24-hr Urine Research Articles

Determinants and within-person variability of urinary cadmium concentrations among women in northern California.

Background: Cadmium (Cd) is a toxic metal associated with increased morbidity and mortality. Urinary Cd (U-Cd) concentration is considered a biomarker of long-term exposure.Objectives: Our objectives were to evaluate the within-person correlation among repeat samples and to identify predictors of U-Cd concentrations.Methods: U-Cd concentrations (micrograms per liter) were measured in 24-hr urine samples collected from 296 women enrolled in the California Teachers Study in 2000 and a second 24-hr sample collected 3–9 months later from 141 of the participants. Lifestyle and sociodemographic characteristics were obtained via questionnaires. The Total Diet Study database was used to quantify dietary cadmium intake based on a food frequency questionnaire. We estimated environmental cadmium emissions near participants’ residences using a geographic information system.Results: The geometric mean U-Cd concentration was 0.27 µg/L and the range was 0.1–3.6 µg/L. The intraclass correlation among repeat samples from an individual was 0.50. The use of a single 24-hr urine specimen to characterize Cd exposure in a case–control study would result in an observed odds ratio of 1.4 for a true odds ratio of 2.0. U-Cd concentration increased with creatinine, age, and lifetime pack-years of smoking among ever smokers or lifetime intensity-years of passive smoking among nonsmokers, whereas it decreased with greater alcohol consumption and number of previous pregnancies. These factors explained 42–44% of the variability in U-Cd concentrations.Conclusion: U-Cd levels varied with several individual characteristics, and a single measurement of U-Cd in a 24-hr sample did not accurately reflect medium- to long-term body burden.

Lower potassium intake is associated with increased wave reflection in young healthy males

Increased potassium intake has been shown to lower blood pressure (BP) even in the presence of high sodium consumption however the role of dietary potassium on vascular function has received less attention. The objective of this study was to evaluate the relationship between habitual intake of sodium (Na) and potassium (K) and measures of arterial stiffness and wave reflection. 20 healthy males (24±0.7 yrs; systolic BP 121±3; diastolic BP 64±2 mmHg) recorded their dietary intake for 3 days and collected their 24‐hr urine on the 3rd day. Carotid‐femoral pulse wave velocity (PWV) and the synthesis of a central aortic pressure waveform (by radial artery applanation tonometry and generalized transfer function) were performed. Aortic augmentation index (AI), an index of wave reflection, was calculated from the aortic pressure waveform. Subjects consumed an average of 2,492 kcals, 4,212 mg Na, and 2,967 mg of K. Average urinary Na/K excretion ratio was 2.69±0.3. An inverse relationship between AI and K excretion was found (r= −0.3122; p<0.001) while no relationship was noted with Na excretion (r= − 0.005; p>;0.05). AI positively correlated with the Na/K excretion ratio (r= 0.153; p<0.05). PWV did not correlate with either nutrient or the Na/K excretion ratio (p>;0.05). These data suggest that lower potassium intakes are associated with stiffer arteries in young healthy males. Supported by R01 HL 104106.

Interactions of Hypoxia inducible factor (HIF)‐1α and Peroxisome proliferator‐activated receptor (PPAR) α in the protection against ischemia/reperfusion injury in the rat kidney

In response to reduced oxygen availability, important cellular and molecular adaptive changes occur in living organisms. Hypoxia‐inducible factor (HIF) is a major adaptive mechanism and prolyl hydroxylase‐binding domain proteins (PHD) is its most important negative regulator. However, peroxisome proliferator‐activated receptor (PPARα), a nuclear transcription factor is activated in response to hypoxia/HIF‐1α and regulates many of the downstream target genes. This study tested the hypothesis that inhibition of prolyl hydroxylase domain (PHD) would confer greater protection against ischemia by a mechanism involving PPARα activation. Rats were subjected to ischemia/reperfusion (I/R) for 48 hours with or without L‐mimosine (L), a PHD inhibitor, fenofibrate, a PPARα ligand, MK886, a PPARα inhbitior. Renal blood flow (RBF; laser doppler flowmetry) recovered to 93±8%, 56±7% (p<0.001) and 87±10% (p<0.001) in control, ischemic and L‐treated groups, respectively. Coincident with these changes, serum uric acid decreased by 41±6% (p<0.05) in I/R group versus 26±3% (p<0.05) following L‐ treatment. Compared to controls, serum nitric oxide decreased by 33±3% (p<0.05) in ischemic group while L treatment abolished the effect of ischemia (P<0.05). Similarly, 24hr urine volume increased by 100±13% (p < 0.001) in I/R and this was abolished by L (3%±0). 24‐hour urinary protein excretion increased 5‐fold in I/R group but was attenuated to a 2‐fold increase in L‐treated (p<0.05) group. Fenofibrate protected rats from the effects of I/R while MK886 blunted its effect. These findings suggest that stabilization of HIF‐1α following inhibition of PHD protects against I/R in the rat kidney and that PPARα contributes to these effects.

