Publications by authors named "Kuykendall R"

Article Synopsis
  • The study explores the design of stents and conduits with a gradually expanding caliber to reduce flow resistance and prevent flow separation, compared to conventional cylindrical stents.* -
  • Experiments involved testing conduits of various initial calibers (2-5 mm) and lengths (160-620 mm) at different pressures (10 and 25 mm Hg) to evaluate their flow rates in comparison to traditional designs.* -
  • Results showed that the expanding caliber conduits significantly improved flow rates by 1-55%, with computational fluid dynamics simulations confirming optimal expansion rates that minimize flow separation and resistance.*
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Objective: Randomized trials have demonstrated the benefit of thrombus removal strategies in iliofemoral deep venous thrombosis (IFDVT) in providing early symptom relief and decreasing the incidence of post-thrombotic syndrome (PTS), especially severe PTS. However, the impact of quantum of residual thrombus burden (RTB) on PTS as determined by intravascular ultrasound examination and the role of venous stenting in the acute setting have not been evaluated and represent the focus of this study.

Methods: Sixty-nine limbs (65 patients) undergoing thrombus removal for acute symptomatic IFDVT between 2015 and 2021 formed the study cohort.

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Article Synopsis
  • * While generally effective, this technique can lead to a long-term complication where one stent compresses the other due to a compliance mismatch, often going unnoticed without an ultrasound examination.
  • * A possible solution to alleviate this complication could involve creating a cross-fenestration between the stent barrels, reinforced by a Z stent, especially if the barrels have a short extension into the vena cava.
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Minimum iliac vein caliber necessary to maintain normal peripheral venous pressure can be derived by the Poiseuille equation. Duplex was compared to intravascular ultrasound (IVUS) in the assessment of iliac vein stenosis in this single center retrospective study. Parallel IVUS and duplex caliber data for common iliac vein (CIV) and external iliac vein (EIV) in 382 limbs were separately compared.

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Background: Veins are thin-walled tubes. Their lumen is roughly circular with an aspect ratio close to 1:1 under physiologic pressures. When they collapse owing to decreased internal pressure or external compression, the aspect ratio changes.

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Background: Phasic venous flow variation with respiration is surrounded by controversy and not well understood. The current concept assigns a major role to the "abdominal pump." According to this model, inspiratory increases in abdominal pressure compress the vena cava, increasing its internal venous pressure and propelling blood upstream.

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Objective: An endovascular approach has essentially replaced open surgery in the management of symptomatic chronic obstructive iliofemoral venous disease. In the last several years, such a minimally invasive approach has shifted from use of Wallstents alone to a combination of Wallstent-Z stent (composite stenting) to better deal with the iliocaval confluence. This study evaluates the clinical and stent related outcomes following use of composite stenting.

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Background: Iliac vein stenosis is a frequent pathologic process in advanced chronic venous disease. Intravascular ultrasound (IVUS) has emerged as the "gold standard" to diagnose iliac vein stenosis and to guide stent treatment. A pre-IVUS test is often obtained.

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The emergence of azole-resistant has become a clinical problem in many parts of the world. Several amino acid mutations in the azole target protein Cyp51Ap contribute to this resistance, with the most concerning being the environmentally derived TR/L98H and TR/Y121F/T289A mutations. Here, we performed passive surveillance to assess a sample of the population in the United States for the presence of these mutations.

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Antifungal susceptibility testing for Candida species is now widely accepted as a methodology to predict the success or failure of antifungal therapy for some antifungal/Candida species combinations. There are many different ways to perform susceptibility testing of antifungal agents, but broth microdilution has become the most popular over the last 10 years. This chapter describes in detail two methods for antifungal susceptibility testing of Candida species using the commercially available microbroth dilution tray (YeastOne(®)) and a commercially available gradient agar diffusion technique (Etest(®)) for isolates that appear resistant.

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MIC values were generated for caspofungin, micafungin, and anidulafungin against 106 isolates of C. lusitaniae, and these values were compared to established epidemiologic cutoff values. The majority of isolates were wild type both by MIC value as well as by FKS1 hotspot sequencing.

