Postanesthesia ultrasound facilitates creation of more preferred accesses without affecting access survival.

OBJECTIVE: The results of preoperative ultrasound (pre-US) vein mapping for hemodialysis access creation can be affected by environmental and clinical factors, such as ambient temperature, acute illness, recent phlebotomy, and hypovolemia. These factors may inadvertently exclude otherwise viable veins as options for access creation. We hypothesized that repeating the ultrasound vein mapping immediately preoperatively after anesthesia administration (post-US) identifies additional veins not appreciated by pre-US, thereby altering the operative plan and producing more preferred accesses, particularly more forearm accesses. METHODS: We performed a retrospective cohort study of patients (N = 323) at one institution who underwent pre-US followed by creation of a permanent dialysis access (fistula or graft) between January 2008 and December 2013. By applying the Silva criteria to pre-US vein mapping reports, a preoperative surgical plan was established. There were 99 patients who underwent only pre-US (group I); an additional post-US was performed in 224 patients (group II). Using multivariable logistic regression, we tested the association of post-US (group II) with pre-US alone (group I) with a change in operative plan and placement of a more preferred access (ie, more distal and autogenous). We also analyzed access survival using multivariable Cox proportional hazards regression and determined maturation rates for accesses in groups I and II. RESULTS: In group II, there were more changes in operative plan after controlling for potential confounders (adjusted odds ratio, 1.96; 95% confidence interval, 1.18-3.25), and more preferred accesses were created (adjusted odds ratio, 1.82; 95% confidence interval, 1.01-3.27). In addition, more autogenous accesses were created in group II when initially only upper arm graft options had been identified (P = .01); overall, more forearm accesses were created in group II (P = .03). There was no significant difference in access maturation and patency in comparing accesses in group I and group II, despite creation of autogenous accesses in group II that are usually associated with higher rates of access failure. In fact, forearm radial-cephalic autogenous accesses created in group II had secondary patency rates of 91% at 2 years. CONCLUSIONS: Our study supports the hypothesis that the use of post-US in addition to pre-US leads to placement of more preferred accesses while maintaining maturation and patency rates. Ultrasound evaluation after anesthesia should be considered a step in the process of care for hemodialysis access creation to improve outcomes.

Improved outcomes with proximal radial-cephalic arteriovenous fistulas compared with brachial-cephalic arteriovenous fistulas.

BACKGROUND: Brachial-cephalic arteriovenous fistulas (BCFs) are associated with high-flow volumes, leading to potential risks such as arm swelling, steal syndrome, pseudoaneurysm (due to a pressurized access), and cephalic arch stenosis. We hypothesized that a proximal radial-cephalic fistula (prRCF) configuration mitigates these risks because a lower flow state is created. Furthermore, we also hypothesized that despite these lower flows, patencies (primary, primary assisted, secondary) are sustained. METHODS: Leveraging a prospectively collected database supplemented with detailed medical record data, analyses of patients undergoing BCF and prRCF were completed (November 2008 through March 2016). Preoperative clinical and imaging characteristics, operative variables, and postoperative complications were reviewed. The primary end point was a composite of arm swelling, steal, and pseudoaneurysm at 2 years. Fistulograms and interventions (surgical revision, thrombectomy, endovascular treatment of cephalic arch stenosis) censored at 2 years were compared between configurations. Patencies were plotted using Kaplan-Meier techniques and compared using Cox proportional hazards. RESULTS: During the study period, 345 arteriovenous fistulas and 72 prosthetic grafts were primarily placed; 56 patients underwent BCF and 50 patients underwent prRCF with a mean follow-up of 1.8 ± 1.7 (standard deviation) years. Except for prRCF patients being older, there was no difference between the groups with regard to preoperative characteristics. The artery diameter used for anastomosis was significantly larger in the BCF group (4.0 ± 1.1 mm vs 2.6 ± 0.8 mm; P < .001), with higher flow volumes at 6-week ultrasound examination (1060 ± 587 mL/min vs 735 ± 344 mL/min; P < .001). Complications (arm swelling, steal, pseudoaneurysm) were significantly more common in the BCF group (P = .02). There was a trend, albeit statistically insignificant, for the BCF group to require more cephalic arch stenosis interventions. Of those patients needing dialysis within 1 year, both BCF and prRCF were successfully used in the majority of patients (n = 27 [66%] vs n = 25 [63%]; P = 1.0). Unadjusted and adjusted primary, primary assisted, and secondary patency rates were similar between the groups. CONCLUSIONS: prRCFs have fewer complications yet similar midterm durability compared with BCFs. When it is anatomically feasible, prRCFs should be constructed over BCFs because of their superior physiology and clinical outcomes.

