Biomedical subjects
Publications and source records attributed to Gabriel Choukroun.
We describe here the first case of Nocardia nova spondylodiscitis accompanied by a psoas abscess due to spreading from pulmonary nocardiosis. Nocardia was cultured from all affected sites. After 1 year of an appropriate antimicrobial therapy and a surgical drainage of the abscess that was required, the patient's clinical condition had improved.
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The 2003 guidelines for the management of hyperparathyroidism in chronic kidney disease compiled by the Kidney Disease Outcomes Quality Initiative of the National Kidney Foundation (NKF-K/DOQI) were formulated on the basis of work published up until 2001. Since then, new drugs (e.g. calcimimetics and lanthanum carbonate) have become available, and others (e.g. sevelamer, nicotinamide and paricalcitol) have been more stringently clinically evaluated. Because of these advancements, a reappraisal of the 2003 guidelines is justified. In this article we critically review the following recommendations of the NKF-K/DOQI: (i) routine use of 1.25 mmol/l (5.0 mg/dl) dialysate calcium and 1 alphaOH-vitamin D derivatives; (ii) limitation of the maximal daily dose of calcium-based oral phosphate binders to 1.5 g of elemental calcium; and (iii) not correcting vitamin D insufficiency in dialysis patients.
Calcimimetics suppress the secretion of parathyroid hormone by sensitizing the parathyroid calcium receptor to serum calcium. Cinacalcet (Sensipar/Mimpara), Amgen Inc., Thousand Oaks, CA), the first-in-class calcimimetic agent approved for treatment of secondary hyperparathyroidism in dialysis patients, is, in association with higher dose of a calcium-based oral phosphate binder, a well-tolerated and effective alternative to standard treatments such as vitamin D derivatives in association with a non-calcium-based oral phosphate binder. Here, we present an overview of evidence in support of this assertion. We extend our discussion to encompass other indications for calcimimetics -- secondary hyperparathyroidism in predialysis chronic kidney disease patients, hypercalcemic hyperparathyroidism in renal transplant recipients, primary hyperparathyroidism, and hypercalcemia associated with parathyroid carcinoma -- as well as providing guidance on optimal usage of this drug.
Addition of interleukin-2 receptor antagonist (IL-2RA) induction to calcineurin inhibitor (CNI)-based regimens reduces biopsy-proven acute rejection by 30-40%. IL-2RA induction facilitates early withdrawal of steroids, and supports the safe use of reduced-exposure CNI or delayed CNI introduction. IL-2RAs and rabbit antithymocyte globulin (Thymoglobulin) show comparable efficacy in patients at standard or low immunologic risk, but the adverse event profiles of lymphocyte-depleting agents are less favorable. IL-2RAs, uniquely, provide effective immunosuppression with similar tolerability to placebo.
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Nephrolithiasis still remains a too frequent - and under-appreciated - cause of end-stage renal disease (ESRD), and this is all the most unfortunate since such an untoward course is now preventable in most cases. Among 1391 patients who started maintenance dialysis at Necker hospital between 1989 and 2000, nephrolithiasis was identified as the cause of ESRD in 45 of them, an overall prevalence of 3.2%. Infection stones accounted for 42.2% of cases, calcium stones for 26.7%, uric acid stones for 17.8% and hereditary diseases for 13.3%. The proportion of nephrolithiasis-associated ESRD declined from 4.7% to 2.2% from the 1989-1991 to the 1998-2000 period, as a result of the decreased incidence of ESRD in patients with infection and calcium nephrolithiasis. Based on our observations and on published reports, it emerges that most cases of nephrolithiasis-associated ESRD were due to sub-optimal management (especially in the case of infection or cystine stones) or to late (or erroneous) etiologic diagnosis, precluding early institution of appropriate therapeutic measures. In particular, several patients with primary hyperoxaluria or 2,8-dihydroxyadeninuria were diagnosed while already on dialysis or after unsuccessful kidney transplantation, due to wrong initial diagnosis. In conclusion, thanks to recent advances in diagnosis and management of stone formers, ESRD should now be prevented in the great majority of patients, at the condition of early etiologic diagnosis based on accurate morphoconstitutional analysis of calculi and metabolic evaluation, and early implementation of appropriate preventive medical treatment.
