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Background Urine protein assessment is important when glomerular disease or injury is suspected. Normal values of proteinuria already published for preterm newborns suffer from limitation, with small cohorts of patients. This prospective study was conducted to update the urine total protein- and albumin-to-creatinine ratio values. Methods Urine samples were collected from 231 preterm newborns within the first 48 h (D0-1) and/or between 72-120 h of life (D3-4). Total protein, albumin, and creatinine were measured, their distribution and upper-limit values determined. Results At D0-1 and D3-4, respectively, the median for the total protein-to-creatinine ratio were 80 and 107 mg/mmol (upper-limit values 223 and 289 mg/mmol) in the whole studied population, 149 and 214 mg/mmol in children born before 29 weeks of gestational age, 108 and 130 mg/mmol in those born between 29 and 33 weeks, and 61 and 93 mg/mmol in those born after 33 weeks. For the albumin-to-creatinine ratio, the median were 12 and 17 mg/mmol (upper-limit values 65 and 62 mg/mmol) in the whole studied population, 22 and 50 mg/mmol in children born before 29 weeks, 21 mg/mmol in those born between 29 and 33 weeks, and 8 and 12 mg/mmol in those born after 33 weeks. The use of nephrotoxic drugs and mechanical ventilation seems to influence proteinuria and albuminuria values. Conclusions We report distribution of proteinuria- and albuminuria-to-creatinine in preterm newborns, including the upper-limit values. These values should be taken into account in the detection and diagnosis of glomerular disease and/or injury in daily clinical practice., Author(s): Laure Ponthier [sup.1] [sup.2] , Marine Trigolet [sup.2] , Thierry Chianea [sup.3] , Fabienne Mons [sup.2] , Catherine Yardin [sup.1] [sup.4] [sup.5] , Vincent Guigonis [sup.1] [sup.2] , Chahrazed [...]

Author(s): Aya Nawata [sup.1] , Takahiro Morishita [sup.2] , Satoshi Hisano [sup.1] , Kaneyasu Nakagawa [sup.3] , Koichi Kusuhara [sup.2] , Toshiyuki Nakayama [sup.1] Author Affiliations: (1) grid.271052.3, 0000 0004 [...]

DESCRIPTION of CASE A 21-year-old pregnant woman, gravida 2 para 1, presented with hypertension and proteinuria at 20 weeks of gestation. She had a history of pre-eclampsia in her first [...]

A 25-year-old nonsmoking male tire technician presented to the emergency department with a 3-week history of macroscopic hematuria and flank pain. He had previously been feeling well and was taking [...]

The contribution of elevated aldosterone to the pathogenesis of malignant, ANG II-dependent hypertension remains uncertain. Therefore, we examined whether chronic mineralocorticoid receptor blockade attenuates the development of malignant hypertension in transgenic rats (TGRs) with inducible expression of the Ren2 gene [TGR(Cyp1a1Ren2)]. Systolic blood pressure (SBP) was measured by radiotelemetry in male TGRs in three groups: 1) control (n = 9), 2) hypertensives (HT; n = 8), and 3) hypertensives + spironolactone (11 mg x [kg.sup.-1] x day sc; HTS; n = 8). Malignant hypertension was induced with dietary indole-3-carbinol (0.3%) for 10 days. Metabolic measurements were taken at the beginning of the study and at day's 2 and 9. HT exhibited elevated SBP (125 [+ or -] 3 vs. 187 [+ or -] 5 mmHg), plasma renin activity (5 [+ or -] 1 vs. 29 [+ or -] 10 ng ANG I x [ml.sup.-1] x [h.sup.-1]), plasma ANG II (175 [+ or -] 39 vs. 611 [+ or -] 74 fmol/ml), and plasma aldosterone (0.31 [+ or -] 0.04 vs. 5.42 [+ or -] 1.02 nmol/l). Urinary aldosterone excretion increased 5.5-fold by day 2 and an additional 90% by day 9. HT was associated with a 1.8-fold increase in proteinuria by day 9 that was alleviated by treatment with spironolactone (25 [+ or -] 5 vs. 13 [+ or -] 3 mg/day), suggesting that aldosterone contributes to the renal damage observed in malignant hypertension. Urinary Na+ excretion was decreased 76% on day 2, despite a sixfold increase in urinary aldosterone excretion. Decrease in urinary [Na.sup.+] excretion on day 2 in HT suggests that [Na.sup.+] reabsorption was increased in response to the increase in aldosterone; however, the lack of a change in SBP between HT and HTS suggests that mechanisms independent of aldosterone stimulation make a greater contribution to the maintenance of elevated arterial pressure in malignant hypertension in Cyp1a1-Ren2 transgenic rats. angiotensin II; eplerenone; pressure natriuresis; spironolactone