A quantitative, facile, and high-throughput image-based cell migration method is a robust alternative to the scratch assay.

Cell migration is a key phenotype for a number of therapeutically important biological responses, including angiogenesis. A commonly used method to assess cell migration is the scratch assay, which measures the movement of cells into a wound made by physically scoring a confluent cell monolayer to create an area devoid of cells. Although this method has been adequate for qualitative characterization of migration inhibitors, it does not provide the highly reproducible results required for quantitative compound structure-activity relationship evaluation because of the inconsistent size and placement of the wound area within the microplate well. The Oris™ Cell Migration Assay presents a superior alternative to the scratch assay, permitting formation of precisely placed and homogeneously sized cell-free areas into which migration can occur without releasing factors from wounded or dead cells or damaging the underlying extracellular matrix. Herein the authors compare results from the scratch and Oris™ cell migration assays using an endothelial progenitor cell line and the Src kinase inhibitor dasatinib. They find that using the Acumen™ Explorer laser microplate cytometer in combination with the Oris™ Cell Migration Assay plate provides a robust, efficient, and cost-effective cell migration assay exhibiting excellent signal to noise, plate uniformity, and statistical validation metrics.

Conduct unbecoming: C-reactive protein interactions with a broad range of protein molecules.

BACKGROUND: C-reactive protein (CRP), a pentamer composed of five identical 23-kd subunits, is a member of a highly conserved family of proteins known as pentraxins. CRP has been recognized as a risk factor for the development of both the native and transplant-associated forms of atherosclerosis. Understanding the biology of CRP may be relevant to understanding atherosclerosis development and progression. METHODS: Using Western-blotting techniques, we examined the interactions between native, monomeric and mutationally and chemically modified CRP and a variety of antibodies, monoclonal and polyclonal. RESULTS: CRP in its denatured monomeric form, but not in its native pentameric conformation, associates promiscuously with IgG molecules, including normal human IgG, as well as with a number of other proteins. This behavior is intrinsic to CRP and is not noted with other pentraxins such as serum amyloid P component or the long pentraxin, PTX3. Monomeric CRP co-localizes with vitronectin in human heart tissue sections. CONCLUSIONS: We present these findings as cautionary advice, to indicate that characterization of monomeric CRP can be complicated by the propensity of the molecule to interact with a variety of immunoglobulins and other proteins. We also suggest that it is possible that such interactions could serve to eliminate excess of monomeric CRP and/or to scavenge altered, damaged and denatured proteins. These reactivities may be part of a regulatory mechanism to limit inflammation in the arterial wall.

SU1498, an inhibitor of vascular endothelial growth factor receptor 2, causes accumulation of phosphorylated ERK kinases and inhibits their activity in vivo and in vitro.

SU1498, an inhibitor of vascular endothelial growth factor receptor 2, has been used successfully to study the physiological manifestations of receptor functions. Here we report that in addition to its anti-receptor activity, SU1498 stimulates accumulation of phosphorylated ERKs in human umbilical vein endothelial cells and in human aortic endothelial cells in a manner that is dependent on the functioning of the upstream components of the MAPK pathway, B-Raf, and MEK kinases. The enhanced accumulation of phospho-ERKs is observed only in cells that have been stimulated with sphingosine 1-phosphate or protein growth factors; SU1498 by itself is ineffective. We show that the inhibitor acts by blocking the kinase activity of phospho-ERK both in a direct assay and in immunoprecipitates from cells treated with the compound. The data reveal a novel and unique way in which MAPK signaling pathway may be blocked in human endothelial cells.

Migration of vascular smooth muscle cells induced by sphingosine 1-phosphate and related lipids: potential role in the angiogenic response.

The bioactive lipids sphingosine 1-phosphate (SPP), sphingosylphosphorylcholine, and lysophosphatidic acid play an important role in angiogenesis as a result of their effects on both the migration of endothelial cells (ECs) and the integrity of EC monolayers. Here we show that extremely low concentrations of serum and nanomolar concentrations of these biologically active lipids stimulate migration of human aortic smooth muscle cells (SMCs). However, at dosages most effective in promoting EC migration and in enhancing EC monolayer integrity, serum and SPP potently inhibited SMC migration; SPP also blocked the migration induced by protein growth factors. Treatment of SMCs with SPP induced transient phosphorylation of a 175- to 185-kDa protein corresponding to the PDGF receptor, indicating transactivation of this receptor. SPP and related lipids may play a key role in angiogenesis by coordinating the migration of both endothelial cells and vascular smooth muscle cells in response to the changing gradients of these bioactive lipid messengers.