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Background: The Modification of Diet in Renal Disease (MDRD) Study equation underestimates measured glomerular filtration rate (GFR) at levels>60 mL/min/1.73 m2, with variable accuracy among subgroups; consequently, estimated GFR (eGFR)>or=60 mL/min/1.73 m2 is not reported by clinical laboratories. Here, performance of a more accurate GFR-estimating equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, is reported by level of GFR and clinical characteristics.Study Design: Test of diagnostic accuracy.Setting& Participants: Pooled data set of 3,896 people from 16 studies with measured GFR (not used for the development of either equation). Subgroups were defined by eGFR, age, sex, race, diabetes, prior solid-organ transplant, and body mass index.Index Tests: eGFR from the CKD-EPI and MDRD Study equations and standardized serum creatinine.Reference Test: Measured GFR using urinary or plasma clearance of exogenous filtration markers.Results: Mean measured GFR was 68+/-36 (SD) mL/min/1.73 m2. For eGFR<30 mL/min/1.73 m2, both equations have similar bias (median difference compared with measured GFR). For eGFR of 30-59 mL/min/1.73 m2, bias was decreased from 4.9 to 2.1 mL/min/1.73 m2 (57% improvement). For eGFR of 60-89 mL/min/1.73 m2, bias was decreased from 11.9 to 4.2 mL/min/1.73 m2 (61% improvement). For eGFR of 90-119 mL/min/1.73 m2, bias was decreased from 10.0 to 1.9 mL/min/1.73 m2 (75% improvement). Similar or improved performance was noted for most subgroups with eGFR<90 mL/min/1.73 m2, other than body mass index<20 kg/m2, with greater variation noted for some subgroups with eGFR>or=90 mL/min/1.73 m2.Limitations: Limited number of elderly people and racial and ethnic minorities with measured GFR.Conclusions: The CKD-EPI equation is more accurate than the MDRD Study equation overall and across most subgroups. In contrast to the MDRD Study equation, eGFR>or=60 mL/min/1.73 m2 can be reported using the CKD-EPI equation. [ABSTRACT FROM AUTHOR]

Background: Serum cystatin C was proposed as a potential replacement for serum creatinine in glomerular filtration rate (GFR) estimation. We report the development and evaluation of GFR-estimating equations using serum cystatin C alone and serum cystatin C, serum creatinine, or both with demographic variables.Study Design: Test of diagnostic accuracy.Setting& Participants: Participants screened for 3 chronic kidney disease (CKD) studies in the United States (n = 2,980) and a clinical population in Paris, France (n = 438).Reference Test: Measured GFR (mGFR).Index Test: Estimated GFR using the 4 new equations based on serum cystatin C alone, serum cystatin C, serum creatinine, or both with age, sex, and race. New equations were developed by using linear regression with log GFR as the outcome in two thirds of data from US studies. Internal validation was performed in the remaining one third of data from US CKD studies; external validation was performed in the Paris study.Measurements: GFR was measured by using urinary clearance of iodine-125-iothalamate in the US studies and chromium-51-EDTA in the Paris study. Serum cystatin C was measured by using Dade-Behring assay, standardized serum creatinine values were used.Results: Mean mGFR, serum creatinine, and serum cystatin C values were 48 mL/min/1.73 m(2) (5th to 95th percentile, 15 to 95), 2.1 mg/dL, and 1.8 mg/L, respectively. For the new equations, coefficients for age, sex, and race were significant in the equation with serum cystatin C, but 2- to 4-fold smaller than in the equation with serum creatinine. Measures of performance in new equations were consistent across the development and internal and external validation data sets. Percentages of estimated GFR within 30% of mGFR for equations based on serum cystatin C alone, serum cystatin C, serum creatinine, or both levels with age, sex, and race were 81%, 83%, 85%, and 89%, respectively. The equation using serum cystatin C level alone yields estimates with small biases in age, sex, and race subgroups, which are improved in equations including these variables.Limitations: Study population composed mainly of patients with CKD.Conclusions: Serum cystatin C level alone provides GFR estimates that are nearly as accurate as serum creatinine level adjusted for age, sex, and race, thus providing an alternative GFR estimate that is not linked to muscle mass. An equation including serum cystatin C level in combination with serum creatinine level, age, sex, and race provides the most accurate estimates. [ABSTRACT FROM AUTHOR]

Biventricular pacing (BiV) is emerging for patients with dilated cardiomyopathy (DCM) and asynchrony. We measured basal asynchrony and early resynchronization by radionuclide angioscintigraphy (RNA) in order to predict long-term evolution of ventricular function after BiV. Thirty-four patients (NYHA Class III-IV,65.4 +/- 11 years) with large QRS(179 +/- 18 ms)were implanted with BiV and studied by RNA before (D0), at day 8 (D8), and during follow-up(20 +/- 7 months). We calculated left and right ejection fractions, the interventricular dyssynchrony (TRVLV), and the apicobasal dyssynchrony (Tab). LVEF improved from 20.2 +/- 8.1%(D0) to27.1%+/- 12.6%(follow-up,P < 0.003 vs D0) and RVEF from 28.6%+/- 13%(D0) to 34.3 +/- 11.5%(follow-up,P < 0.03 vs D0). Inter- (DeltaTRVLV) and intraventricular resynchronization was immediate and remained stable: TRVLV decreased from 68.3 +/- 38 ms(D0) to 13.4 +/- 48.5 ms(D8) and1.8 +/- 39.2 ms(follow-up,P < 0.0001 vs D0); and Tab from 45.8 +/- 64.1 msto-18 +/- 68(D8) and-28.3 +/- 53.6 ms(follow-up,P < 0.0001 vs D0). Early inter- and intraventricular resynchronization (DeltaTab) at D8 were related to late LVEF and RVEF improvement. Together, an LVEF > 15% and a significant interventricular dyssynchrony (TRVLV > 60 ms) at D0 have a sensitivity of 79% and a positive predictive value of 83% to predict an improvement of LVEF superior to 5% at follow-up. In DCM patients, BiV resynchronizes ventricles early and in the long-term, while RVEF and LVEF improve progressively. Patients with large electromechanical dyssynchrony benefit most from BiV. [ABSTRACT FROM AUTHOR]

