Residual renal function assessment with cystatin C

Su Jin Kim and coworkers from Korea published an important study on the relationship of residual renal function (RRF) and cystatin in pediatric peritoneal dialysis (PD) patients in this issue of Pediatric Nephrology, both in anuric patients and patients with RRF. Based on a lack of correlation between cystatin C and standard small solute-based dialysis adequacy parameters such as Kt/Vurea but a significant correlation with RRF, the authors concluded that cystatin C may be a good tool to monitor RRF. The editorial reviews the available literature in adults, the different handing between urea and cystatin C, and the determinants of cystatin C clearance in dialysis patients. In adults, cystatin C levels are determined predominantly by RRF, but not exclusively. In anephric hemodialysis and PD patients, there is a correlation with standard weekly Kt/Vurea. Cystatin C levels will also depend on ultrafiltration. Despite these factors that affect cystatin C levels beyond RRF, cystatin C is a useful parameter for monitoring PD patients that may be more closely related to long-term outcomes than small solute adequacy parameters. © 2010 IPNA

Cystatin C reduction ratio depends on normalized blood liters processed and fluid removal during hemodialysis

Background and objectives: A negative correlation between the weekly standard Kt/V (urea) and serum cystatin C level (CysC) in functionally anephric dialysis patients has been previously demonstrated. Our objective was to measure the per dialysis CysC reduction ratio (CCRR) and to compare it with other indices of dialytic functions. Design, setting, participants, & measurements: In a pilot cross-sectional study of 15 functionally anephric patients on conventional high-flux high-efficiency hemodialysis three times per week, CysC levels were drawn pre-, mid-, and postdialysis over 1 week. CCRR was compared with single-pool Kt/V (Sp Kt/V) using urea kinetic modeling, urea reduction ratio (URR), creatinine reduction ratio (CRR), normalized liters processed (LP/kg), and ultrafiltration volume (UF). Normally distributed data (Shapiro-Wilks test) were described as mean ± SD, otherwise as median and interquartile range. Results: The mean pre- and post-CysC levels were 6.0 ± 1.0 and 4.7 ± 1.1 mg/L. The Sp Kt/V and Std Kt/V were 1.5 ± 0.2 and 2.6. The URR, CRR, and CCRR were 70.2% ± 9.0%, 64.5% ± 8.2%, and 26.1% ± 11.8%, respectively. There was no correlation between the CCRR, and the Sp Kt/V, URR, and CRR, whereas CCRR correlated with LP/kg and UF. Multiple regression analysis with these two parameters provided a model that explained 81% of the variance. Conclusions: Our data suggest that normalized liters processed and ultrafiltration volume explain most of the variance of CCRR. Therefore, CCRR may be an excellent method to monitor dialysis efficiency of low molecular weight proteins. Copyright © 2011 by the American Society of Nephrology

Euvolemia in hemodialysis patients: a potentially dangerous goal?

Dialysis patients have high mortality rate and the leading cause of death is cardiovascular disease. Uremic cardiomyopathy differs from that due to conventional atherosclerosis, where cardiovascular changes result in ineffective circulation and lead to tissue ischemia. Modern dialysis has significant limitations with fluid management probably the most challenging. Current evidence suggests that both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. Furthermore, we do not have accurate volume assessment tools. As a result, targeting euvolemia might result in more harm than benefit with conventional hemodialysis therapy. Therefore, it might be time to consider a degree of permissive over-hydration until we have better tools to both determine ideal weight and improve current renal replacement therapy so that the process of achieving it is not so fraught with the current dangers

Big Mother or Small Baby: Which Predicts Hypertension?

