Is fetuin-A a biomarker of dialysis access dysfunction?

Background: The arteriovenous (AV) access function of hemodialysis (HD) patients can be impaired by afferent artery stiffness due to preexisting microcalcification and by venous stenosis secondary to neointimal hyperplasia in whose development participates an upregulated local inflammatory process. Fetuin-A is a circulating potent inhibitor of vascular calcification and plays an important anti-inflammatory role. The aims of this prospective study were to investigate the relationship between baseline serum fetuin-A levels and: blood flow (Q) values at baseline, AV access failure (thrombosis or intervention for stenosis) during follow-up and primary unassisted AV access patency.

The impact of pre-existing radial artery pathology by histological assessment on the maturation, function and patency of the radiocephalic fistula for hemodialysis.

Background: We prospectively analyzed the effect of preexisting structural changes of the radial artery (RA) wall by histological examination on the wrist radiocephalic fistula (RCF) outcomes.

Methods: During RCF creation, one segment of the RA wall was collected and its histomorphometric analysis was performed. The RCF function was evaluated by measuring blood flow rate.

Evaluation of the clinical usefulness of a health-related quality of life questionnaire in patients with prostate cancer.

Objectives: The PROSQoLI questionnaire evaluates health related quality of life in patients with advanced prostate cancer. Although its utility in different clinical settings has never been assessed, its brevity and good measurement properties make its use recommendable in clinical practice. The objective is to evaluate the clinical usefulness of PROSQoLI in clinical treatment decision-making in patients with prostate cancer.

The effect of loop residues in four-stranded dimeric structures stabilized by minor groove tetrads.

Some DNA oligonucleotides can fold back and self-associate forming dimeric structures stabilized by intermolecular base pairs. The resulting antiparallel dimer is a tightly packed four-stranded structure formed by a core of minor groove tetrads connected by short loops of unpaired nucleotides. We have explored the sequential requirements for the loop residues and have found that this family of structures is only stable with one- and two-residue loops, with the stability of the former ones being only marginal.

The glmS ribozyme cofactor is a general acid-base catalyst.

The glmS ribozyme is the first natural self-cleaving ribozyme known to require a cofactor. The d-glucosamine-6-phosphate (GlcN6P) cofactor has been proposed to serve as a general acid, but its role in the catalytic mechanism has not been established conclusively. We surveyed GlcN6P-like molecules for their ability to support self-cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of the cofactors.

A minimal i-motif stabilized by minor groove G:T:G:T tetrads.

The repetitive DNA sequences found at telomeres and centromeres play a crucial role in the structure and function of eukaryotic chromosomes. This role may be related to the tendency observed in many repetitive DNAs to adopt non-canonical structures. Although there is an increasing recognition of the importance of DNA quadruplexes in chromosome biology, the co-existence of different quadruplex-forming elements in the same DNA structure is still a matter of debate.

Study of arteriovenous fistula function by the temperature gradient method using the Twister™ device.

Introduction: Periodic blood flow (QA) measurement is the preferred way for arteriovenous fistula (AVF) surveillance in chronic hemodialysis (HD) patients. Objectives. 1) Assess the efficacy of the temperature gradient method (TGM) on the QA determinations using the Twister™ device and to compare the functional results with the Delta-H method.

Five years of vascular access stenosis surveillance by blood flow rate measurements during hemodialysis using the Delta-H method.

Purpose: To report experience over five years of vascular access (VA) stenosis surveillance.

Methods: We prospectively monitored the blood flow rate (QA) of 145 VA in 131 ESRD (age 62.6 ±13.

An active-site guanine participates in glmS ribozyme catalysis in its protonated state.

Active-site guanines that occupy similar positions have been proposed to serve as general base catalysts in hammerhead, hairpin, and glmS ribozymes, but no specific roles for these guanines have been demonstrated conclusively. Structural studies place G33(N1) of the glmS ribozyme of Bacillus anthracis within hydrogen-bonding distance of the 2'-OH nucleophile. Apparent pK(a) values determined from the pH dependence of cleavage kinetics for wild-type and mutant glmS ribozymes do not support a role for G33, or any other active-site guanine, in general base catalysis.

Structure and stability of a dimeric g-quadruplex formed by cyclic oligonucleotides.

We have studied the structure and stability of the cyclic dodecamer d, containing two copies of the human telomeric repeat. In the presence of sodium, NMR data are consistent with a dimeric structure of the molecule in which two cycles self-associate forming a quadruplex with three guanine tetrads connected by edgewise loops. The two macrocycles are arranged in a parallel way, and the dimeric structure exhibits a high melting temperature.

Self-association of cyclic oligonucleotides through G:T:G:T minor groove tetrads.

Minor groove aligned tetrads resulting from the association of Watson-Crick base pairs stabilize a distinct class of four-stranded DNA structures, different from G-quadruplexes or i-motifs. These tetrads can be formed by several arrangements of G-C or A-T base pairs. Here we prove that minor groove tetrads can be also formed by G-T mismatches.

[Functional profile of cephalic arch stenosis].

Cephalic arch stenosis (CAS) is a unique type of vascular access stenosis. For example, the etiology of CAS is under investigation and the prevalence of CAS can be lower in diabetic patients. Three cases of CAS were identified during our vascular access stenosis surveillance program by blood flow rate measurements using the Delta-H method.

Studies on the hydrolytic stability of 2'-fluoroarabinonucleic acid (2'F-ANA).