Despite recent discoveries of molecules in podocytes, the mechanisms behind most conditions of proteinuria are still poorly understood. To understand more about this delicate barrier, we studied the functional and morphological effects of mild (15 min) renal ischemia-reperfusion injury (IRI). Renal function was studied in rats in vivo, followed by a more detailed analysis of the glomerular barrier in cooled (8[degrees]C) isolated perfused kidneys (cIPK). Renal blood flow was quickly restored, whereas the glomerular filtration rate remained halved 30 min after IRI. Tubular cell activity was intact as judged from the unaffected Cr-EDTA U/P concentration ratio. In vivo, the fractional clearance (0) for albumin increased 16 times. In rats subjected to cIPK starting 30 min after in vivo IRI, [[theta].sub.albumin] was 15 times and [[theta].sub.Ficoll_36[Angstrom]] 1.8 times higher than in control cIPKs. According to the heterogeneous charged fiber model, IRI reduced the fiber charge density to 38% of control (P < 0.01, n = 7). Morphometric analysis with electron microscopy did not reveal any changes in the podocytes or the glomerular basement membrane (GBM) after IRI, suggesting more subtle changes of the GBM and/or the endothelial glycocalyx. We conclude that mild renal IRI induces formation of reactive oxygen species, massive proteinuria, and loss of charged fibers with no apparent change in morphology. These novel findings stress the importance of other components of the barrier, such as proteoglycans produced by the glomerular cells, and provide a tentative explanation for the mechanisms behind proteinuria in glomerulonephritis, for example. endothelium; basement membrane; glycocalyx; kidney; oxidative stress; podocytes; proteinuria doi:10.1152/ajprenal.00152.2006

Abstract Left renal vein entrapment syndrome (nutcracker syndrome) was documented by magnetic resonance angiography (MRA) as a cause of orthostatic proteinuria in a 14-year-old girl female adolescent. Because of continuous [...]

Abstract This study was designed to characterize proteinuria in children with kidney disease. Random urine samples from 250 pediatric patients were examined by quantitative measures of total protein (pr), albumin [...]

Abstract We report a Caucasian boy of Italian descent with congenital nephrotic syndrome of the Finnish type (NPHS1, CNF, MIM 256300) who developed recurrence of proteinuria and hypoalbuminemia on the [...]

We previously demonstrated the anti-inflammatory effects and renal tissue protection in response to adenosine [A.sub.2A]-receptor ([A.sub.2A]R) activation in acute renal injury. We sought to extend these studies and determine the efficacy of [A.sub.2A]R agonists in a chronic model of renal injury. We hypothesized that [A.sub.2A] agonists mediate renal tissue protection in diabetic nephropathy by reducing glomerular inflammation. Diabetes was induced with single intravenous injection of streptozotocin in Sprague-Dawley rats (50 mg/kg). Increases in urinary albumin excretion (UAE) and plasma creatinine at week 6 in the diabetes group (26- and 6-fold over control, respectively) were markedly reduced by continuous subcutaneous administration of ATL146e (10 ng * kg * [min.sup.-1]), a selective [A.sub.2A] agonist. The increase in UAE in the diabetes group was associated with a significant reduction in the expression of slit diaphragm-associated molecules compared with control (nephrin; P < 0.05 and podocin; P < 0.005) that was reversed by ATL146e treatment. Diabetes led to an increase in urinary excretion of monocyte chemoattractant protein-1 (705% of control), TNF-[alpha] (1,586% of control), IFN-[lambda] (298% of control), kidney fibronectin mRNA (457% of control), and glomerular infiltration of macrophages (764% of control), effects significantly reduced by ATL146e treatment. Mesangial expansion and basement membrane thickness were reduced with ATL146e. To further confirm the selectivity of ATL146e, we used wild-type (WT) or [A.sub.2A] knockout ([A.sub.2A]-KO) mice. Four weeks after diabetes, UAE increased significantly in both WT and [A.sub.2A]-KO diabetic mice (3.0- and 3.3-fold over control). [A.sub.2A] agonist treatment blocked the increase in UAE in WT diabetic mice (P < 0.001), whereas it had no effect on the [A.sub.2A]-KO diabetic mice. These results demonstrate that chronic [A.sub.2A]R activation in diabetic rats 1) ameliorates histological and functional changes in kidneys induced by diabetes and 2) causes reduced inflammation associated with diabetic nephropathy. proteinuria; diabetes; macrophage; kidney; ATL146e

