The Kinetics of Cystatin C: A Marker for Dialysis Adequacy

When 90% or more of native kidney function is lost, renal replacement therapy must be initiated to sustain life. Renal transplantation is the preferred method, but availability is limited. The ideal dialysis prescription remains elusive. Small molecular weight molecules (such as urea and creatinine) have been used as markers of both kidney (native and transplant) and dialysis toxin clearance (function), but there are pitfalls in using these markers to assess total ‘renal’ dose (kidney plus dialysis). Body weight, gender and other factors also affect the concentrations of these small molecules, but not cystatin C. Furthermore, cystatin C has been shown to be a better marker for estimating kidney function than creatinine, and is associated with cardiovascular morbidity and mortality. Studies have shown that it is removed by dialysis. Therefore, we investigated the use of cystatin C, a naturally occurring endogenous protein, as a marker for estimating dialysis adequacy and renal clearance. This investigation was comprised of four studies to understand the kinetics of cystatin C in patients with advanced kidney disease with or without dialysis. We found that the amount of cystatin C reduction was influenced positively by hemodialysis blood flow rate and treatment time, and negatively by ultrafiltration rate. We further demonstrated that renal hyperfiltration significantly influenced the error of creatinine-based glomerular filtrate rate equation, but not for the cystatin C equation. Therefore, cystatin C appears to be a useful marker for the assessment of kidney function in patients with advanced kidney disease but not yet on dialysis. This was taken further in our third study where we developed an equation, which gave a better estimate of residual renal function than previously published equations in patients on dialysis but who have some remaining kidney function. Finally, we confirmed our hypothesis that cystatin C is cleared during dialysis by both diffusion and convection. It is distributed mainly in the extracellular space but equilibrates slowly between the extravascular and intravascular spaces. Furthermore, we have shown that cystatin C while cleared by dialysis is stable between dialysis treatments rather than being influenced by a single dialysis treatment. It is a marker for both dialysis and renal clearances and, thus, gives a stable index of total renal clearance. The long term goal will be to define the cystatin C threshold level that influences patient morbidity and mortality and to allow better dialysis prescriptions for patients with varying (and changing) residual renal function

Task-Adaptive Negative Class Envision for Few-Shot Open-Set Recognition

Recent works seek to endow recognition systems with the ability to handle the open world. Few shot learning aims for fast learning of new classes from limited examples, while open-set recognition considers unknown negative class from the open world. In this paper, we study the problem of few-shot open-set recognition (FSOR), which learns a recognition system robust to queries from new sources with few examples and from unknown open sources. To achieve that, we mimic human capability of envisioning new concepts from prior knowledge, and propose a novel task-adaptive negative class envision method (TANE) to model the open world. Essentially we use an external memory to estimate a negative class representation. Moreover, we introduce a novel conjugate episode training strategy that strengthens the learning process. Extensive experiments on four public benchmarks show that our approach significantly improves the state-of-the-art performance on few-shot open-set recognition. Besides, we extend our method to generalized few-shot open-set recognition (GFSOR), where we also achieve performance gains on MiniImageNet

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

Few-Shot Object Detection with Fully Cross-Transformer

Few-shot object detection (FSOD), with the aim to detect novel objects using very few training examples, has recently attracted great research interest in the community. Metric-learning based methods have been demonstrated to be effective for this task using a two-branch based siamese network, and calculate the similarity between image regions and few-shot examples for detection. However, in previous works, the interaction between the two branches is only restricted in the detection head, while leaving the remaining hundreds of layers for separate feature extraction. Inspired by the recent work on vision transformers and vision-language transformers, we propose a novel Fully Cross-Transformer based model (FCT) for FSOD by incorporating cross-transformer into both the feature backbone and detection head. The asymmetric-batched cross-attention is proposed to aggregate the key information from the two branches with different batch sizes. Our model can improve the few-shot similarity learning between the two branches by introducing the multi-level interactions. Comprehensive experiments on both PASCAL VOC and MSCOCO FSOD benchmarks demonstrate the effectiveness of our model.Comment: Accepted by CVPR 202

Estimation of GFR using β-trace protein in children

Background and objectives Sexmay affect the performance of smallmolecularweight proteins as markers of GFR because of differences in fat mass between the two sexes. The hypothesis was that the diagnostic performance of b-trace protein, a novel marker of GFR, would be significantly better in boys than in girls. Design, setting, participants, & measurements GFR, height, weight, serum creatinine, and β-trace protein were measured in 755 children and adolescents (331 girls) undergoing 99technetium diethylenetriamine penta–acetic acid renal scans from July of 1999 to July of 2006. Boys and girls were separated into formula generation cohorts (284 boys and 220 girls) and formula validation cohorts (140 boys and 111 girls). GFRestimating formulas on the basis of β-trace protein, creatinine, and height were derived using stepwise linear regression analysis of log-transformed data. The slope of the regression lines of the sex-specific eGFRswere compared. Bland–Altman analysis was used for testing agreement between 99technetium diethylenetriamine penta–acetic acid GFR and calculated GFR both with this equation in boys and girls as well as previously established Benlamri, White, and Schwartz formulas. Results In the stepwise regression analysis, β-trace protein (R2=0.73 for boys and R2=0.65 for girls) was more important than creatinine (which increased R2 to 0.81 for boys and R2 to 0.75 for girls) and height (which increased R2 to 0.88 for boys and R2 to 0.80 for girls) in the data generation groups. GFR can be calculated using the following formulas: formula present Bland–Altman analysis showed better performance in boys than in girls. The new formulas performed significantly better than the previous Benlamri, White, and Schwartz formulas with respect to bias, precision, and accuracy. Conclusions Improved and sex-specific formulas for the estimation of GFR in children on the basis of β-trace protein, serum creatinine, and height are now available

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