The rising demand for efficient cooling technologies is a strong driver of extensive research in this area. This trend is particularly strong in turbines and microprocessors technology. Presented study is focused on the jet impingement cooling concept, which is used in various configurations for many years. The potential of the heat sink shape modification is not yet fully explored. Available literature suggests that average Nusselt number can be improved by more than 10% by adding conical shape in the stagnation region. This refers to the axisymmetric case where cold-water jet impinges the surface of heated aluminium. Presented results are based on 2D axisymmetric thermal-FSI (Fluid-Solid Interaction) model, which was validated against the experiment. The objective of the presented analysis is to determine the correlation between cooling effectiveness (Nusselt number) and chosen examples of concave and convex shapes located in the jet stagnation area.

BACKGROUND Current equations for estimated glomerular filtration rate (eGFR) that use serum creatinine or cystatin C incorporate age, sex, and race to estimate measured GFR. However, race in eGFR equations is a social and not a biologic construct. METHODS We developed new eGFR equations without race using data from two development data sets: 10 studies (8254 participants, 31.5% Black) for serum creatinine and 13 studies (5352 participants, 39.7% Black) for both serum creatinine and cystatin C. In a validation data set of 12 studies (4050 participants, 14.3% Black), we compared the accuracy of new eGFR equations to measured GFR. We projected the prevalence of chronic kidney disease (CKD) and GFR stages in a sample of U.S. adults, using current and new equations. RESULTS In the validation data set, the current creatinine equation that uses age, sex, and race overestimated measured GFR in Blacks (median, 3.7 ml per minute per 1.73 m² of body-surface area; 95% confidence interval [CI], 1.8 to 5.4) and to a lesser degree in non-Blacks (median, 0.5 ml per minute per 1.73 m²; 95% CI, 0.0 to 0.9). When the adjustment for Black race was omitted from the current eGFR equation, measured GFR in Blacks was underestimated (median, 7.1 ml per minute per 1.73 m²; 95% CI, 5.9 to 8.8). A new equation using age and sex and omitting race underestimated measured GFR in Blacks (median, 3.6 ml per minute per 1.73 m²; 95% CI, 1.8 to 5.5) and overestimated measured GFR in non-Blacks (median, 3.9 ml per minute per 1.73 m²; 95% CI, 3.4 to 4.4). For all equations, 85% or more of the eGFRs for Blacks and non-Blacks were within 30% of measured GFR. New creatinine-cystatin C equations without race were more accurate than new creatinine equations, with smaller differences between race groups. As compared with the current creatinine equation, the new creatinine equations, but not the new creatinine-cystatin C equations, increased population estimates of CKD prevalence among Blacks and yielded similar or lower prevalence among non-Blacks. CONCLUSIONS New eGFR equations that incorporate creatinine and cystatin C but omit race are more accurate and led to smaller differences between Black participants and non-Black participants than new equations without race with either creatinine or cystatin C alone. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.) [ABSTRACT FROM AUTHOR]

Background: We have developed a nontransformed immortalized mice kidney cortex epithelial cell (MKCC) culture from a mouse transgenic for a recombinant plasmid adeno-SV40 (PK4). Methods and Results. After 12 months in culture, the immortalized cells had a stable homogeneous epithelial-like phenotype, expressed simian virus 40 (SV40) T-antigen, but failed to induce tumors after injection in nude mice. Epithelium exhibited polarity with an apical domain bearing many microvilli separated from lateral domains by junctional complexes with ZO1 protein. The transepithelial resistance was low. A Na-dependent glucose uptake sensitive to phlorizin and a Na-dependent phosphate uptake sensitive to arsenate were present. Western blot analysis of membrane fractions showed that anti-Na-Pi antiserum reacted with a 87 kD protein. The Na/H antiporters NHE-1, NHE-2, and NHE-3 mRNAs were detected by reverse transcription-polymerase chain reaction (RT-PCR). The corresponding proteins with molecular weights of 111, 81, and 75 kD, respectively, could be detected by Western blot and were shown to be functional. Parathyroid hormone (PTH) induced a tenfold increase in cAMP and reduced the Na-dependent phosphate uptake and NHE-3 activity, as observed in proximal tubule cells. Isoforms alpha, delta, epsilon, and zeta of protein kinase C (PKC) were present in the cells. Angiotensin II (Ang II) elicited a translocation of the PKC-alpha toward the basolateral and apical domains.Conclusion: Thus, the MKCC culture retains the structural and functional properties of proximal tubular cells. To our knowledge, it is the first cell culture obtained from transgenic mice that exhibits the NHE-3 antiporter and type II Na-Pi cotransporter. MKCCs also display functional receptors for PTH and Ang II. Thus, MKCCs offer a powerful in vitro system to study the cellular mechanisms of ion transport regulation in proximal epithelium. [ABSTRACT FROM AUTHOR]