Byline: Ofelia Alvarez (1), Gaston Zilleruelo (2), Dale Wright (1), Brenda Montane (2), Gabriela Lopez-Mitnik (3) Keywords: Children; Glomerular filtration rate; Hemoglobinopathy; Microalbuminuria; Proteinuria Abstract: Patients with sickle cell disease (SCD) may develop kidney dysfunction from childhood. The purpose of this study was to examine the value of serum cystatin C as a marker for glomerular filtration rate (GFR) in children with SCD, as compared to serum creatinine and creatinine clearance (CrCl). Twenty children (ages 9--21, ten males) with SCD with and without albuminuria were studied. The mean serum cystatin for the whole group was 0.89 mg/l (0.5--1.7 mg/l). Mean serum cystatin C was significantly different among the children with proteinuria (n=4), microalbuminuria (n=5), and without albuminuria (n=11) (1.25 mg/l, 0.84 mg/l, and 0.78 mg/l, respectively). The mean GFR derived from serum cystatin was significantly different among these subgroups, becoming abnormal in the proteinuric cohort (63 ml/min per 1.73 m.sup.2), in contrast to 94 for the microalbuminuric, and 103 for the normal subgroups. Serum creatinine (mean: 0.58 mg/dl, range: 0.3--1.1) did not change significantly with the level of albuminuria. Mean CrCl remained normal to increased within the subgroups, (133 ml/min per 1.73 m.sup.2 for those with proteinuria, 144 for those with microalbuminuria, and 163 for the normal subgroup). We conclude that serum cystatin C correlates with the level of albuminuria and may be a reliable method to measure renal function in SCD. Author Affiliation: (1) Division of Pediatric Hematology, University of Miami, 1611 NW 12th Avenue, ACC West, Rm 514, Miami, FL, 33136, USA (2) Division of Pediatric Nephrology, University of Miami, Miami, FL, USA (3) Department of Pediatrics, University of Miami, Miami, FL, USA Article History: Registration Date: 13/01/2006 Received Date: 22/09/2005 Accepted Date: 02/11/2005 Online Date: 21/02/2006

Byline: Shira Koss (1), Ari Perl (1), Adinah Wieder (1), Rachel Frank (1), Suzanne Vento (1), Howard Trachtman (1) Abstract: Proteinuria is utilized to screen for underlying kidney disease and serves as a marker of disease progression. The aim of this study was to test the hypothesis that patients with proteinuria will have a higher frequency of urine dipstick positive for leukocytes as an index of noninfectious renal inflammation. In this retrospective analysis, 1,099 urine specimens were evaluated from 676 patients. Proteinuria was present in 39% of the samples and leukocyturia in 5.1%. The percentage of urines that were dipstick positive for leukocytes was similar in those specimens with or without proteinuria. However, in patients with proteinuria and concomitant leukocyturia, the mean serum creatinine concentration was higher (P=0.003) and the calculated GFR was lower (P=0.01) compared to those without this additional abnormality. These differences were noted despite similar age, gender distribution, and array of underlying diseases in these two groups. Based on these findings, urine dipstick testing for leukocytes as a primary means of screening otherwise healthy children for serious renal disease is of little value. However, in patients with established proteinuria, a positive dipstick result for leukocytes is a simple means of identifying those with more prominent noninfectious renal inflammation, a process which may promote kidney disease progression. This finding may serve as an early marker of the severity of renal injury, regardless of whether the primary process is glomerular or tubular. Author Affiliation: (1) Department of Pediatrics, Division of Nephrology, Schneider Children&apos;s Hospital of North Shore-LIJ Health System, New Hyde Park, New York, NY, USA Article History: Registration Date: 10/01/2006 Received Date: 05/07/2005 Accepted Date: 12/10/2005 Online Date: 01/03/2006

Abstract Predictors of tubular proteinuria (alpha 1-M/crea ratio >10 mg/mmol) were sought in 100 infants of 24-32 weeks' (group 1) and 69 of 34-42 weeks' gestation (group 2). Random spot [...]