Influence of Growth Rate on Nitrogen Balance in Adolescent Sprint Athletes

This study aimed to estimate nitrogen balance and protein requirements in adolescent sprint athletes as a function of growth rate and physical development. Sixty adolescent sprint athletes were followed up biannually over a 2-yr period. Individual growth curves and age at peak height velocity were determined. Skeletal muscle mass (SMM) was estimated based on anthropometric measurements and fat mass was estimated by underwater densitometry. Seven-day diet and physical activity diaries were completed to estimate energy balance and protein intake. Nitrogen analysis of 24-hr urine samples collected on 1 weekday and 1 weekend day allowed calculation of nitrogen balance. Body height, weight, and SMM increased throughout the study period in both genders. Mean protein intakes were between 1.4 and 1.6 g kg-1 day-1 in both genders. A protein intake of 1.46 g kg-1 day-1 in girls and 1.35 g kg-1 day-1 in boys was needed to yield a positive nitrogen balance. This did not differ between participants during and after their growth spurt. None of the growth parameters was significantly related to nitrogen balance. It can be concluded that a mean protein intake around 1.5 g kg-1 day-1 was sufficient to stay in a positive nitrogen balance, even during periods of peak growth. Therefore, protein intake should not be enhanced in peak periods of linear or muscular growth.

Comparison of Urinary Protein: Creatinine Index and Dipsticks for Detection of Microproteinuria in Diabetes Mellitus Patients

Proteinuria has been recognized as one of the earliest signs of renal function deterioration in Diabetes mellitus. Proteinuria occurs due to alterations in the glomerular permeability and later, due to a failure in the reabsorption of filtered protein by the tubular cells. Normally, most of the healthy adults excrete 20-150 mg of protein in urine over 24 hours. To find out the normal urinary Protein Creatinine Index (PCI) in healthy subjects, to compare the urinary PCI of diabetic patients with that of healthy subjects and to compare the urinary PCI with dipsticks for the detection of microproteinuria. This study was conducted on 28 type 2 Diabetes mellitus patients and 40 age and sex matched healthy controls. Freshly collected urine samples were tested qualitatively for the presence of proteinuria by Heller's test, the sulfosalicylic acid test, heat-coagulation tests and urine dipsticks. Later on, the results were compared by performing a quantitative analysis of the protein in the spot urine samples by the sulfosalicylic acid method. A quantitative analysis of creatinine was done by the modified Jaffe's test. The PCI was calculated for each of the participant in the study. The Mean and Standard Deviation (SD) of the PCI was calculated and it was compared between the two groups. The normal range of the PCI which was established in this study was 60 to 220. Significantly higher amount of proteins were found to be excreted in urine in diabetic patients (25.37 ± 12.51 mg/dl) as compared to those in normal subjects (8.93 ± 3.54 mg/dl). On comparison of the PCI between the controls and the diabetic subjects, it was found to be significantly elevated in the Diabetes mellitus patients (controls = 114.65 ±47.97 and in the diabetic patients =373.04 ± 98.53) (p < 0.001). The PCI of a random urine sample can provide a very useful, simple and convenient method for the quantitative assessment of proteinuria, to judge the extent of kidney damage and for avoiding the drawbacks of the 24 - hr urine collections.

Disruption of the endothelin A receptor in the nephron causes mild fluid volume expansion

BackgroundEndothelin, via endothelin A receptors (ETA), exerts multiple pathologic effects that contribute to disease pathogenesis throughout the body. ETA antagonists ameliorate many experimental diseases and have been extensively utilized in clinical trials. The utility of ETA blockers has been greatly limited, however, by fluid retention, sometimes leading to heart failure or death. To begin to examine this issue, the effect of genetic disruption of ETA in the nephron on blood pressure and salt handling was determined.MethodsMice were generated with doxycycline-inducible nephron-specific ETA deletion using Pax8-rtTA and LC-1 transgenes on the background of homozygous loxP-flanked ETA alleles. Arterial pressure, Na metabolism and measures of body fluid volume status (hematocrit and impedance plethysmography) were assessed.ResultsAbsence of nephron ETA did not alter arterial pressure whether mice were ingesting a normal or high Na diet. Nephron ETA disruption did not detectably affect 24 hr Na excretion or urine volume regardless of Na intake. However, mice with nephron ETA knockout that were fed a high Na diet had mild fluid retention as evidenced by an increase in body weight and a fall in hematocrit.ConclusionsGenetic deletion of nephron ETA causes very modest fluid retention that does not alter arterial pressure. Nephron ETA, under normal conditions, likely do not play a major role in regulation of Na excretion or systemic hemodynamics.