According to the Barker hypothesis, intrauterine growth restriction and premature delivery adversely affect cardiovascular health in adult life. The association of childhood hypertension as a cardiovascular risk factor and birth weight has been understudied. In a prospective cohort study, the authors evaluated the effect of birth weight, gestational age, maternal prepregnancy body mass index (BMI), and child BMI z score at the time of enrollment on the systolic and diastolic blood pressure (BP) z score in 3024 (1373 women) consecutive outpatient clinic patients aged 2.05 to 18.58 years. The latest National Health and Nutrition Examination Survey (NHANES III) was used to calculate the age-dependent z scores. The median z scores of BMI (+0.48, range -6.96-6.64), systolic BP (+0.41, range -4.50-6.73), and diastolic BP (+0.34, range -3.15-+6.73) were all significantly greater than the NHANES III reference population. Systolic BP z score did not correlate with birth weight or gestational age, but did correlate with maternal prepregnancy BMI (r=090, P\u3c.0001) and BMI z score (r=209, P\u3c.0001). Diastolic BP z score positively correlated with birth weight (0.037, P=044), gestational age (r=052, P=005), BMI z score(r=106, P\u3c.0001), and maternal prepregnancy BMI (r=062, P=0007). In contrast to what would be expected from the Barker hypothesis, the authors found no negative correlation between BP z score and birth weight or gestational age. This study suggests that a high BMI, a big mom, and a high birth weight are more important risk factors for hypertension during childhood than low birth weight or gestational age. © 2010 Wiley Periodicals, Inc

Big Mother or Small Baby: Which Predicts Hypertension?

According to the Barker hypothesis, intrauterine growth restriction and premature delivery adversely affect cardiovascular health in adult life. The association of childhood hypertension as a cardiovascular risk factor and birth weight has been understudied. In a prospective cohort study, the authors evaluated the effect of birth weight, gestational age, maternal prepregnancy body mass index (BMI), and child BMI z score at the time of enrollment on the systolic and diastolic blood pressure (BP) z score in 3024 (1373 women) consecutive outpatient clinic patients aged 2.05 to 18.58 years. The latest National Health and Nutrition Examination Survey (NHANES III) was used to calculate the age-dependent z scores. The median z scores of BMI (+0.48, range -6.96-6.64), systolic BP (+0.41, range -4.50-6.73), and diastolic BP (+0.34, range -3.15-+6.73) were all significantly greater than the NHANES III reference population. Systolic BP z score did not correlate with birth weight or gestational age, but did correlate with maternal prepregnancy BMI (r=090, P\u3c.0001) and BMI z score (r=209, P\u3c.0001). Diastolic BP z score positively correlated with birth weight (0.037, P=044), gestational age (r=052, P=005), BMI z score(r=106, P\u3c.0001), and maternal prepregnancy BMI (r=062, P=0007). In contrast to what would be expected from the Barker hypothesis, the authors found no negative correlation between BP z score and birth weight or gestational age. This study suggests that a high BMI, a big mom, and a high birth weight are more important risk factors for hypertension during childhood than low birth weight or gestational age. © 2010 Wiley Periodicals, Inc

A Conversation About Current Issues Facing the Global Financial Industry

https://digitalcommons.nyls.edu/filler_institute_events/1014/thumbnail.jp

RDS-21 Face-Gear Surface Durability Tests

Experimental fatigue tests were performed to determine the surface durability life of a face gear in mesh with a tapered spur involute pinion. Twenty-four sets of gears were tested at three load levels: 7200, 8185, and 9075 lb-in face gear torque, and 2190 to 3280 rpm face gear speed. The gears were carburized and ground, shot-peened and vibro-honed, and made from VIM-VAR Pyrowear 53 steel per AMS 6308. The tests produced 17 gear tooth spalling failures and 7 suspensions. For all the failed sets, spalling occurred on at least one tooth of all the pinions. In some cases, the spalling initiated a crack in the pinion teeth which progressed to tooth fracture. Also, spalling occurred on some face gear teeth. The AGMA endurance allowable stress for a tapered spur involute pinion in mesh with a face gear was determined to be 275 ksi for the material tested. For the application of a tapered spur involute pinion in mesh with a face gear, proper face gear shim controlled the desired gear tooth contact pattern while proper pinion shim was an effective way of adjusting backlash without severely affecting the contact pattern