cases]. / Une nouvelle menace: l'infection à Xanthomonas maltophilia. A propos de 50 observations.

In an attempt to further characterize infections due to Xanthomonas maltophilia (XM), we reviewed 50 case reports observed in our institution. XM is emerging as an important nosocomial pathogen in immunocompromised patients, especially those receiving broad spectrum antimicrobial antibiotherapy. Distinction between colonisation and infection is often difficult. XM presents a therapeutic challenge because of its tendency to exhibit multiple resistance.

[Xanthomonas maltophilia nosocomial infections. A new threat. Apropos of 30 cases]. / Infections nosocomiales à Xanthomonas maltophilia. Une nouvelle menace. A propos de 30 observations.

In an attempt to further characterize infections due to Xanthomonas maltophilia, we reviewed 20 colonisations and 30 infections observed in our institution from january 1990 to december 1992, Xanthomonas maltophilia is emerging as an important nosocomial pathogen in immunocompromised patients, especially those receiving broad spectrum antimicrobial antibiotherapy. Distinction between colonisation and infection is often difficult. Xanthomonas maltophilia presents a therapeutic challenge because of its tendency to exhibit multiple resistance.

[Rheumatoid purpura in adults. Apropos of 40 cases]. / Purpura rhumatoïde de l'adulte. A propos de 40 observations.

Fourty cases of Henoch-Schönlein purpura in adults (21 females, 19 males--age 39 years) are reviewed [departments of nephrology (28 cases) and internal medicine (12 cases)]. Dermatological manifestations occur in 39 cases and are similar to those seen in children. Gastrointestinal involvement (23 cases) usually takes the form of abdominal pains or diarrhea; gastrointestinal haemorrhages are rare. These symptoms are less severe than in children in this review as in the literature. Joint manifestations (22 cases) disappear without sequelae. The outcome of the disease depends on the nephropathy, present in 33 patients (82.5%) (all of those of the department of nephrology (100%) and 42% of those of the department of internal medicine). In one third of cases, renal manifestation appears after the onset of the disease (until 24 months). As in the children, haematuria and proteinuria are quasi constant. The renal histopathology is a focal and segmental proliferative glomerulonephritis in 58%, with IgA deposition in the mesangium (16/21 cases). Treatment regimen includes steroïds (10 cases), combination of steroïds with immunosuppressive agents (8 cases), steroïds-immunosuppressive drugs-plasma exchange (2 cases), dapsone (1 case). Of the 26 patients followed for 27 months, 11 are in clinical remission, 7 have persistent proteinuria or hematuria, and 8 have chronic renal failure after 3 months to 13 years. In this review, renal insufficiency, hypertension and young age predict a poor outcome. This severe outcome is probably explained by the fact that most of our patients referred to renal units. Unlike in the children, in which the affection is usually an acute illness, Henoch-Schönlein purpura in the adults seems to be a chronic disease, with prognosis depending on the nephropathy.

[Prognostic role of pregnancy on the course of HIV infection: a retrospective cohort study (1985-92)]. / Rôle pronostique de la grossesse sur l'évolution de l'infection par le VIH: une étude de cohorte rétrospective (1985-1992). Groupe d'épidémiologie clinique du Sida en Aquitaine.

In a hospital-based cohort study of HIV-infected patients, we compare the progression of the disease (occurrence of CDC group IV, death, decline of CD4 below 200/mm3) between 55 women with delivery and 89 matched control HIV positive women with no history of pregnancy. After a mean follow-up of three years, no significant difference was observed between the two groups even after adjustment on prognostic variables.