Immunoglobulin Heavy/Light Chain Measurements During Monitoring Provide Prognostic Information of Relapse After Therapy in Myeloma Patients

AbstractAbstract ▪3964▪This icon denotes a clinically relevant abstract Introduction:Monitoring multiple myeloma (MM) patients is required to help guide therapy and assess response. Currently the most commonly employed tests to monitor MM patients include serum protein electrophoresis (SPEP), immunofixation (IFE), 24hr urine and serum free light chain (FLC) analysis. Whilst electrophoretic tests are adequate for IgG MM, they may be inadequate for IgA MM where the monoclonal immunoglobulin co-migrates with other serum proteins (∼60% of cases). Recently the inclusion of FLC testing to identify patients in stringent complete response (sCR) has been recommended. Novel nephelometric reagents have become available that can quantify IgA kappa and IgA lambda immunoglobulins (HLC) in serum. Here we assess the use of these tests at maximum response to detect residual disease and comment on the prognostic value of sCR.Patients, materials and methods:196 IgA MM patient samples recruited from the MRC IX trial were assessed at maximum response. Briefly, patients were randomised on to intensive (I: induction therapy with CVAD or CTD followed by high-dose melphalan and ASCT) and non-intensive (NI: clodronate or zoledronic with MP or CTDa) arms. Median age was 59 years (range: 37–71) and 74 years (range: 65–89) for patients in the I and NI arms, respectively. 31% patients in the I arm and 39% in the NI arm presented with stage III disease. Samples were taken 3 months after autologous stem cell transplant or maximum response and analysed nephelometrically using serum FLC and HLC immunoassays. Ratios for both FLC and HLC were compared to normal ranges (FLC normal ratio= 0.256–1.65, IgAkappa/IgAlambda normal ratio=0.8–2.04). Additionally, isotype-matched immunoparesis was described as <0.48 g/L IgAkappa and <0.36g/L IgAlambda. Results were compared to SPEP, IFE and total immunoglobulin assays (where immunoparesis was described as <6g/L IgG and <0.4g/L IgM). 2-year progression free survival (PFS) was determined using Kaplan Meier analysis (SPSS v 19.0). Results:3 months post-therapy, patient responses were: I arm: progressive disease (PD): n=1(<1%); minimal response (MR): n=1(<1%); partial response (PR): n=10(8%); very good partial response (VGPR): n=35(29%); complete response (CR): n=13(11%); sCR: n=58(48%); for two patients no data was available; NI arm: progressive disease (PD): n=3(4%); stable disease (SD): n=5(7%); MR: n=10(13%); PR: n=31(41%); VGPR: n=16(21%); CR: n=11(15%). Within the 2-year follow up, 41% patients in the I arm and 46% in the NI arm relapsed. Median PFS was not significantly different between the two arms (not reached v 7 months, p=0.65).Response (3VGPR) was not associated with PFS in either arm (I, p=0.717; NI, p=0.236). By contrast, achievement of a sCR (p=0.013) was significantly associated with longer PFS in the I arm and tended towards significance in the NI arm (p=0.063). An abnormal HLC ratio was associated with shorter PFS in both arms (I, p=0.002; NI, p=0.032). In all patients achieving a 3VGPR, an abnormal HLC ratio was associated with shorter PFS (p>0.0001). Similarly, in patients achieving a 3CR an abnormal HLC ratio was also associated with shorter PFS (p=0.04). Furthermore, patients achieving a CR where both FLC and HLC ratios were normal had a significantly longer PFS than those with an abnormal FLC or HLC ratio (median PFS not reached v 18 months, p=0.007). Isotype-matched immunoparesis was associated with shorter PFS in all patients achieving a CR (p=0.061). By contrast, systemic immunoparesis of either IgG or IgM immunoglobulins were not associated with PFS (p=0.525 and p=0.964, respectively). Discussion:Novel therapies have dramatically improved MM patient outcomes, however improvements in the assessment of those outcomes has not followed a similar trajectory. Here we present data suggesting immunoglobulin HLC ratios may be better markers of residual disease than electrophoretic methods. In addition a response category based on normalisation of both FLC and HLC ratios may be more valuable than sCR. Finally, the identification of isotype matched immune reconstitution as a marker of outcome suggests a preferential suppression of immunoglobulin production not previously reported. Conclusion:Normalisation of the FLC and HLC ratio at maximum response is a better assessment of disease than IFE. Further work is required to validate these results and to assess FLC and HLC ratios against multi-parametric flow cytometry. Disclosures:Young:Binding Site: Employment.

