Determination Of Serum Creatinine Research Articles

Parathyroid Hormone: Effects on Glucose Homeostasis and Insulin Sensitivity in Chronic Renal Failure Patients on Regular Hemodialysis

Abstract Objective To look into the relation between parathyroid hormone and abnormal glucose homeostasis in chronic renal failure patients on regular hemodialysis. Methods 41 subjects, with chronic renal failure, and on regular hemodialysis (28 male, 13 female; age range 19–64 years). Full history and clinical examination were taken for every patient. In addition, ten age and sex matched healthy persons were selected randomly as control group. Informed consent was obtained. All patients were investigated to determine serum creatinine, calcium, phosphorus, alkaline phosphatase, parathyroid hormone, fasting glucose, and fasting insulin. Homeostasis module assessment of insulin resistance was calculated as a measure of insulin resistance, Homeostasis module assessment of beta cell was calculated as a measure of pancreatic beta cell function. The uremic patients were classified into two groups: group A included 24 patients with plasma parathyroid hormone levels 450 pg/ml. Results There is a marked increase in fasting insulin level in all patients versus control associated with increased homeostasis module assessment of insulin resistance, an index for insulin resistance. Significant negative correlation is found between parathyroid hormone and fasting insulin and homeostasis module assessment of insulin resistance in uremic patients. Patients with severe hyperparathyroidism have relatively more impaired pancreatic beta cell function in comparison to those with mild hyperparathyroidism. The pulsed dose of intravenous 1-cholecalciferol is associated with low parathormone level and high serum calcium. Conclusion Insulin resistance is a constant feature of chronic renal failure patients under hemodialysis therapy, while secondary hyperparathyroidism is linked negatively to beta cell function. Intermittent pulsed intravenous alphacalcidol is an effective method of lowering high serum parathyroid hormone and is associated with improvement of beta cell function without significant effect on insulin resistance.

Psychological, biochemical and physiological responses of Brazilian soccer players during a training program

Aims of the study The aim of this study is to investigate the behavior of the physiological, biochemical and psychological parameters in Brazilian soccer players during a training program. Materials Fifteen athletes were evaluated at the beginning (T1), in the middle (T2) and at the end (T3) of the training program. On the first day, at 7:30 am, before the blood collecting at rest for the determination of serum creatine kinase (CK), serum creatinine and serum urea, the athletes had their psychological parameters assessed by the profile of mood state questionnaire (POMS). After 90 min, they performed a 250-m sprint. On the second day at 8:30 am, the athletes had their alactic anaerobic performance measured and, after 40 min, they completed the aerobic test. Friedman test was used to verify the behavior of overtraining markers. Results There was a decrease in vigor score in T3 ( p = 0.01) compared with T1 and T2. In T3 ( p = 0.01), the athletes also showed an increase in serum creatinine levels compared to T1. Furthermore, in the same period, we verified a diminishing in the team performance. Conclusion The training program developed between T2 and T3 led to the fall of the vigor score, the increase in serum creatinine concentrations and the diminishing in team performance.

Creatinine Elevation Associated with Nitromethane Exposure: A Marker of Potential Methanol Toxicity

Nitromethane, methanol, and oil are the common components of radio-controlled (R/C) vehicle fuels. Nitromethane can cause a false elevation of serum creatinine concentration as measured by the widely used Jaffe colorimetric method. We gathered data from our poison control system and from previously published case reports to see if a correlation exists between serum methanol concentrations and spuriously elevated serum creatinine concentrations after human exposures to R/C fuel. The California Poison Control System (CPCS) computerized database was queried for all cases of human exposure to R/C vehicle fuel reported between December 1, 2002 and December 1, 2004. Serum creatinine and methanol concentrations were recorded when available, as was the method used to determine serum creatinine. A MEDLINE search was used to obtain previously published cases of human nitromethane exposure associated with falsely elevated creatinine concentrations. During the 2-year period, serum creatinine concentrations were recorded in 7 of 26 R/C fuel exposures (all ingestions), and 6 of these were abnormal (range of 1.9–11.5 mg/dL). In this series, the higher the serum creatinine concentration measured by Jaffe method, the higher the serum methanol concentration. The MEDLINE search yielded data from six previously published case reports on this topic. The data from these case reports seem to follow the trend seen in our case series. These data suggest that a spuriously elevated serum creatinine (by Jaffe method) may have value as an early surrogate marker of methanol poisoning in those who ingest R/C fuel. Also, the degree to which the serum creatinine is elevated may indicate the severity of methanol poisoning.