Abstract A total of 1,044 school children identified with hematuria and/or proteinuria during a mass school urine screening test were referred to pediatric nephrologists at 13 hospitals in Korea. These [...]

An 80-year-old man was admitted into hospital because he was suffering from shortness of breath, pleural effusions, edema of the legs, history of atrial fibrillation, congestive heart failure, and increasing protienuria. The laboratory studies revealed a nephrotic-range proteinuria and an IgG paraprotein, after which a diagnostic procedure was performed.

Byline: A. Balat (1), M. Cekmen (3), M. Yurekli (4), H. Gulcan (2), O. Kutlu (2), Y. Turkoz (3), S. Yologlu (5) Keywords: Key wordsaAdrenomedullin; Minimal change nephrotic syndrome; Nitric oxide Abstract: Nitric oxide (NO) serves many functions within the kidney, and recent evidence suggests that NO contributes to glomerular injury. Adrenomedullin (AM) is a novel hypotensive peptide originally isolated from human pheochromocytoma. Recent studies showed that plasma AM concentrations correlated with the extent of proteinuria. We have examined the possible role of these two agents by studying plasma and urinary total nitrite (NO.sup.- .sub.2 + NO.sup.- .sub.3) and AM levels in children with minimal change nephrotic syndrome (MCNS). In comparison with healthy controls, children with MCNS had increased urinary nitrite excretion (Aumol/mg urinary creatinine), irrespective of whether the disease was in relapse or remission (3.2+-0.2 in relapse, n=13 1.9+-0.3 in remission, n=12 1.0+-0.2 in controls, n=10, P&lt 0.05). Plasma nitrite levels (Aumol/l) were high in relapse compared with controls (53.2+-8.7 vs. 32+-4.0, P&lt 0.05). Plasma AM levels (pmol/ml) were decreased in relapse (27.6+-1.4 in relapse, 43.3+-1.2 in remission, 41.5+-1.6 in controls, P&lt 0.05). Urinary AM levels (pmol/mg urinary creatinine) were significantly higher in relapse than in remission and in controls (156+-43 in relapse, 56+-18 in remission, 36+-16 in controls, P&lt 0.05). Our data indicate that NO may play a role in mediating the clinical manifestations of MCNS in children. However, changes in AM levels may be the result of heavy proteinuria. Author Affiliation: (1) Gaziantep University, P.K: 34, 27310 Gaziantep, Turkey e-mail: balat@gantep.edu.tr Tel.: +90-342-3603034, Fax: +90-342-3365505, TR (2) Department of Pediatrics, Medical Faculty, Inonu University, Malatya, Turkey, TR (3) Department of Biochemistry, Medical Faculty, Inonu University, Malatya, Turkey, TR (4) Department of Molecular Biology, Medical Faculty, Inonu University, Malatya, Turkey, TR (5) Department of Biostatistics, Medical Faculty, Inonu University, Malatya, Turkey, TR Article note: Received: 20 December 1999 / Revised: 12 June 2000 / Accepted: 15 June 2000

Byline: P. Goodyer (1), V. Langlois (2), D. Geary (2), L. Murray (1), S. Champoux (1), D. Hebert (2) Keywords: Key wordsaCystinosis; Transplantation; Proteinuria; Polyuria; Graft thrombosis Abstract: Because cystinotic patients are polyuric and may have severe proteinuria, each of which is a potential risk factor for graft thrombosis, preemptive transplantation for them is questionable. The objectives of this study were to characterize the changes in urine volume and protein excretion at various stages of cystinosis, determine whether there is serologic evidence of hypercoagulability, and review the clinical experience in renal transplantation in cystinotic children. The records of cystinotic patients followed at the Montreal Children&apos;s Hospital between 1992 and 1998 were reviewed. Urinary volume, protein excretion, and coagulation markers were collected to determine glomerular filtration rate (GFR) &gt 50 ml/min/1.73 m.sup.2, &lt 20 ml/min/1.73 m.sup.2, before and after starting dialysis. In addition, graft failure and graft thrombosis rates were obtained from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database. Urinary volume and protein excretion remained elevated throughout different phases of the disease. Coagulation factors were within normal limits for all patients. In the NAPRTCS database there were four thromboses among the 114 patients transplanted cystinotic patients. All these occurred in cadaveric grafts and only one occurred after preemptive transplantation. Despite polyuria and severe proteinuria, children with cystinosis do not appear to be at an increased risk of graft failure or graft thrombosis. Author Affiliation: (1) Division of Nephrology, Department of Pediatrics, The Montreal Children&apos;s Hospital, 2300 Tupper Street, Montreal, Quebec, Canada e-mail: paul.goodyer@muhc.mcgill.ca, CA (2) Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada, CA Article note: Received: 22 November 1999 / Revised: 5 May 2000 / Accepted: 9 June 2000