Excellent Intermediate-Term Results after Renal Transplantation from Brain-Dead Donors with Acute Kidney Injury

Background: Organ shortage remains the leading obstacle in kidney transplantation. Whether organs from brain-dead donors with acute kidney injury (AKI) should be accepted for transplantation is still a matter of debate. Methods: Centre-based, matched cohort study of 33 renal transplant patients who had received a renal allograft by way of rescue allocation from a donor with AKI prior to organ procurement. 65 kidney transplants devoid of AKI in the donor and performed in each case directly beforehand and thereafter served as controls. Results: All donors with AKI were classified according to the RIFLE criteria: Of these, 3 donors (9.1%) fulfilled level “Risk”, 18 (54.6%) level “Injury”, and 12 (36.4%) level “Failure”. Mean serum-creatinine was 2.41±0.88 mg/dL at time of procurement and 1.06±0.32 mg/dL on admission, respectively. AKI donors had a lower 24hr urine production (3.6 L [IQR 1.2-4.1 L] vs. 4.1 L, [IQR 3.1-5.3 L], P=0.009), were many times exposed to noradrenaline (31/33 [93.9%] vs. 47/65 [72.3%], P=0.02) and/or adrenaline (5/33 [15.2%] vs. 1/65 [1.5%], P=0.02), and had more often undergone cardio-pulmonary resuscitation (11/33 [33.3%] vs. 7/65 [10.8%] P=0.01). Recipient and transplant characteristics, including age, gender, waiting-time, cold ischemia, and immunosuppressive therapy were very similar excepting a more favourable HLA-match in control patients (P=0.01). Hemodialysis posttransplant was more frequently used in AKI recipients (14/33 [42.4%] vs. 18/65 [27.7%], P=0.17). While significant elevations in serum creatinine were noted in these patients until 10 days after transplantation, this difference lost statistical significance by day 14. One year graft survival was very similar comparing the groups (93.6% [95%CI 76.8%-98.4%] vs. 90.3% [95%CI 0.79.6%-95.5%], log rank P=0.58).Figure: [Trajectories of serum creatinine levels]Conclusions: Kidneys from donors with AKI can be transplanted with an excellent intermediate prognosis and should not be discarded.

Excellent Intermediate-Term Results after Renal Transplantation from Brain-Dead Donors with Acute Kidney Injury

Background: Organ shortage remains the leading obstacle in kidney transplantation. Whether organs from brain-dead donors with acute kidney injury (AKI) should be accepted for transplantation is still a matter of debate. Methods: Centre-based, matched cohort study of 33 renal transplant patients who had received a renal allograft by way of rescue allocation from a donor with AKI prior to organ procurement. 65 kidney transplants devoid of AKI in the donor and performed in each case directly beforehand and thereafter served as controls. Results: All donors with AKI were classified according to the RIFLE criteria: Of these, 3 donors (9.1%) fulfilled level “Risk”, 18 (54.6%) level “Injury”, and 12 (36.4%) level “Failure”. Mean serum-creatinine was 2.41±0.88 mg/dL at time of procurement and 1.06±0.32 mg/dL on admission, respectively. AKI donors had a lower 24hr urine production (3.6 L [IQR 1.2-4.1 L] vs. 4.1 L, [IQR 3.1-5.3 L], P=0.009), were many times exposed to noradrenaline (31/33 [93.9%] vs. 47/65 [72.3%], P=0.02) and/or adrenaline (5/33 [15.2%] vs. 1/65 [1.5%], P=0.02), and had more often undergone cardio-pulmonary resuscitation (11/33 [33.3%] vs. 7/65 [10.8%] P=0.01). Recipient and transplant characteristics, including age, gender, waiting-time, cold ischemia, and immunosuppressive therapy were very similar excepting a more favourable HLA-match in control patients (P=0.01). Hemodialysis posttransplant was more frequently used in AKI recipients (14/33 [42.4%] vs. 18/65 [27.7%], P=0.17). While significant elevations in serum creatinine were noted in these patients until 10 days after transplantation, this difference lost statistical significance by day 14. One year graft survival was very similar comparing the groups (93.6% [95%CI 76.8%-98.4%] vs. 90.3% [95%CI 0.79.6%-95.5%], log rank P=0.58).Figure: [Trajectories of serum creatinine levels]Conclusions: Kidneys from donors with AKI can be transplanted with an excellent intermediate prognosis and should not be discarded.

Variability of Organophosphorous Pesticide Metabolite Levels in Spot and 24-hr Urine Samples Collected from Young Children during 1 Week

Background: Dialkyl phosphate (DAP) metabolites in spot urine samples are frequently used to characterize children’s exposures to organophosphorous (OP) pesticides. However, variable exposure and short biological half-lives of OP pesticides could result in highly variable measurements, leading to exposure misclassification.Objective: We examined within- and between-child variability in DAP metabolites in urine samples collected during 1 week.Methods: We collected spot urine samples over 7 consecutive days from 25 children (3–6 years of age). On two of the days, we collected 24-hr voids. We assessed the reproducibility of urinary DAP metabolite concentrations and evaluated the sensitivity and specificity of spot urine samples as predictors of high (top 20%) or elevated (top 40%) weekly average DAP metabolite concentrations.Results: Within-child variance exceeded between-child variance by a factor of two to eight, depending on metabolite grouping. Although total DAP concentrations in single spot urine samples were moderately to strongly associated with concentrations in same-day 24-hr samples (r ≈ 0.6–0.8, p < 0.01), concentrations in spot samples collected > 1 day apart and in 24-hr samples collected 3 days apart were weakly correlated (r ≈ –0.21 to 0.38). Single spot samples predicted high (top 20%) and elevated (top 40%) full-week average total DAP excretion with only moderate sensitivity (≈ 0.52 and ≈ 0.67, respectively) but relatively high specificity (≈ 0.88 and ≈ 0.78, respectively).Conclusions: The high variability we observed in children’s DAP metabolite concentrations suggests that single-day urine samples provide only a brief snapshot of exposure. Sensitivity analyses suggest that classification of cumulative OP exposure based on spot samples is prone to type 2 classification errors.