Does Donor Nephron Mass Have Any Impact on Graft Survival?

Objectives Functioning nephron mass namely, the number of nephrons in the grafted kidney, is one of the nonimmunologic factors that may have some impact on long-term graft survival. The aim of this study was to assess the impact of donor nephron mass on graft outcome in the recipient. Materials and Methods From 1989 to 2005, 1000 renal transplants were performed at our center. The 217 studied cases were followed for an average of 8 years. All patients received grafts from living donors. The weight of the grafted kidney (donor nephron mass) as well as the recipient’s body mass index (BMI) were measured at the time of operation. Nephron mass index (NMI) was defined as the ratio of donor nephron mass to recipient BMI. Associations between variables were tested by logistic regression and Pearson correlation using the SAS system and S-plus statistical software. To evaluate graft function, we determined serum creatinine values, acute rejection episodes and chronic nephropathy. Results Mean NMI was 8.07 ± 0.2 and mean creatinine level was 1.43 ± 0.4 mg/dL. There were 32 cases (14.7%) of acute rejection, who were managed successfully with antithymocyte globulin (ATG) in 28 cases. Four patients lost their grafts. There were 15 cases (7%) of graft loss due to chronic rejection. Using Pearson correlation, we observed no association between NMI and mean serum creatinine level. Logistic regression showed a significant relation between NMI and acute rejection ( P < .05) with an odds ratio of 2.0. There was no significant correlation between NMI and chronic rejection. Conclusions The lower the NMI, the greater the short-term graft loss. However, in the long term, no significant correlation was found between graft survival and NMI. Also, mean creatinine level was not significantly different among patients regardless of NMI.

A Biomarker for Detecting Early Tubulointerstitial Disease and Ischemia in Glomerulonephropathy

Present diagnostic tests such as serum creatinine determination and creatinine clearance are unable to reflect early tubulointerstitial disease. Because a kidney biopsy cannot be performed in every single patient, tubular epithelial function (namely, the fractional excretion of magnesium; FE Mg) that correlates directly with the degree of tubulointerstitial fibrosis would serve this purpose. FE Mg is normal in acute post-streptococcal glomerulonephritis and mesangial proliferative nephrosis with intact tubulointerstitial structure, and is abnormally elevated in nephrosis with focal segmental glomerulosclerosis (FSGS) and in chronic kidney diseases in which kidney biopsies have been obtained. FE Mg is useful in the screening of tubulointerstitial disease in patients when indication for kidney biopsy in not fulfilled, such as diabetic patients or patients with microscopic proteinuria, hematuria, and hypertension. Altered FE Mg is usually associated with a reduction in peritubular capillary flow. There is a linear correlation between FE Mg and peritubular capillary flow, which supports the chronic ischemic injury inducing altered tubular function and tubulointerstitial fibrosis.