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Echinocandins are the recommended treatment for invasive candidiasis due to Candida glabrata. Resistance to echinocandins is known to be caused by nonsynonymous mutations in the hot spot-1 (HS1) regions of the FKS1 and FKS2 genes, which encode a subunit of the β-1,3-glucan synthase, the target of echinocandins. Here, we describe the development of a microsphere-based assay using Luminex MagPix technology to identify mutations in the FKS1 HS1 and FKS2 HS1 domains, which confer in vitro echinocandin resistance in C.

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Flucytosine and itraconazole are the only antifungal agents for which the Clinical Laboratory and Standards Institute recommendations include MIC breakpoint readings at 48 h only. Here we show good essential and categorical agreement between the flucytosine MIC readings at 48 and 24 h for Candida species.

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Candida albicans, the primary causative agent of candidiasis, is a ubiquitous member of the human flora and is capable of causing severe invasive disease. Despite its importance as a human pathogen, little is known concerning those factors creating and maintaining genetic diversity within the species and how extant strains reflect their evolutionary history. Based on nucleotide polymorphism frequencies, we estimated the time to a most recent common ancestor for the species to be about 3-16 million years, with variation due to molecular clock calibration.

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Isolates of Candida parapsilosis, including representatives of the three major sub-species groups, were screened for single nucleotide polymorphisms (SNPs) by sequencing five independent loci totaling 4kb per isolate. Group I isolates were highly conserved and in some cases, group I alleles were found in group II and III strains. Unique alleles were also associated with groups II and III, consistent with earlier observations of intergroup divergence.

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Candida albicans strain diversity and fluconazole resistance were prospectively analyzed in oral strains from 29 adult human immunodeficiency virus (HIV)-positive patients followed for > 1 year who had five or more culture-positive clinic visits. Molecular typing consisted of genomic blots probed with the Ca3 repetitive element. Sixteen patients had one or more episodes of oropharyngeal candidiasis (OPC), 12 (75%) maintained the original genotype, whereas the remaining four patients had a succession of 2-3 genotypes.

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Background: Candida parapsilosis is a common cause of sporadic and epidemic infections in neonatal intensive care units (NICUs). When a cluster of C. parapsilosis bloodstream infections occurred in NICU patients in a hospital in Louisiana, it provided us with the opportunity to conduct an epidemiologic investigation and to apply newly developed molecular typing techniques.

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A case of chronic vertebrobasilar insufficiency due to severe stenoses at the origins of both vertebral arteries was treated with percutaneous transluminal angioplasty and coronary Palmaz-Schatz stents. Use of stents led to a better angiographic result than angioplasty alone. The patient is improved 8 mo later.

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We evaluated multilocus enzyme electrophoresis (MEE) and random amplified polymorphic DNA (RAPD) for their usefulness in subtyping 344 Cryptococcus neoformans clinical isolates obtained from four U.S. metropolitan areas in 1992 to 1994.

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We have determined the nucleotide sequence for the DNA encoding the 5.8S RNAs and downstream internal transcribed spacer (ITS2) regions for Candida albicans and the taxonomically related species C. parapsilosis, C.

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Aspartyl proteinase (AP) is an extracellular enzyme of Candida albicans implicated as a pathogenic factor. Previous reports on the purification and characterization of AP suggested that a single DEAE-Sephadex chromatographic step was sufficient for the removal of extraneous proteins and that the final product was glycosylated. We purified AP using a chromatographic series consisting of DEAE-Sephadex A25, Sephadex G75 and rechromatography on DEAE-Sephadex A25.

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Three dominant proteins (41, 48, and 49 kDa) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in purified preparations of the extracellular aspartyl proteinase (AP) of Candida albicans. All three proteins bound to the specific carboxyl proteinase ligand, pepstatin A, and were associated with maximum AP activity. The N-terminal amino acid sequence for the 48- and 49-kDa proteins matched that reported by others for AP, whereas the sequence for the 41-kDa protein was unique and was not homologous to any known protein.

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Candida parapsilosis shows a wide intraspecies variation in chromosome/homolog size distribution. As a prerequisite for delineating modes of transmission, we have undertaken an analysis of genetic variation at different levels. In the present study we have observed that a majority of isolates display similar electrophoretic karyotype patterns consistent for the species, with variations in the smaller group of chromosomes.

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