High creatinine clearance in critically ill patients with community-acquired acute infectious meningitis

BackgroundA high dose of anti-infective agents is recommended when treating infectious meningitis. High creatinine clearance (CrCl) may affect the pharmacokinetic / pharmacodynamic relationships of anti-infective drugs eliminated by the kidneys. We recorded the incidence of high CrCl in intensive care unit (ICU) patients admitted with meningitis and assessed the diagnostic accuracy of two common methods used to identify high CrCl.MethodsObservational study performed in consecutive patients admitted with community-acquired acute infectious meningitis (defined by >7 white blood cells/mm3 in cerebral spinal fluid) between January 2006 and December 2009 to one medical ICU. During the first 7 days following ICU admission, CrCl was measured from 24-hr urine samples (24-hr-UV/P creatinine) and estimated according to Cockcroft-Gault formula and the simplified Modification of Diet in Renal Disease (MDRD) equation. High CrCl was defined as CrCl >140 ml/min/1.73 m2 by 24-hr-UV/P creatinine. Diagnostic accuracy was performed with ROC curves analysis.ResultsThirty two patients were included. High CrCl was present in 8 patients (25%) on ICU admission and in 15 patients (47%) during the first 7 ICU days for a median duration of 3 (1-4) days. For the Cockcroft-Gault formula, the best threshold to predict high CrCl was 101 ml/min/1.73 m2 (sensitivity: 0.96, specificity: 0.75, AUC = 0.90 ± 0.03) with a negative likelihood ratio of 0.06. For the simplified MDRD equation, the best threshold to predict high CrCl was 108 ml/min/1.73 m2 (sensitivity: 0.91, specificity: 0.80, AUC = 0.88 ± 0.03) with a negative likelihood ratio of 0.11. There was no difference between the estimated methods in the diagnostic accuracy of identifying high CrCl (p = 0.30).ConclusionsHigh CrCl is frequently observed in ICU patients admitted with community-acquired acute infectious meningitis. The estimated methods of CrCl could be used as a screening tool to identify high CrCl.

Abstract 605: Calcitonin Gene Related Peptide (cgrp) And Its Role In Cardiovascular And Autonomic Regulation

Calcitonin gene related peptide (CGRP) is the most potent microvascular vasodilator known. It exerts effects centrally as well as in the gastrointestinal, respiratory and endocrine system. However, its role in cardiovascular regulation remains controversial. We studied the hemodynamic and autonomic function in CGRP knockout (KO) mice. Blood pressure (BP), heart rate (HR) and activity level were assessed at least one week after mice were implanted with telemeters. Ten CGRP KO and ten wild type (WT) mice (3-4month old) were used in this study. After the recording period, 24-hr urine and blood were collected for assessment of catecholamine and their metabolites. To study the baroreflex sensitivity, phenylephrine and sodium nitroprusside were administered in an acute study with seven mice from each group. We found higher blood pressure at rest during daytime in the CGRP KO mice (102.4 ± 1.652mmHg, vs. 110.5 ± 3.242mmKg, p = 0.039), though not in 24-hr mean arterial pressure (MAP) (105.0 ± 1.789mmHg, vs. 112.1 ± 3.123mmHg, p = 0.05). There was no difference in HR in the two groups (KO: 566.4 ± 12.09; WT: 581.9 ± 8.544, p = 0.31). Norepinephrine was greatly elevated in both plasma and 24-hr urine in KO mice (in urine: KO: 956.7 ± 90.65 pg/ml, WT: 618.1 ± 46.15pg/ml, p = 0.004; in plasma: KO: 2505 ± 596.3pg/ml, n=6, WT: 1168 ± 98.05 pg/ml, p = 0.04). Baroreflex sensitivity was higher in the KO mice (KO: 3.217 ± 0.6852 ms/mmHg, n=7, WT: 1.398 ± 0.2583 ms/mmHg, n=7, p=0.03). The activities level was slightly lower in the KO mice (KO: 6.717 ± 1.059 counts/min, WT: 10.59 ± 1.787 counts/min p = 0.08). However, KO mice that were 6-8 month old were heavier compared to WT mice of the same age (KO: 30.65 ± 0.6009 g, n=17, WT: 27.89 ± 0.6345 g, n=17, p = 0.004). While CGRP might seem to contribute less to the physiological regulation of blood pressure in young adult mice due to their better baroreflex function, it likely contributes to blood pressure and sympathetic activation in older mice. Therefore, further study in BP, HR and metabolic syndromes in old CGRP KO mice is required.

