Blood flow-induced Notch activation and endothelial migration enable vascular remodeling in zebrafish embryos.

Arteries and veins are formed independently by different types of endothelial cells (ECs). In vascular remodeling, arteries and veins become connected and some arteries become veins. It is unclear how ECs in transforming vessels change their type and how fates of individual vessels are determined. In embryonic zebrafish trunk, vascular remodeling transforms arterial intersegmental vessels (ISVs) into a functional network of arteries and veins. Here we find that, once an ISV is connected to venous circulation, venous blood flow promotes upstream migration of ECs that results in displacement of arterial ECs by venous ECs, completing the transformation of this ISV into a vein without trans-differentiation of ECs. Arterial blood flow initiated in two neighboring ISVs prevents their transformation into veins by activating Notch signaling in ECs. Together, different responses of ECs to arterial and venous blood flow lead to formation of a balanced network with equal numbers of arteries and veins

Using a novel source-localized phase regressor technique for evaluation of the vascular contribution to semantic category area localization in BOLD fMRI.

Numerous studies have shown that gradient-echo blood oxygen level dependent (BOLD) fMRI is biased toward large draining veins. However, the impact of this large vein bias on the localization and characterization of semantic category areas has not been examined. Here we address this issue by comparing standard magnitude measures of BOLD activity in the Fusiform Face Area (FFA) and Parahippocampal Place Area (PPA) to those obtained using a novel method that suppresses the contribution of large draining veins: source-localized phase regressor (sPR). Unlike previous suppression methods that utilize the phase component of the BOLD signal, sPR yields robust and unbiased suppression of large draining veins even in voxels with no task-related phase changes. This is confirmed in ideal simulated data as well as in FFA/PPA localization data from four subjects. It was found that approximately 38% of right PPA, 14% of left PPA, 16% of right FFA, and 6% of left FFA voxels predominantly reflect signal from large draining veins. Surprisingly, with the contributions from large veins suppressed, semantic category representation in PPA actually tends to be lateralized to the left rather than the right hemisphere. Furthermore, semantic category areas larger in volume and higher in fSNR were found to have more contributions from large veins. These results suggest that previous studies using gradient-echo BOLD fMRI were biased toward semantic category areas that receive relatively greater contributions from large veins

Formation of iddingsite veins in the martian crust by centripetal replacement of olivine: evidence from the nakhlite meteorite Lafayette

The Lafayette meteorite is an olivine clinopyroxenite that crystallized on Mars ∼1300 million years ago within a lava flow or shallow sill. Liquid water entered this igneous rock ∼700 million years later to produce a suite of secondary minerals, collectively called ‘iddingsite’, that occur as veins within grains of augite and olivine. The deuterium/hydrogen ratio of water within these secondary minerals shows that the aqueous solutions were sourced from one or more near-surface reservoirs. Several petrographically distinct types of veins can be recognised by differences in their width, shape, and crystallographic orientation. Augite and olivine both contain veins of a very fine grained hydrous Fe- and Mg-rich silicate that are ∼1-2 micrometres in width and lack any preferred crystallographic orientation. These narrow veins formed by cementation of pore spaces that had been opened by fracturing and probably in response to shock. The subset of olivine-hosted veins whose axes lie parallel to (001) have serrated walls, and formed by widening of the narrow veins by interface coupled dissolution-precipitation. Widening started by replacement of the walls of the narrow precursor veins by Fe-Mg silicate, and a crystallographic control on the trajectory of the dissolution-precipitation front created micrometre-scale {111} serrations. The walls of many of the finely serrated veins were subsequently replaced by siderite, and the solutions responsible for carbonation of olivine also partially recrystallized the Fe-Mg silicate. Smectite was the last mineral to form and grew by replacement of siderite. This mineralization sequence shows that Lafayette was exposed to two discrete pulses of aqueous solutions, the first of which formed the Fe-Mg silicate, and the second mediated replacement of vein walls by siderite and smectite. The similarity in size, shape and crystallographic orientation of iddingsite veins in the Lafayette meteorite and in terrestrial basalts demonstrates a common microstructural control on water-mineral interaction between Mars and Earth, and indicates that prior shock deformation was not a prerequisite for aqueous alteration of the martian crust

Cartilaginous metaplasia of varicose veins: a case report

Cartilaginous metaplasia of superficial veins was found in a 64-year-old woman who underwent surgery for varicose veins. At operation, some varicose veins of the medial thigh were semi-rigid and fibroelastic to the touch. Histology revealed that half the lumen was occupied by chondroid tissue. The other half was obliterated by fibrous tissue, typical of post-thrombotic involution. Possible causes of cartilaginous metaplasia are briefly discussed