BACKGROUND/AIMS: Alpha-galactosidase A (alpha-GLA) deficiency (Fabry disease) is an X-linked lysosomal storage disorder. The associated visceral complications are progressive and multiorgan; renal involvement is common, usually leading to end-stage renal failure (ESRF). The reported benefits of specific enzyme replacement therapy (ERT) indicate the importance of screening for Fabry disease in high-risk populations, as this approach should make it possible to identify other family members with little or no clinical features of the disease, and for them to be considered for early preventive treatment. METHODS: We screened for Fabry disease in 106 patients on hemodialysis in our hospital-based hemodialysis unit. We did this by measuring alpha-GLA enzyme activity in blood leukocytes taken from each patient and we then carried out gene analysis when indicated. RESULTS: We were able to discover 1 patient with low residual alpha-GLA activity (a prevalence of 0.94%). Alpha-GLA gene analysis identified a point mutation within the coding region producing a N215S amino acid substitution in the protein. Among the relatives of this index case, molecular testing found 7 family members with the same N215S alpha-GLA mutation. Of these, 3 had reduced alpha-GLA activity and clinical features of Fabry disease, and for which ERT was subsequently given. CONCLUSION: Screening for Fabry disease is simple and although the yield is small, it is potentially significant and of possible benefit to the relatives of affected cases in this 'at-risk' ESRF population, many of who do not have a clear renal diagnosis.
Renal sinus lipomatosis consists of abnormal fatty proliferation of the renal sinus, hilus, and perirenal spaces. Its pathogenesis is unknown, although it is generally associated with aging, renal atrophy, and long-standing chronic inflammation or urinary tract infection. Although this condition is rare, it may be important to recognize it in renal transplant recipients. We describe three cases of replacement kidney lipomatosis that occurred after cadaveric renal transplantation and discuss the possible differential diagnosis of this condition.
Anemia is a common complication in patients with chronic kidney diseases (CKD), including transplanted patients. Recent studies have found a prevalence of anemia of about 30%, whereas less than 10% of these patients received recombinant human erythropoietin. Factors explaining this high incidence of anemia in renal transplant recipients include delayed and impaired graft function and use of drugs inhibiting the action of angiotensin II and preventing rejection. Like in CKD patients, chronic anemia may impact on the cardiovascular system and finally on the high mortality of these patients. Recent data suggest also that anemia may be a factor of progression of renal dysfunction in kidney transplant recipients. A French randomized multicenter study was designed to answer this question.
Erythropoiesis-stimulating agents have dramatically changed the management of renal anaemia since their introduction almost 20 years ago. However, optimal dosing route and frequency are still a matter of debate. Intravenous application of recombinant human erythropoietin should be limited to haemodialysis patients and must be given three times weekly, as any reduction to this dosing frequency leads to a major increase in dose requirements. Administering recombinant human erythropoietin-beta once weekly via the subcutaneous route is effective. If conversion from the subcutaneous to the intravenous route is required, dose requirements for recombinant human erythropoietin therapy remain a subject of discussion.
BACKGROUND: The contribution of nephrolithiasis-related end-stage renal disease (ESRD) to patients requiring renal replacement therapy has never been specifically evaluated. METHODS: Of the entire cohort of 1,391 consecutive patients who started maintenance dialysis therapy at our nephrology department between January 1989 and December 2000, a total of 45 patients (21 men) had renal stone disease as the cause of ESRD and constitute the study material. Type and cause of renal stone disease was determined in the 45 patients, as well as the change in prevalence of nephrolithiasis-related ESRD with time during this 12-year period. RESULTS: The overall proportion of nephrolithiasis-related ESRD was 3.2%. Infection (struvite) stones accounted for 42.2%; calcium stones, 26.7%; uric acid nephrolithiasis, 17.8%; and hereditary diseases (including primary hyperoxaluria type 1 and cystinuria), 13.3% of cases. Women were predominant among patients with infection and calcium stones, whereas men were predominant among patients with uric acid or hereditary stone disease. The proportion of patients with nephrolithiasis-related ESRD decreased from 4.7% in the triennial period 1989 to 1991 to 2.2% in the most recent period, 1998 to 2000 ( P = 0.07). This tendency to a decreasing prevalence mainly was caused by a rarefaction of infection and calcium stones with time, whereas frequencies of uric acid and hereditary stone disease remained essentially unchanged. CONCLUSION: Severe forms of nephrolithiasis remain an underestimated cause of potentially avoidable ESRD and need for renal replacement therapy. These findings highlight the crucial importance of accurate stone analysis and metabolic evaluation to provide early diagnosis and proper therapy for conditions that may lead to ESRD through recurrent stone formation and/or parenchymal crystal infiltration.