Abstract 78: Chronic Intrarenal Ghrelin Receptor Antagonism Delays the Onset and Attenuates the Magnitude of High Fat Diet-Induced Hypertension in Dahl Salt-Sensitive Rats

Excess weight gain contributes up to 65% of the risk of primary hypertension in developed countries and the increase in blood pressure (BP) in response to high-fat diet (HFD) is preceded by significant reductions in renal tubular sodium (Na + ) excretion. In normal rats, direct renal infusion of ghrelin, the most potent appetite-stimulating hormone in the body, increases distal nephron-dependent Na + reabsorption via activation of ghrelin receptors (GR) in the kidney. The present study seeks to determine the role of intrarenal GR-mediated Na + reabsorption in HFD-induced hypertension. Dahl salt-sensitive rats (DSS) received standard diet (STD, 10% kcal fat, N=6) or HFD (42% kcal fat, N=14) for 6 weeks (WK). Prior to the initiation of the study, all DSS underwent a uninephrectomy and osmotic minipump implantation for chronic renal interstitial (RI) delivery of 5% dextrose in water (D 5 W, 0.25 μL/hr x 28-day) or selective GR antagonist [D-Lys-3]-GHRP-6 (D-LYS, Tocris, IC 50 =0.9 μmol/L, 5 mg over 28-day) into the remaining kidney. At the end of the study, pump patency and security of RI delivery was confirmed via direct visualization. DSS with D 5 W pumps (N=7) demonstrated a significant increase in mean systolic BP (SBP) after 2 WK on HFD (135±4.4 mmHg vs. 118±2.7 mmHg at baseline, *P&lt;0.05) with a mean SBP of 150±3.9 mmHg by WK 6 (***P&lt;0.001 from baseline). However, DSS with D-LYS pumps (N=7) for chronic RI GR antagonism during HFD failed to become hypertensive until WK 4 (134±3.9 mmHg vs. 121±3.3 mmHg at baseline, *P&lt;0.05) and the mean SBP achieved at WK 6 was only 139±3.6 mmHg ( + P&lt;0.05 compared to HFD D 5 W pump rats). DSS fed a STD failed to develop significant hypertension and served as a time control group. HFD rats with D 5 W pumps demonstrated significantly reduced 24-hr urine Na + excretion prior to the onset of hypertension at WK 2 (0.94±0.15 vs. 1.35±0.09 μmol/min at baseline, *P&lt;0.05). The reduction in Na + excretion failed to occur in DSS with a D-LYS pump (1.24 ±0.12 vs. 1.29±0.09 μmol/min at baseline, P=NS) despite exposure to the same HFD and identical weight gain. These results indicate that increased intrarenal GR-mediated Na + reabsorption contributes to the development of HFD-induced hypertension, offering a novel therapeutic target for obesity-induced hypertension.

Abstract 28: Increased Blood Pressure Response to Salt Intake in Hypertensive G Carriers of The NEDD4L SNP rs4149601

Introduction: Individual blood pressure (BP) response to high salt intake varies from minimal to substantial and is largely genetically determined. More than 50% of hypertensive patients are salt sensitive (SS) and respond to high salt intake by increasing their BP compared to only 10% in the normotensive population. ENaC is involved in sodium transport in the distal nephrons of the kidney as well as in the CNS in the choroid plexus and hypothalamic neurons. In turn, ENaC is controlled by the E3 ubiquitin ligase protein - NEDD4L. The functional NEDD4L SNP rs4149601 (G/A) influences the ability of NEDD4L to regulate ENaC expression and is associated with high blood pressure and salt sensitivity. We hypothesize that NEDD4L rs4149601 genotype is an independent predictor of BP response to salt intake in hypertensives. Methods: Daytime BP was measured using 24hr ABPM in 191 young (&lt;60 years old) Caucasian hypertensives (BP ≥130/85 mmHg). 24hr urine Na and K + , blood Na + and K + , and BMI were collected. Patient genotyping for the rs4149601 (G/A) SNP was done using TaqMan MGB probe based RT PCR. Linear regression analyzed (SAS Software) the influence of urine Na + , urine K + , blood K + ,blood Na + , age, gender, and BMI on blood pressure traits. Results: In hypertensive rs4149601 G carriers (n=169), systolic BP (SBP) varied significantly with salt intake (p=0.0088) while diastolic BP did not (p=0.7198). An SBP increase of 2.34 mmHg per 50 mmol Na was observed when urine Na alone is considered. Age (p=0.0002) and blood K + (p=0.0466) were also significant determinants of SBP in patients with the G allele. Only blood K + was a significant predictor of diastolic BP (DBP) in hypertensive G allele carriers. None of the factors tested influenced either SBP or DBP in hypertensive patients who are carriers of the A allele. Conclusion: The functional NEDD4L rs4149601 SNP influences individual daytime BP response to salt intake. This result supports the hypothesis that NEDD4L rs4149601 G carriers with intact C2 domain express higher levels of ENaC and therefore are more sensitive to salt intake. Thus, NEDD4L rs4149601 polymorphism genotyping may allow for identification of hypertensive individuals who will benefit to a greater extent from reducing the amount of salt in their diet.