Erythropoietin administration protects against functional impairment and cell death after ischaemic renal injury in pigs

To determine whether the administration of erythropoietin at the time of ischaemic renal injury (IRI) inhibits apoptosis, enhances tubular epithelial regeneration and promotes renal functional recovery, as it does in rodent models, in a higher mammalian model. The model of IRI involved unilateral nephrectomy in pigs, followed a week later by renal artery occlusion for 1 h, followed by reperfusion for 5 days. Pigs were randomized to receive erythropoietin 5000 units/kg intravenously at the time of ischaemia, followed by 1000 units/kg subcutaneously daily, or no treatment (six pigs each). Renal function and structure were analysed; blood and urine were collected daily to determine serum creatinine level, blood urea nitrogen, and creatinine clearance. Animals were killed after 5 days to obtain the injured kidneys. The kidneys were examined histologically for evidence of cellular mitosis, apoptosis and necrosis. Erythropoietin significantly abrogated renal dysfunction after IRI compared with controls at 12 h after injury; the mean (sem) creatinine clearance (as a percentage of baseline) for IRI was 68.2 (6)% vs erythropoietin-IRI 94.9 (8.9)% (P = 0.027), although by 36 h this was no longer significant, with values of 73.8 (12.7)% vs 95.9 (12)%, respectively (P = 0.23). Erythropoietin also significantly reduced the amount of cell death on histological analysis after 5 days of reperfusion, with a median (range) for IRI of 5.5 (1-45) vs erythropoietin-IRI of 1.5 (0-4) (P = 0.043). This study confirms the potential clinical applications of erythropoietin as a novel therapeutic agent in patients at risk of IRI.

Inhibition of p38 Mitogen-Activated Protein Kinase and Transforming Growth Factor-β1/Smad Signaling Pathways Modulates the Development of Fibrosis in Adriamycin-Induced Nephropathy

Inflammation and fibrogenesis are the two determinants of the progression of renal fibrosis, the common pathway leading to end-stage renal disease. The p38 mitogen-activated protein kinase (MAPK) and transforming growth factor (TGF)-beta1/Smad signaling pathways play critical roles in inflammation and fibrogenesis, respectively. The present study examined the beneficial renoprotective effect of combination therapy using the p38 MAPK pathway inhibitor (SB203580) and a TGF-beta receptor I (ALK5) inhibitor (ALK5I) in a mouse model of adriamycin (ADR) nephrosis. The p38 MAPK and TGF-beta1/Smad2 signaling pathways were activated in ADR-induced nephropathy in a sequential time course manner. Two weeks after ADR injection, the combined administration of SB203580 (1 mg/kg/24 hours) and ALK5I (1 mg/kg/24 hours) markedly reduced p38 MAPK and Smad2 activities. Moreover, the co-administration of SB203580 and ALK5I to ADR-injected mice resulted in a down-regulation of total and active TGF-beta1 production, reduced myofibroblast accumulation, and decreased expression of collagen type IV and fibronectin. In these mice, retardation in the development of glomerulosclerosis and interstitial fibrosis was observed. In conclusion, although p38 MAPK and TGF-beta1/Smad signaling pathways are distinct they coordinate the progression of renal fibrosis in ADR nephrosis. The co-administration of a p38 MAPK inhibitor and an ALK5 inhibitor may have potential applications in the treatment of renal fibrosis.

Determination of creatinine in human serum and urine by reversed-phase high pressure liquid chromatography

目的 评价以5-氟尿嘧啶(5-Fluorouracil,5-Fu)作内标的反相高压液相色谱(high pressure liquid chromatography ,HPLC)测定血清和尿中肌酐(creatinine)的方法,拟初步推荐其作为肌酐测定的候选参考方法,同时对3种常规肌酐测定试剂进行评定.方法 首先对以5-Fu作内标的反相HPLC测定血清和尿中肌酐的方法进行了方法学评价.进一步以该方法为对比方法,分别采用Jaffe动力学法、酶法、干化学法测定试剂对85份新鲜血清和94份新鲜尿液标本进行测定,对测定结果进行相关和偏差分析.结果 以5-Fu作内标的反相HPLC,其线性范围达2 210 μmol/L,批内变异系数(n=5)＜2.5%,日间变异系数(n=10)＜4.5%,回收率96.3%～102.4%.血清肌酐含量＜150 μmol/L时(n=53),HPLC与各种方法间的相关系数分别为0.931 4、0.942 1、0.928 4.血清肌酐含量＞150 μmol/L时(n=32),HPLC与各种方法间的相关系数分别为0.987 7、0.984 1、0.993 4. 结论 拟推荐以5-Fu作内标的反相HPLC作为肌酐测定的候选参考方法;肌酐酶偶联肌氨酸氧化酶法可作为常规测定方法。