Positive pressure ventilation with large tidal volumes has been shown to cause release of cytokines, including interleukin (IL)-8. The mechanisms regulating lung stretch-induced cytokine production are unclear. We hypothesized that stretch-induced IL-8 production is dependent on the activation of the mitogen-activated protein kinases, c-Jun NH2-terminal kinases (JNK), p38, and/or extracellular signal-regulated kinase (ERK) 1/2. We exposed A549 cells, a type II-like alveolar epithelial cell line, to cyclic stretch at 20 cycles/min for 5 min-2 h. Cyclic stretch induced IL-8 protein production, IL-8 mRNA expression, and JNK activation, but only transient activation of p38 and ERK1/2. Inhibition of stretch-induced JNK activation by adenovirus-mediated gene transfer of stress-activated protein kinase (SEK-1), a dominant-negative mutant of SEK-1, the immediate upstream activator of the JNKs, and pharmacological JNK inhibitor II SP-600125 blocked IL-8 mRNA expression and attenuated IL-8 production. Inhibition of p38 and ERK1/2 did not affect stretch-induced IL-8 production. Stretch-induced activation NF-kappaB and activator protein (AP)-1 was blocked by NF-kappaB inhibitor and JNK inhibitor, respectively. An NF-IL-6 site was not essential for cyclic stretch-induced IL-8 promoter activity. Stretch also induced NF-kappaB-inducing kinase (NIK) activation, and inhibition of NF-kappaB attenuated IL-8 mRNA expression and IL-8 production. We conclude that stretch-induced transcriptional regulation of IL-8 mRNA and IL-8 production was via activation of AP-1 and NF-kappaB and was dependent on JNK and NIK activation, respectively.
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OBJECTIVES: To determine the degree of anaemia corresponding to the decreasing levels of renal function in patients with chronic renal failure (CRF) and not yet on dialysis, and to assess the indications for treatment with recombinant erythropoeitin (epoetin). METHODS: We studied the relationship between haemoglobin (Hb) concentration and creatinine clearance (Ccr) in 403 consecutive patients with CRF regularly monitored in nephrology consultations between January 1 and June 30, 1999, and who received appropriate iron and vitamin supplementation. These patients were then followed-up until June 30, 2000 or until maintenance dialysis was initiated. RESULTS: There was a significant and close correlation between the degree of anaemia and renal dysfunction. An Hb value<11 g/dl (corresponding to the present threshold for the indication of epoetin) was observed in 62% of patients with creatinine levels>400 micromol/l and in 58% when Ccr was<20 ml/mn/1.73 m2. Whatever the level of CRF, the degree of anaemia was higher in the women than in the men. Among the 123 patients who had to start maintenance dialysis during the observation period, 85 (69%) were treated with epoetin before dialysis was started. CONCLUSION: In patients with CRF, clinically symptomatic anaemia is more frequent than imagined, and early treatment is required. Regular monitoring of Hb and iron levels is mandatory in order to allow patients to benefit from timely initiation of epoetin and thus prevent the development of disabling asthenia and other deleterious consequences of anaemia.
The A3243G mutation of the mitochondrial tRNA(Leu) gene has been recently reported in rare patients with focal and segmental glomerulosclerosis (FSGS). However, the full spectrum of systemic and kidney manifestations in adults presenting with this mutation remains poorly defined. Assessment of renal and nonrenal manifestations was performed in nine patients with A3243G mutation and prominent kidney disease diagnosed in adulthood. At first renal evaluation, median age was 35 years. Renal lesions consisted of FSGS (n = 2), tubulointerstitial nephropathy (n = 3), or bilateral enlarged cystic kidneys (n = 1). All but one patient exhibited extrarenal manifestations: deafness (8 of 9) requiring hearing aid in half the cases, diabetes mellitus (3 of 9), neuromuscular involvement (2 of 9), hypertrophic cardiomyopathy (1 of 9), and macular dystrophy (1 of 9). After a median follow-up of 5 yr, five patients progressed to end-stage renal disease between the ages of 15 and 51 years, four being successfully transplanted. Similarly, extrarenal manifestations progressed since all patients had deafness and diabetes (including three posttransplants), while half had neuromuscular, cardiac, or retinal involvement. In the adult patients with A3243G mutation and renal involvement, preexisting deafness is almost consistently found. While FSGS remains the most typical lesion, tubulointerstitial nephropathy or bilateral, enlarged cystic kidneys may also be encountered. In most cases, diabetes mellitus, macular dystrophy, hypertrophic cardiomyopathy, or neuromuscular features occur later in the course of the disease. The severity of the clinical course is heterogeneous, with end-stage renal failure being reached between the second and sixth decades. Renal transplantation may be offered to these patients, despite a high incidence of steroid-induced diabetes mellitus.