Abstract 624: Chronic High Fat Diet Increases Sodium Reabsorption and αENaC Expression Prior to the Onset of Hypertension in Dahl Salt-Sensitive Rats

An increase in distal nephron-dependent sodium (Na+) reabsorption plays a primary role in the development of obesity-induced hypertension. However, the specific Na+ transporter involved in this process is unknown. The present studies were undertaken to determine the role of the epithelial Na+ channel (ENaC) in the development of high fat-diet (HFD)-induced hypertension. Given that human obesity-induced hypertension is largely salt-sensitive, we chose to expose Dahl salt-sensitive (DSS) rats to either a chronic HFD (42% kcal from fat, normal salt, 0.25%, N=7)) or standard diet (STD, 10% kcal from fat, normal salt, 0.25%, N=7), measure blood pressures (BP) telemetrically, and collect 24 hr urine for Na+ each week, for 4 weeks. In a separate group of DSS rats, we isolated cortical collecting ducts for determination of αENaC protein expression at baseline, 1 week, and 4 weeks following STD or HFD. Telemetric systolic blood pressure (SBP) values increased significantly (P&lt;0.05) from a baseline value of 118±2.7 mmHg to 135±4.4 mmHg after just 2 weeks on the HFD, and to 146.9±2.6 mmHg after 4 weeks (P&lt;0.01). SBPs did not change in DSS rats on STD for the entire 4 weeks. Prior to the increase in BP, 24 hr urine Na+ excretion significantly decreased in DSS rats on HFD compared to STD (0.94±0.15 μmol/min vs. 1.35±0.09, P&lt;0.05). Furthermore, compared to baseline, αENaC protein levels significantly increased after 1 week of HFD [0.93±0.13 and 0.51±0.02 densitometric units (DU) respectively, P&lt;0.01], but not after 1 week of STD (0.46±0.02 DU). Following 4 weeks of HFD, αENaC protein levels remained significantly elevated (0.66±0.05 DU; P&lt;0.05) compared to baseline. These results suggest that increased cortical collecting duct αENaC protein expression may contribute to the reduction in Na+ excretion that initiates the hypertensive cascade in HFD-induced hypertension.

Spot Urine Protein Measurements

Proteinuria and albuminuria are important markers of allograft pathology and are associated with graft loss and cardiovascular disease. Traditionally, these have been quantified using a 24-hr urine collection, but spot urine measurements (albumin-creatinine and protein-creatinine ratios) have become popular because of convenience. Aside from tests of correlation, there has been little evaluation of these measurements in kidney transplantation. To further assess the value of albumin-creatinine and protein-creatinine ratios, we measured protein-creatinine ratio and 24-hr urine protein excretion (n=192) and albumin-creatinine ratio and 24-hr urine albumin excretion (n=189) in stable renal transplant patients. Bias (measured minus estimated value), precision, and accuracy was calculated. For the protein-creatinine ratio, percent bias ranged from 12% to 21%, and the accuracy (within 30% of 24-hr collection) was only 47% to 56% depending on the degree of proteinuria. For the albumin-creatinine ratio, percent bias ranged from 9% to 21%, and the accuracy (within 30%) ranged from 38% to 80% depending on the degree of albuminuria. There was no statistical difference between accuracy of protein-creatinine and albumin-creatinine ratios. The ability of the albumin-creatinine and protein-creatinine ratios to accurately predict 24-hr albumin and protein excretion is modest. Given the similar accuracy of both measurements, either protein-creatinine ratio or albumin-creatinine ratio can be used for monitoring protein excretion. However, given the limitations of both the albumin-creatinine ratio and protein-creatinine ratio in this population, a 24-hr urine collection should be considered before making major clinical decisions (e.g., biopsy) based on the presence of proteinuria.

Isolated juxtapapillary haemangioma

AbstractPurpose To report a case of a juxtapapillary retinal capillary haemangiomaMethods A 21‐year‐old lady was referred from her optician with a six month history of blurred vision in her right eye. She was otherwise fit and well and did not take any regular medication. She had experienced occasional migraines in the last few years. She had no significant family history of note. On presentation, her visual acuity was 6/6 in both eyes. She had evidence of right optic disc swelling with some telangiectatic changes in a peripapillary distribution. In addition there were significant hard exudates temporal to the macula. A fundus fluorescein angiogram and OCT were undertaken which were consistent with a juxtapapillary capillary haemangioma. Although she had no systemic symptoms suggestive of Von Hippel‐Lindau (VHL) syndrome, we referred her to a clinical geneticist to initiate investigations to evaluate this, as retinal haemangiomas are a frequent presenting feature of VHL; although they can be an isolated disorder. She underwent an abdominal and pelvic USS which was reported as normal, MRI of the head was reported as revealing no features suggestive of VHL disease, FBC, U&amp;Es were also normal, 24 hr urine collection was normal for adrenaline, nor‐adrenaline and dopamine.Results Sixteen months after her first visit, her vision dropped to 6/12. OCT imaging demonstrated increasing macular oedema and exudation over the fovea. It was decided that the best option for treatment was intravitreal avastin, in combination with photodynamic therapy.Conclusion Combined anti‐VEGF therapy and PDT are a treatment option for juxtapapillary capillary haemangioma; although prognosis is often poor.