Nephron-Sparing Surgery for Renal Tumours: Acceleration and Facilitation of the Laparoscopic Technique

ObjectivePresent our surgical technique for and experience with laparoscopic partial nephrectomy (LPN) for renal tumours during warm ischaemia. MethodsTwenty-five patients underwent LPN during warm ischaemia via a transperitoneal four-trocar approach. Mean tumour size was 26.2±7.3mm (range: 11–39mm). Sixteen tumours were exophytic, 7 endophytic, and 2 central. The renal vessels were secured by an umbilical tape and occluded by a self-made Rumel tourniquet. Tumours were excised with a cold Endo-shear. The interstitial tissue and collecting system was closed using a running suture secured by two resorbable clips. Parenchymal edges were approximated using a running suture over a haemostatic bolster. The threads were secured by non-resorbable clips. During follow-up, renal function was evaluated by determination of serum creatinine, 99mTc-mercaptoacetyltriglycine scintigraphy, and parenchymal transit time. ResultsMean ischaemia time was 28.9±5.2min (range: 19–40min) and the mean blood loss was 177.4±285.5ml (range: 50–1500ml). No intraoperative complications occurred and no patient needed conversion to open surgery. Surgical margins were negative in all patients. One postoperative surgical-related perirenal haematoma occurred, which was treated conservatively (no transfusions required). None of the patients had a urinary leak. During a mean follow-up of 6.2 mo (range: 1–15 mo), none of the patients had local or port-site recurrence or distant metastasis. Parenchymal transit time was increased in 1 of 10 investigated patients (ischaemia time: 26min), indicating ischaemic parenchymal damage. ConclusionOur technical refinements for LPN during warm ischaemia have widened indications to more complex tumours. The use of clips rather than knot tying made the procedure easier and faster and allowed completion of the suturing during an acceptable warm ischaemia time. The self-made Rumel tourniquet is safe and efficient for vessel control and occlusion. These improvements increase feasibility so that LPN can be used by more laparoscopic urologic surgeons.

New potentiometric sensors for creatinine

Three main types of creatinine potentiometric membrane sensors are described. They are based on the use of dibenzo-30-crown-10 (DB30C10) with potassium tetrakis( p-chlorophenyl)borate type (I), dibenzo-30-crown-10 alone type (II), and potassium tetrakis( p-chlorophenyl)borate alone type (III), incorporating in poly(vinyl chloride) matrix membrane plasticized with either o-nitrophenyl octyl ether or dioctylphthalate. The sensors are used for quantification of creatinine after soaking the membranes in 0.1 M creatinine solution for 2 days. The sensors show almost the same potentiometric response characteristics. Sensor type (I) exhibits Nernstian responses over a concentration range of 5.0 × 10 −5 mol l −1–1.0 × 10 −2 mol l −1 creatinine with cationic slopes of 59.5 ± 0.1 and 60 ± 0.2 mV decade −1 and detection limits of 1.1 × 10 −5 mol l −1 and 8 × 10 −6 mol l −1 creatinine, over the pH range of 3.5–6.5 and 3.5–7.0, for o-NPOE and DOP solvent mediators, respectively. Sensor type (II) displays Nernstian responses over a concentration range of 6.0 × 10 −5 mol l −1–1.0 × 10 −2 mol l −1 creatinine with cationic slopes of 60.0 ± 0.1 and 65.0 ± 0.2 mV decade −1 and detection limits of 1.5 × 10 −5 mol l −1 and 1.4 × 10 −5 mol l −1 creatinine over the pH range of 2.6–6.2 and 2.5–6.0, for o-NPOE and DOP solvent mediators, respectively. Sensor type (III) shows Nernstian responses over a concentration range of 7.0 × 10 −5 mol l −1–1.0 × 10 −2 mol l −1 creatinine with cationic slopes of 60 ± 0.1 and 62.0 ± 0.2 mV decade −1 and detection limits of 2.7 × 10 −5 mol l −1 and 2.0 × 10 −5 mol l −1 creatinine over the pH range of 2.5–6.0, for o-NPOE and DOP solvent mediators, respectively. The response times of the sensors for 10 −3 mol l −1 creatinine solution are instantaneous (4–10 s). The sensors show long-term stability with life span of ∼6 months. The sensors are used for determination of serum creatinine of rats ( Rattus Norvigicus) with mean R.S.D. of 2.62%, and the results agreed well with the Jaffe kinetic method.