Diagnosis of venous incompetence inerectile dysfunction

In 26 of 214 patients with erectile dysfunction and proved venous incompetence by cavernosography, an additional bidirectional Doppler ultrasound was performed also to demonstrate venous outflow disturbances. All except one leakage in the superficial and deep dorsal veins could be demonstrated as well as 4 of 6 cavernosum-glandular shunts. Bidirectional Doppler ultrasound visualized a continuous retrograde blood flow from the sulcus coronarius to the root of the penis in superficial and deep dorsal penile veins as well as in ectopic penile veins, an orthograde blood flow in the sulcus coronarius in cavernosum-glandular shunt

A comparative study between visual, near infrared and infrared images for the detection of veins for intravenous cannulation

The process of identification and locating of veins plays an important role to reduce health care cost and suffering of patients during intravenous cannulation. This paper compares between three technologies to assess their suitability and capability for the detection of veins. Three types of cameras are used in this study, a visual camera, an infrared camera and a near infrared camera. The collected data has then been subjected to analysis and comparison using different image processing techniques, namely grayscale, invert grayscale, histogram equalisation, edge detection (difference of Gaussians) and unsharp mask enhancement to improve the visualisation of veins. In this study, the near infrared images supported by suitable LED illumination has been found to be the most effective technology and the most cost effective for the visualisation of veins

Mechanical Properties of Coronary Veins

There are several publications available and experiments were done regarding to the vessel biomechanical properties. In the range we could find in vitro and in vivo assessments data for elasticity properties. Even though we have many results in this topic we still don’t have enough data for special veins. Three coronary veins were investigated from pig’s heart. The aim of these experiments was to define and measure the longitudinal tensile stress and tensile strength of coronary veins. The tensile tests were done successfully and the tensile stress was defined in the range of 1.66-2.57 MPa

Pre-terrestrial origin of rust in the Nakhla meteorite

The authors present quantative elemental compositions and summarize textural evidence for the pre-terrestrial origin of rust on the Nakhla meteorite. The material in question is called 'rust' because its phase composition remains unknown. Compelling evidence for the pre-terrestrial origin of the rust is found in rust veins truncated by fusion crust and preserved as faults in sutured igneous crystals. Rust veins that approach the meteorite's fusion crust become discontinuous and exhibit vugs that suggest partial decrepitation; no veins that penetrate the fusion crust have been found. Because the rust probably contains volatile compounds, it is reasonable to expect that heating near the ablation surface (formed during atmospheric entry to Earth) would encourage devolatilization of the rust. Hence, the absence of rust veins in fusion crust and vugs in rust veins near fusion crust clearly imply that the rust existed in the meteorite before atmospheric entry

Report on geophysical and geological surveys at Blackmount, Argyllshire

Blackmount, on the southern fringe of Rannoch Moor is largely drift covered but, where exposed, the underlying Precambrian Moine psammite contains granitic veins which probably stem from the adjacent (Devonian) Moor of Rannoch granite. These veins are generally pyritiferous and, at one locality, carry small amounts of molybdenite. Blackmount is also traversed by the Ericht-Laidon Fault, which, in theory, and by analogy with a similar fault to the south-east (the Tyndrum Fault), could be a site of significant sulphide mineralisation. Magnetic, very low frequency electro-magnetic (VLF EM), slingram EM and induced polarisation measurements carried out in the area of the veins suggest that the mineralisation has little or no lateral or depth continuation. Similar surveys were successful in locating the Ericht-Laidon Fault beneath drift, but suggest no associated mineralisation down to the\ud greatest depth investigated

Influence of Long-term Cytotoxic Chemotherapy on the Condition of Peripheral Venous Channel

The necessity of long-term venous access in cancer patients appears at frequent and long-term courses of cytotoxic therapy. Peripheral veins of forearms are most often used for these aims. The conditions of peripheral venous channel in 32 cancer patients, who underwent the long-term treatment with antitumor preparations were analyzed in the article on own investigatory material.The methods of dopplerography, morphological and immunohystochemical studies were used. The qualitative and quantitative dopplerographic changes in forearm veins in different terms after chemotherapy start were revealed in most patients. The conclusion was made about unsuitability of forearm peripheral veins for the long term administration of cytostatics and the necessity to create the alternative vascular access that would correspond to the criteria of safety, reliability and long-term exploitation