EFFECT OF FLAVANOID RICH FRACTION OF CITRUS MEDICA LINN. (RUTACEA) ON ETHYLENE GLYCOL INDUCED UROLITHIASIS IN RATS.

Ethylene glycol (0.75% v/v p.o. in drinking water; 28 days) induced urolithiasis was used to study the protective effect of  flavanoid rich fraction of Citrus medica Linn. (FFCM) at three dose level (320 µg/kg; 380 µg/kg; 440 µg/kg- 28 days; p.o.) in male wistar albino rats (250-300g; n=6/group). Cystone (750 mg/kg; p.o.) was used as standard drug. After completion of treatment period of 28 days,  24 hr urine sample and blood were collected. Various physical parameters like body weight, diuresis, pH, kidneys weight (wet and dry) were measured. Various stone forming inhibitors (Magnesium and Citrate) and promoters (Oxalate, Calcium, Phosphate, Uric acid and Urea)  were analysed in urine, serum and kidney homogenate. Renal function test (BUN and Creatinine clearance), antioxidant parameters (MDA and Catalase) and crystalluria were also evaluated. FFCM at all dose level significantly prevented EG induced changes in calcium, inorganic phosphate, uric acid, oxalate, urea, citrate, magnesium level; creatinine clearance and oxidative stress. FFCM possess anti-lithiatic activity in experimentally induced urolithiatic model (Ethylene glycol model), that can be attributed to its diuretic action, decrease in promoters and increase in inhibitors level &amp; antioxidant potential. Key words: Urolithiasis, Citrus medica Linn., Calcium oxalate, Ethylene glycol.

A COMPARISON OF PROGRESSION OF CHRONIC RENAL FAILURE: LOW DOSE VS STANDARD DOSE KETOACIDS

Purpose: It has been documented that a low protein diet (LPD) with ketoacid analogues (one ketosteril® /5 kg) can postpone dialysis therapy in chronic kidney disease. The purpose of the study was to compare the effects of residual renal function preservation between low dose (one ketosteril® /10 kg) and standard dose (one ketosteril® /5 kg) ketoacid analogues. Methods: The study was a prospective, open-label, group-comparison design. The duration was 6 months. Patients were enrolled in two hospitals when the serum Cr more than 6 mg/dL (CKD stage 4,5). Then the enrolled patients were randomized to three groups, LPD, LPDK1 (LPD + standard dose ketosteril®), LPDK2 (LPD + low dose ketosteril®). The definition of LPD was 0.6-0.8 gm of protein/kg body weight/day. The comparable variables were routine hemogram, bio-chemistry data, iPTH, reciprocal Cr (1/Cr), (eGFR), UN/Cr levels in 24-hr urine (UUN/UCr). The measurements were performed in baseline and 6th month. Results: Demographics of patients were LPD: 22 (M/F:10/12), 49.5 y/o, BMI 21.5±3.3; LPDK1:21 (8/13), 53.6 y/o, BMI 22.7±3.5; LPDK2:37 (15/22), 62 y/o (p: Conclusions: The 6-month observation study showed low dose ketoacid analogues combined with LPD had a beneficial effect to slow down renal function deterioration in CKD stage 4,5. However, the slope of 1/Cr levels in low dose ketoacid analogues was less than that in standard dose ketoacid analogues.

Effec Of Low Protein Diet On Chronic Renal Failure Due To Autosomal Dominant Polycystic Kidney Disease

There are few reports about therapeutic effects of low protein diet on the progression of chronic renal failure due to autosomal dominant polycystic kidney disease (ADPKD), although the disease is common.The annual incidence rate for end-stage renal disease caused by ADPKD is around 6 per million.In this retrospective study in one center, ten chronic renal failure patients due to ADPKD with creatinine clearnce of 17.0±3.3 mL/min /1.73 m 2 and serum creatinine (Cr) level of 4.4±0.7 mg/dL were studied for 40 months after the introduction of severe low protein diet (SLPD) (0.48±0.03 g/kgBW/day) without supplementation of essential amino acids or keto-analogues. Dietary protein intake was estimated by urea appearance rate from 24hr urine sample according to Mitch-Maroni's formula. The results clearly showed that ▵1/Cr/month(×10 −3 ) was significantly suppressed from 5.8±0.9 to 2.0±0.6 following the introduction of SLPD ( p p