Byline: D. Muller (1), D. Greve (3), P. Eggert (3) Keywords: Key wordsaTubular proteinuria; Henoch-Schonlein purpura; Nephritis Abstract: The prognosis of Henoch-Schonlein purpura (HSP) is mainly determined by the involvement of the kidney, but prognostic markers have not been established. To study the extent of tubular involvement in HSP and its relationship to the development of HSP nephritis, we measured the urinary excretion of two tubular marker proteins in 36 children with HSP. After admission, urinary N-acetyl-[beta]-D-glucosaminidase (NAG) was determined in 20 children and [alpha].sub.1-microglobulin ([alpha].sub.1-MG) in 16 children respectively. These values were compared with the biochemical data on admission, 1 month, 6 months, and 12 months later. A total of 198 24-h urine samples from healthy children were used for the establishment of reference data for NAG and [alpha].sub.1-MG (mean+-2 SD). Twenty-one patients had elevated excretion of either NAG (&gt mean+2 SD, n=12) or [alpha].sub.1-MG (&gt mean+2 SD, n=9). The highest values (&gt mean+4 SD) were found in patients with early kidney involvement. Normal values were accompanied by a benign further clinical course. Children with intermediate high values (&gt mean+2 SD, &lt mean+4 SD) developed signs of renal involvement during follow-up. Hence, tubular proteinuria is common during the early stages of HSP. NAG and [alpha].sub.1-MG levels correlate well with the extent of early and late renal involvement. Tubular marker proteins may be prognostic markers for the development of HSP nephritis. Author Affiliation: (1) University of Nijmegen, 162 Cell Physiology, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands e-mail: d.mueller@celfys.kun.nl Tel.: +31-24-3614202, Fax: +31-24-3540525, NL (2) Department of Cell Physiology, University of Nijmegen, The Netherlands, NL (3) Children&apos;s Hospital, University of Kiel, Germany, DE Article note: Received: 21 December 1999 / Revised: 28 February 2000 / Accepted: 27 March 2000

Abstract Congenital nephrotic syndrome is a severe disorder caused by increased permeability of the glomerular capillary leading to massive proteinuria. Typically, this disorder presents in the first three months and [...]

Abstract Although the quantification of protein excretion is valuable for diagnosing and monitoring renal disease, accurate, timed, urine collection entails practical difficulties in children. Several authors have shown that the [...]

* Bence Jones proteinuria, a common clinical manifestation of multiple myeloma, can also be seen in patients with other B-cell-derived neoplasms. Measurement of pretreatment levels is a useful adjunct in the diagnosis and staging of multiple myeloma, whereas serial levels reflect response to therapy. Serum concentrations of [[Beta].sub.2]-microglobulin, a small-molecular-weight protein associated with the major histocompatibility complex class I antigens, are often elevated in hematopoietic neoplasms and are also commonly measured at baseline, before treatment, and serially throughout therapy in patients with multiple myeloma and other lymphoproliferative disorders as a marker of tumor burden. Urinary concentrations, however, are considered an indicator of renal tubular function. High urinary levels are found in tubular proteinuria, a frequent sequela of long-standing multiple myeloma. A case is described in which a high urinary concentration of [[Beta].sub.2]-microglobulin interfered with Bence Jones protein quantification by electrophoresis studies. (Arch Pathol Lab Med. 2001;125:555-557), Bence Jones proteinuria, found in 60% or more of patients with multiple myeloma (MM) and less often in patients with other B-cell--derived malignancies, such as solitary plasmacytoma, Waldenstrom macroglobulinemia, and [...]