Renal function – estimation of glomerular filtration rate

Assessment and follow-up of renal dysfunction is important in the early detection and management of chronic kidney disease. The glomerular filtration rate (GFR) is the most accurate measurement of kidney disease and is reduced before the onset of clinical symptoms. Drawbacks to the measurement of GFR include the high cost and incompatibility with routine laboratory monitoring. Serum creatinine determination is a mainstay in the routine laboratory profile of renal function. The measurement of serum cystatin C has been proposed as a more sensitive marker for GFR. According to National Kidney Foundation-K/DOQ1 clinical guidelines for chronic kidney disease, serum markers should not be used alone to assess GFR. Based on prediction equations, clinical laboratories should report an estimate of GFR, in addition to reporting the serum value. In this article, information is presented on how best to estimate GFR using prediction equations for adults and for children. Using serum creatinine concentration with the Modification of Diet in Renal Disease (MDRD) study equation offers a suitable estimation of GFR in adults. The cystatin C prediction equation with the use of a prepubertal factor seems superior to creatinine-based prediction equations in children of <14 years.

Rat Model of Depending Prostaglandin Renal State: Effect of Ketoprofen

Introduction.The renal prostaglandins (PGs), vasodilators, preserve kidney function during increased activity of the renin-angiotensin system or renal sympathetic nerves (renal PG-dependent state [RPGD]). Ketoprofen (Ket) inhibits cyclooxygenase and, therefore, the synthesis of PGs. The aim of this study was to determine, in the rat, the action of Ket in the renal histology and function in a RPGD state (stress of anesthesia and hemorrhage). Material and Methods. Twenty male Wistar rats, anesthetized with sodium pentobarbital, were randomly divided into two groups: G1—control (n = 10) and G2—Ket (n = 10) submitted to arterial hemorrhage of 30% of volemia (estimated as 6% of body weight) three times (10% each 10 min), 65 min after anesthesia. G2 animals received Ket, 1.5 mg. kg-1, venously, 5 min after anesthesia and 60 min before the first hemorrhage moment (first moment of the study [M1]). Medium arterial pressure (MAP), rectal temperature (T), and heart rate were monitored. G1 and G2 received para-aminohippurate sodium (PAH) and iothalamate sodium (IOT) solutions during the entire experimental time in order to determine clearance of PAH (effective renal plasma flow [ERPF]) and clearance of IOT (glomerular filtration rate [GFR]) without urine collection (determination of blood concentrations of PAH and IOT through the high-performance liquid chromatography), filtration fraction (FF), and renal vascular resistance (RVR). The animals were sacrificed in M3, 30 min after the third hemorrhage (M2) moment, and the kidneys and blood collected during the hemorrhage periods were utilized for histological study and determinations of hematocrit (Ht), serum creatinine (SCr), ERPF, GFR, FF, and RVR, respectively. Results. There were significant reductions of MAP, T, and Ht and a significant increase of SCr. During the experiment, ERPF and GFR did not change, but ERPF was always higher in G1 than in G2. Ket did not alter FF, which increased in G1 over the duration of experiment. The Ket group had significantly higher RVR than the control group. The histology verified that both G1 and G2 were similar for tubular dilation and necrosis, but they were significantly different for tubular degeneration: G1 > G2. Conclusion. The changes observed in kidney histology probably were determined by hemorrhage and hypotension. Ket inhibited the synthesis of PGs and diminished tubular degeneration.