The stability of 2'-deoxy-2'-fluoroarabinonucleic acid (2'F-ANA) to hydrolysis under acidic and basic conditions was compared to that of DNA, RNA and 2'F-RNA. In enzyme-free simulated gastric fluid (pH approximately 1.2), 2'F-ANA was found to have dramatically increased stability (virtually no cleavage observed after 2 days) with respect to both DNA (t(1/2) approximately 2 min) and RNA (t(1/2) approximately 3 h (PO) or 3 days (PS)).

[Prevalence and functional effect of arteriovenous fistula calcifications, evaluated by spiral CT in chronic haemodialysis patients].

Introduction: Vascular calcification is a common finding in patients (pts) with end-stage renal disease (ESRD).

Objective: The aim of this cross-sectional study was to investigate the prevalence and functional effect of native arteriovenous fistula AVF (feeding artery and/or arterialized vein) calcifications evaluated by spiral computed tomography (CT) in ESRD pts undergoing chronic hemodialysis (HD).

Patients And Method: Forty-five upper limb AVF (radial 44.

Self-association of short DNA loops through minor groove C:G:G:C tetrads.

In addition to the better known guanine-quadruplex, four-stranded nucleic acid structures can be formed by tetrads resulting from the association of Watson-Crick base pairs. When such association occurs through the minor groove side of the base pairs, the resulting structure presents distinctive features, clearly different from quadruplex structures containing planar G-tetrads. Although we have found this unusual DNA motif in a number of cyclic oligonucleotides, this is the first time that this DNA motif is found in linear oligonucleotides in solution, demonstrating that cyclization is not required to stabilize minor groove tetrads in solution.

[Measurement of vascular access blood flow rate during hemodyalisis in 38 patients using the thermodilution technique. A comparative study with the Delta-H method].

Introduction: Periodic QA measurement is the preferred way for VA surveillance in end-stage renal disease (ESRD) patients (pts).

Objective: The aims of this study were to measure QA by TDT and to compare the functional results with Delta-H method.

Patients And Methods: We measured Q(A) non invasively in 38 VA (mean VA duration: 48.

[Noninvasive assessment of forearm vessels by color Doppler ultrasonography (CDU) before and after radiocephalic fistula (RCF) placement].

Introduction: The CDU is a noninvasive vascular access (VA) monitoring technique that provides both structural and hemodynamic information from vessels.

Objective: The aim of this prospective study was to analyze some parameters of forearm vessels by CDU before and after RCF creation at the wrist.

Patients And Methods: We explored by CDU the vessels of forearm in 34 CRF patients (pts) (mean age 63.

[Tesio twin catheter system for hemodialysis tunnelized using an echo-guided technique. Retrospective analysis of 210 catheters].

Purpose: Review a large experience in the placement of tunnelled catheters to assess the outcomes with twin catheter system as hemodialysis access.

Material And Methods: We retrospectively reviewed clinical and hemodialysis data regarding of ESRD patients who were referred from 2 dialysis facilities for placement of tunnelled catheters hemodialysis access between 1996 March and 2005 July. For catheter insertion a real-time sonography technique was used (Site Rite II Dymax corporation) in performing vascular access procedure.

[Prevalence and functional profile of unsuspected radial artery stenosis in native radiocephalic fistula dysfunction. Diagnosis by vascular access flow monitoring using Delta-H method].

Objective: The aim of this study was to know the prevalence and functional profile of RA stenosis in RCF dysfunction detected as a result of our surveillance programme.

Patients And Methods: We prospectively monitored QA of 116 VA (arteriovenous fistula 81% or graft 19%; mean VA duration 28.2 +/- 52.

Induced-fit recognition of DNA by small circular oligonucleotides.

We have investigated the molecular interaction between cyclic and linear oligonucleotides. We have found that short cyclic oligonucleotides can induce hairpinlike structures in linear DNA fragments. By using NMR and CD spectroscopy we have studied the interaction of the cyclic oligonucleotide d with d, as well as with its two linear analogs d(GTCCCTCA) and d(CTCAGTCC).

Functional vascular access evaluation after elective intervention for stenosis.

Purpose: To evaluate the functional effects of preventive vascular access (VA) intervention through periodic blood flow (Q A ) measurements during hemodialysis (HD) by the delta-H method.

Methods: We prospectively monitored the blood flow rate (Q A ) of 100 VA (arteriovenous fistula (AVF) 81% or AV graft (AVG) 19%; mean VA duration 24.6 +/- 42.

[Study of vascular access (VA) by color Doppler ultrasonography (CDU). Comparison between delta-H and CDU methods in measuring VA blood flow rate].

Introduction: The color Doppler ultrasonography (CDU) is a noninvasive vascular access (VA) monitoring technique that provides both structural and hemodynamic information from VA. On the other hand, the delta-H (AH) method is another noninvasive technique that measures the VA blood flow rate during hemodialysis (HD).

Objective: 1) To analyze some anatomic and functional parameters of VA by CDU.

[Non-invasive monitoring of a humeral arteriovenous fistula with hemodynamic repercussions].

A 70-year-old woman, who undergoing hemodialysis due to chronic pyelonephritis, is reported. She suffered from dyspnea due to pulmonary artery hypertension secondary to volume overload as a complication of high-flow brachial AVF. The combined estimation of vascular access blood flow rate (QA) and systolic pulmonary artery pressure by noninvasive methods (ultrafiltration and Doppler echocardiography, respectively) allowed us the diagnosis, make a surgical indication and post-surgical follow-up of AVF with hemodynamic repercussion.

Megautricles: embryogenic hypothesis.

We present 4 cases of megautricle emphasizing the relationship between it and the ejaculatory ducts. We develop an embryogenic hypothesis to explain the different forms of megautricles in relation to the seminal pathway.