Selective two-stage basilic and cephalic vein transpositions can significantly improve the rate of fistula construction

INTRODUCTION:

Modified proximal radial artery arteriovenous fistula (MPRAVF) can be used to improve the success and patency of basilic vein transposition (BVT) and cephalic vein transposition (CVT). In the present study, surgical experience with patients requiring a two-stage BVT or CVT using MPRAVF as the first stage was reviewed.

METHODS:

All two-stage BVTs and CVTs performed between September 2004 and October 2006 were retrospectively reviewed. The median follow-up for this cohort was 23.7 months. One-year secondary patency of all transpositions was assessed.

RESULTS:

Two hundred nineteen MPRAVFs were constructed. Twelve MPRAVFs failed and underwent a second procedure. Ninety-eight patients required no further procedures and their upper arm cephalic vein was matured and used for dialysis. Of 121 patients whose MPRAVFs were functioning but unusable due to their depth, 87 underwent BVT and 34 underwent CVT. The Kaplan-Meier one-year secondary patencies (± standard error) for BVTs and CVTs were 0.90±0.03 and 0.82±0.06, respectively. At one year, 87% of all transpositions remained patent.

CONCLUSIONS:

Use of MPRAVF as the first stage of a two-stage BVT or CVT can significantly improve the patency rate of autogenous hemodialysis access placement beyond the 66% set forth by the Fistula First guidelines.     

Late occurrence of fatal aortitis: a complication of Aspergillus endocarditis following coronary artery bypass graft surgery

The most common fungal organism to cause endocarditis is Candidawhich is followed by Aspergillus. Aspergillus endocarditis canoccur in either the native or prosthetic heart valves, usuallyoccurs post-operative after cardiac valve surgery. This caseis illustrative of a 49-year-old man with previous history ofcoronary artery bypass grafting presenting with aortic valveendocarditis which was diagnosed as Aspergillus endocarditis.Unfortunately, despite medical and surgical therapy, progressivefatal aortic invasion occurred.     

An N-terminal variant of Trpv1 channel is required for osmosensory transduction

Body fluid homeostasis requires the release of arginine-vasopressin (AVP, an antidiuretic hormone) from the neurohypophysis. This release is controlled by specific and highly sensitive 'osmoreceptors' in the hypothalamus. Indeed, AVP-releasing neurons in the supraoptic nucleus (SON) are directly osmosensitive, and this osmosensitivity is mediated by stretch-inhibited cation channels. However, the molecular nature of these channels remains unknown. Here we show that SON neurons express an N-terminal splice variant of the transient receptor potential vanilloid type-1 (Trpv1), also known as the capsaicin receptor, but not full-length Trpv1. Unlike their wild-type counterparts, SON neurons in Trpv1 knockout (Trpv1(-/-)) mice could not generate ruthenium red-sensitive increases in membrane conductance and depolarizing potentials in response to hyperosmotic stimulation. Moreover, Trpv1(-/-) mice showed a pronounced serum hyperosmolality under basal conditions and severely compromised AVP responses to osmotic stimulation in vivo. These results suggest that the Trpv1 gene may encode a central component of the osmoreceptor.     

The ACTCellerate initiative: large-scale combinatorial cloning of novel human embryonic stem cell derivatives

Human embryonic stem cells offer a scalable and renewable source of all somatic cell types. Human embryonic progenitor (hEP) cells are partially differentiated endodermal, mesodermal and ectodermal cell types that have not undergone terminal differentiation and express an embryonic pattern of gene expression. Here, we describe a large-scale and reproducible method of isolating a diverse library of clonally purified hEP cell lines, many of which are capable of extended propagation in vitro. Initial microarray and non-negative matrix factorization gene-expression profiling suggests that the library consists of at least 140 distinct clones and contains many previously uncharacterized cell types derived from all germ layers that display diverse embryo- and site-specific homeobox gene expression. Despite the expression of many oncofetal genes, none of the hEP cell lines tested led to tumor formation when transplanted into immunocompromised mice. All hEP lines studied appear to have a finite replicative lifespan but have longer telomeres than most fetal- or adult-derived cells, thereby facilitating their use in the manufacture of purified lineages for research and human therapy.     

Saccadic and smooth pursuit eye movements: computational modeling of a common inhibitory mechanism in brainstem

The oculomotor system coordinates different types of eye movements in order to orient the visual axis, including saccade and smooth pursuit,. It was traditionally thought that the premotor pathways for these different eye movements are largely separate. In particular, a group of midline cells in the pons called omnipause neurons were considered to be part of only the saccadic system. Recent experimental findings have shown activity modulation of these brainstem premotor neurons during both kinds of eye movements. In this study, we propose a new computational model of the brainstem circuitry underlying the generation of saccades and smooth pursuit eye movements. Similar models have been developed earlier, but mainly looking at pure saccades. Here, we integrated recent neurophysiological findings on omnipause neuron activity during smooth pursuit. Our computational model can mimic some new experimental findings as the similarity of "eye velocity profile" with "omnipause neuron pattern of activity" in pursuit movement. We showed that pursuit neuron activity is augmented during catch-up saccades; this increment depends on the initial pursuit velocity in catch-up saccade onset. We conclude that saccadic and pursuit components of catch-up saccades are added to each other nonlinearly.     

NOD2 exonic variations in Iranian Crohn's disease patients

Purpose

The NOD2 gene is known to have a strong association with Crohn??s disease, but different trends were reported in occurrence of NOD2 variants in distinct ethnicities. The aim of this study was to assess all exonic sequences of the NOD2 gene in Iranian Crohn's disease patients and healthy controls to identify any existing variation and evaluate their association with Crohn's disease.

Methods

A total of 90 non-related Crohn's disease patients and 120 sex- and age-matched healthy controls of Iranian origin were enrolled in this study. The participants were referred to a tertiary center in a 2-year period (2006?C2008). The exonic regions of the NOD2 gene were amplified by polymerase chain reaction and evaluated by direct sequencing.

Results

A total of 21 sequence variations were identified among all exonic regions of the NOD2 gene, of which eight had an allele frequency of more than 5%. Eight new mutations (one in exon 2 and seven in exon 4) were observed. The three main variants (R702W, G908R, and 1007fs) showed allele frequencies of 13.3%, 2.2%, and 1.7%, respectively. Three new variations (P371T, A794P, and Q908H) and R702W mutation were significantly more frequent in Crohn's disease patients compared to controls.

Conclusions

Eight novel mutations were identified in the NOD2 exons, but the pathophysiological importance of these variants remains unclear. Iranian patients with their different genetic reservoirs may demonstrate some novel characteristics for disease susceptibility.