Recommendations for Improving Serum Creatinine Measurement: A Report from the Laboratory Working Group of the National Kidney Disease Education Program

Reliable serum creatinine measurements in glomerular filtration rate (GFR) estimation are critical to ongoing global public health efforts to increase the diagnosis and treatment of chronic kidney disease (CKD). We present an overview of the commonly used methods for the determination of serum creatinine, method limitations, and method performance in conjunction with the development of analytical performance criteria. Available resources for standardization of serum creatinine measurement are discussed, and recommendations for measurement improvement are given. The National Kidney Disease Education Program (NKDEP) Laboratory Working Group reviewed problems related to serum creatinine measurement for estimating GFR and prepared recommendations to standardize and improve creatinine measurement. The NKDEP Laboratory Working Group, in collaboration with international professional organizations, has developed a plan that enables standardization and improved accuracy (trueness) of serum creatinine measurements in clinical laboratories worldwide that includes the use of the estimating equation for GFR based on serum creatinine concentration that was developed from the Modification of Diet in Renal Disease (MDRD) study. The current variability in serum creatinine measurements renders all estimating equations for GFR, including the MDRD Study equation, less accurate in the normal and slightly increased range of serum creatinine concentrations [<133 micromol/L (1.5 mg/dL)], which is the relevant range for detecting CKD [<60 mL.min(-1).(1.73 m2)(-1)]. Many automated routine methods for serum creatinine measurement meet or exceed the required precision; therefore, reduction of analytical bias in creatinine assays is needed. Standardization of calibration does not correct for analytical interferences (nonspecificity bias). The bias and nonspecificity problems associated with some of the routine methods must be addressed.

The importance of standardization of creatinine in the implementation of guidelines and recommendations for CKD: implications for CKD management programmes

In an attempt to reduce late referral and to improve the care of patients with chronic kidney disease (CKD), different organizations have issued guidelines on when to refer patients to the nephrologist. Most suggest referral of patients with a GFR below 60 ml/min/1.73 m2, and demand referral if the GFR is below 30 ml/min/1.73 m2. It is recommended to use the abbreviated MDRD equation to estimate GFR. This formula is, however, sensitive to the creatinine assay methodology. In addition, the impact of the implementation of such guidelines on the nephrology practice has never been evaluated. This study (i) identifies the true burden of CKD in a population and simulates the effects of a 100% implementation of the guidelines on the nephrology work load, and (ii) evaluates the validity of the estimated GFR using the abbreviated MDRD formula when routinely provided. Different laboratories (both hospital and private) in our region were asked to report on all the serum creatinine values performed during the first week of December 2004. If patients had more than one determination, only the lowest serum creatinine value was retained. Patients already known to a nephrology unit were not included. GFR was calculated using the abbreviated MDRD, using the serum creatinine as reported by these laboratories, or after correction to the MDRD-standard using different published equations. 20,108 patients, with a mean age of 53.4+/-16.2 years, 48% females, had at least one serum creatinine determination in the observation period. According to the K/DOQI CKD classification, 20.2, 1.6 and 0.8% of females and 13.3, 1.6 and 0.6% of males were in stage 3, 4 and 5, respectively, when the abbreviated MDRD formula was used with the serum creatinine value as reported by the laboratories. Important differences in classifications were obtained when the different correction formulae for creatinine were applied. According to the current recommendations, this would lead to a mandatory referral of 1650-2400 CKD stage 4 patients per 100 000 inhabitants and a suggested referral of another 4100-15 360 CKD stage 3 patients per 100,000 inhabitants to a nephrology unit. Implementation of the current guidelines for referral of CKD patients to nephrologists would lead to an overload of the nephrology care capacities. Large differences in estimated GFRs with different corrections for serum creatinine are observed, resulting in important CKD classification differences. Standardization of serum creatinine assays is mandatory before guidelines, and especially the routine provision of the estimated GFR by the abbreviated MDRD formula, can be implemented in clinical practice.

The unrecognized prevalence of chronic kidney disease in diabetes

Diabetes mellitus and chronic kidney disease (CKD) are common and exhibit synergistic associations with premature mortality. Current diabetes guidelines in the UK recommend annual urinary albumin and serum creatinine determinations to screen for diabetic kidney disease. The aim of this study was to estimate the burden of CKD in patients with diabetes and examine the ability of serum creatinine and albuminuria to detect clinically meaningful CKD compared with estimated glomerular filtration rate (eGFR). All adults known to have diabetes in primary and secondary care in Salford, UK, alive with independent renal function on 1 January 2004 were included in this observational study (n=7596). Demographic and laboratory parameters were obtained from the Electronic Patient Record. eGFR was determined using the 4-variable modification of diet in renal disease (MDRD) formula. Clinically meaningful CKD was defined as an eGFR <60 ml/min/1.73 m(2). Creatinine and albuminuria were measured in the preceding 2 years in 82.3 and 55.2% of subjects, respectively. In patients with CKD, normoalbuminuria was present in 48.8%, and serum creatinine was normal (<or=120 micromol/l) in 54.7%. An abnormal serum creatinine (>or=120 micromol/l) had a sensitivity and specificity of 45.3 and 100%, respectively, to identify CKD. The combination of abnormal creatinine and albuminuria had an improved performance but still failed to detect a large number with CKD (sensitivity 82.4%, specificity 75.4%). Serum creatinine failed to identify CKD more often in females (OR 8.22, CI 6.56-10.29). Undiagnosed CKD is common in diabetes. Current screening strategies, based on creatinine or albuminuria, fail to identify a considerable number of subjects with CKD. Incorporating eGFR into screening for CKD would identify individuals earlier in the natural history of the disease and enable early effective treatment to delay progression of CKD.

Novel Biomedical Sensors for Flow Injection Potentiometric Determination of Creatinine in Human Serum

Coated-wire (CW) and tubular (Tu) type membrane sensors for creatinine are developed. These consist of creatinine tungstophosphate(CTP), creatinine molybdophosphate (CMP) and creatinine picrolonate (CPC) ion-pair complexes as electroactive materials dispersed in plasticized poly(vinyl chloride) matrix membranes. Electrochemical evaluation of these sensors under static (batch) mode of operation reveals near-Nernstian response with slopes of 62.9, 58.1, and 55.2 mV decade−1 over the concentration range 1×10−2–5.0×10−6, 1×10−2–7.5×10−5, and 1×10−2−3.1×10−5 mol L−1. The lower detection limits are 0.39, 3.49, and 2.20 μg mL−1 creatinine with CTP, CMP and CPC membrane based sensors plasticized with o-NPOE, respectively. Tubular and coated wire CTP membrane sensors are incorporated in flow-through cells and used as detectors for flow injection analysis (FIA) of creatinine. The intrinsic characteristics of the detectors under hydrodynamic mode of operation in a low dispersion manifold are determined and compared with data obtained under static mode of operation. With 10−2 mol L−1 phosphate buffer of pH 4.5 as a carrier solution, the tubular and coated wire CTP detectors exhibit rapid response of 58.9 and 50.7 mV decade−1 over the concentration range 1×10−2–1×10−5 mol L−1 and detection limits of 0.39 μg mL−1 and 0.85 μg mL−1, respectively. Validation of the assay methods with the proposed sensors by measuring the lower detection limit, range, accuracy, precision, repeatability and between-day-variability reveals good performance characteristics confirming applicability for continuous determination of creatinine. The sensors are used for determining creatinine in human blood serum at an input rate of 40 samples per hour. No interferences are caused by creatine, most common anions, cations and organic species normally present in biological fluids. The results favorably compare with data obtained using the standard spectrophotometric method.

Surface-Enhanced Raman Scattering Based Approach for Quantitative Determination of Creatinine in Human Serum

A novel surface-enhanced Raman scattering (SERS) based approach for the quantitative determination of creatinine in human serum is described. Using isotopically labeled (2-13C, 2,3-15N2) creatinine as internal standard, SERS acquires the character of a ratio method that works similar to the well-established isotope dilution techniques. In conjunction with multivariate data analysis, the method was successfully applied for quantifying creatinine at clinically relevant levels and below. A partial least-squares regression model was generated from a set of 87 calibration spectra covering the full range of mole fractions of neat creatinine. The prediction performance of the model was thereafter validated with independent reference samples giving a standard deviation of less than 2%. Finally, a conditioning procedure to prepare real serum samples for SERS-based creatinine analysis was worked out and validated. Measured serum creatinine concentrations are within 3% of the values obtained from gas chromatography/isotope dilution mass spectrometry on the same serum starting material.

Prevalence of chronic kidney disease and anemia among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study: Baseline results

Prevalence of chronic kidney disease and anemia among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study: Baseline results

Acute Kidney Injury, Mortality, Length of Stay, and Costs in Hospitalized Patients

The marginal effects of acute kidney injury on in-hospital mortality, length of stay (LOS), and costs have not been well described. A consecutive sample of 19,982 adults who were admitted to an urban academic medical center, including 9210 who had two or more serum creatinine (SCr) determinations, was evaluated. The presence and degree of acute kidney injury were assessed using absolute and relative increases from baseline to peak SCr concentration during hospitalization. Large increases in SCr concentration were relatively rare (e.g., >or=2.0 mg/dl in 105 [1%] patients), whereas more modest increases in SCr were common (e.g., >or=0.5 mg/dl in 1237 [13%] patients). Modest changes in SCr were significantly associated with mortality, LOS, and costs, even after adjustment for age, gender, admission International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis, severity of illness (diagnosis-related group weight), and chronic kidney disease. For example, an increase in SCr >or=0.5 mg/dl was associated with a 6.5-fold (95% confidence interval 5.0 to 8.5) increase in the odds of death, a 3.5-d increase in LOS, and nearly 7500 dollars in excess hospital costs. Acute kidney injury is associated with significantly increased mortality, LOS, and costs across a broad spectrum of conditions. Moreover, outcomes are related directly to the severity of acute kidney injury, whether characterized by nominal or percentage changes in serum creatinine.

Serum creatinine and cholesterol levels of testicular cancer patients in long‐term follow up

Most patients with advanced testicular cancer can be cured with cisplatin-based chemotherapy. Therefore, the long-term effects of the treatment are clinically important. In the present study, we evaluated the serum creatinine and cholesterol levels of long-term survivors of testicular cancer. Serum creatinine and cholesterol levels were determined in 23 testicular cancer patients who had received cisplatin-based chemotherapy more than 5 years earlier. They were compared with a control group of 16 patients who did not receive chemotherapy. In addition, follow-up data of beyond 10 years after the initial treatment was obtained from 17 patients. We also analysed the trends of both serum creatinine and cholesterol determinations over 10 or more years using a generalized linear model. There was no significant difference in the serum creatinine and cholesterol levels 5 years after the treatment between the chemotherapy and control groups. Analysis using a generalized linear model showed a significant trend toward an increase in serum creatinine in patients who had developed renal dysfunction during chemotherapy (P = 0.0024). The elevation of the serum creatinine level was mainly observed during the first 5 years. In addition, a significant trend toward an increase in serum cholesterol was revealed in both the chemotherapy and control groups. Patients who have developed renal dysfunction during chemotherapy may be at risk of gradually increasing serum creatinine levels even after it has become normal. Although further analysis is needed, we recommend long-term follow up in the survivors of metastatic testicular cancer patients treated with cisplatin-based chemotherapy.