Pathogenesis of hyperadrenergic orthostatic hypotension: Evidence of disordered venous innervation exclusively in the lower limbs

The pathogenesis of hyperadrenergic orthostatic hypotension was studied in eight patients. Correction of the abnormal orthostatic changes by an inflated pressure suit (MAST) confirmed previous evidence of excessive gravitational pooling of blood in the leg veins. Intravenous L-norepinephrine infusion raised diastolic blood pressure in the same relationship to the infusion-induced increments in plasma norepinephrine concentrations as in normal subjects, indicating normal arteriolar responses. Contractile responses of the veins to infused L-norepinephrine were measured with a linear variable differential transformer (LVDT). The venous responses of hand veins in the patients fell within the 95% confidence limits of the responses of normal hand veins, as did the responses of foot veins in the seven normal subjects. However, foot veins of the patients with hyperadrenergic orthostatic hypotension, and both hand and foot veins of patients with "diffuse" autonomic failure, were supersensitive to norepinephrine, as reflected by a steeper slope of the regression of log (norepinephrine infusion rate) on percentage reduction in venous distensibility, and a significantly lower ED50 (i.e., norepinephrine infusion rate that induced 50% reduction in venous distensibility). The findings suggest anatomical or functional postganglionic denervation of lower limb veins causing excessive gravitational blood pooling with consequent orthostatic hypotension in these patients

Stability of Ampelometric Characteristics of Vitis vinifera L. cv. 'Syrah' and 'Sauvignon blanc' Leaves: Impact of Within-vineyard Variability and Pruning Method/Bud Load

Historically, grapevine (Vitis vinifera L.) leaf characterisation has been a driving force in the identification of cultivars. In this study, ampelometric (foliometric) analysis was done on leaf samples collected from hand-pruned, mechanically pruned and minimally pruned ‘Sauvignon blanc’ and ‘Syrah’ vines to estimate the impact of within-vineyard variability and a change in bud load on the stability of leaf properties. The results showed that within-vineyard variability of ampelometric characteristics was high within a cultivar, irrespective of bud load. In terms of the O.I.V. coding system, zero to four class differences were observed between minimum and maximum values of each characteristic. The value of variability of each characteristic was different between the three levels of bud load and the two cultivars. With respect to bud load, the number of shoots per vine had a significant effect on the characteristics of the leaf laminae. Single leaf area and lengths of veins changed significantly for both cultivars, irrespective of treatment, while angle between veins proved to be a stable characteristic. A large number of biometric data can be recorded on a single leaf; the data measured on several leaves, however, are not necessarily unique for a specific cultivar. The leaf characteristics analysed in this study can be divided into two groups according to the response to a change in bud load, i.e. stable (angles between the veins, depths of sinuses) and variable (length of the veins, length of the petiole, single leaf area). The variable characteristics are not recommended to be used in cultivar identification, unless the pruning method/bud load is known

Submarginal Venation of Foliage Leaves

An earlier paper gave a brief account of experiments dealing with the conductive efficiency of certain types of vein systems in foliage leaves. By cutting the blade in various ways it was possible to show some of the advantages and also the disadvantages of different types of venation. The results indicated that larger veins, while highly efficient for conduction along their length, may constitute real barriers to movement across them, especially when interrupted by breaks in the veins, which cuts doubtless lead to leakage. On the other hand, regions free from larger veins showed marked capacity for conduction in all directions. The relatively small veins constituting the islet-borders were found to be capable not only of ready conduction in any direction in the blade but were demonstrably capable of carrying a very great overload

A Hand-Based Biometric Verification System Using Ant Colony Optimization

This paper presents a novel personal authentication system using hand-based biometrics, which utilizes internal (beneath the skin) structure of veins on the dorsal part of the hand and the outer shape of the hand. The hand-vein and the hand-shape images can be simultaneously acquired by using infrared thermal and digital camera respectively. A claimed identity is authenticated by integrating these two traits based on the score-level fusion in which four fusion rules are used for the integration. Before their fusion, each modality is evaluated individually in terms of error rates and weights are assigned according to their performance. In order to achieve an adaptive security in the proposed bimodal system, an optimal selection of fusion parameters is required. Hence, Ant Colony Optimization (ACO) is employed in the bimodal system to select the weights and also one out of the four fusion rules optimally for the adaptive fusion of the two modalities to meet the user defined security levels. The databases of hand-veins and the hand-shapes consisting of 150 users are acquired using the peg-free imaging setup. The experimental results show genuine acceptance rate (GAR) of 98% at false acceptance rate (FAR) of 0.001% and the system has the potential for any online personal authentication based application.

Abnormal communication between cephalic and basilic veins-a case report

The cephalic vein and basilic vein begin respectively from lateral and medial ends of the dorsal venous arch of hand. The basilic vein is confined to the medial side of upper limb and continues upwards as the axillary vein whereas the cephalic vein is confined to the lateral side of upper limb and drains into the axillary vein. The aforesaid veins communicate with one another through the median cubital vein that lies in the roof of cubital fossa. The superficial veins are used for venepuncture, cardiac catheterization, bypass grafting and arteriovenous fistula for hemodynamic access. The authors chanced upon a variation in the cephalic and basilic veins in the right upper limb of a cadaver of a sixty years old female dying due to natural causes. The cadaver was used for routine dissection classes of first year MBBS students in a medical college of Eastern India. The cephalic and basilic veins of the said cadaver joined with each other in the cubital fossa. The brachial vein began from the point of union of the two former superficial veins and the single brachial vein replaced the paired brachial veins which is usually the norm

Leaf venation networks of Bornean trees: images and hand-traced segmentations.

The data set contains images of leaf venation networks obtained from tree species in Malaysian Borneo. The data set contains 726 leaves from 295 species comprising 50 families, sampled from eight forest plots in Sabah. Image extents are approximately 1 × 1 cm, or 50 megapixels. All images contain a region of interest in which all veins have been hand traced. The complete data set includes over 30 billion pixels, of which more than 600 million have been validated by hand tracing. These images are suitable for morphological characterization of these species, as well as for training of machine-learning algorithms that segment biological networks from images. Data are made available under the Open Data Commons Attribution License. You are free to copy, distribute, and use the database; to produce works from the database; and to modify, transform, and build upon the database. You must attribute any public use of the database, or works produced from the database, in the manner specified in the license. For any use or redistribution of the database, or works produced from it, you must make clear to others the license of the database and keep intact any notices on the original database

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

Local effect of transdermal isosorbide dinitrate ointment on hand vein diameter

Abstract.: Objective: To assess the effect of topically applied isosorbide dinitrate (ISDN) ointment on superficial hand veins preconstricted with phenylephrine. Methods: Using the hand vein compliance technique, venous diameter changes were measured in a double-blind, randomised, placebo-controlled cross-over trial in 12 healthy volunteers. During preconstriction with phenylephrine, placebo or ISDN ointment was administered to assess the dilator effect of transdermal ISDN. Finally a single i.v. dose of nitroglycerine was administered into the hand vein to assess the maximal venous response to organic nitrovasodilators. Results: ISDN ointment (equivalent to 13.4±3.61mg ISDN) caused a significant dilator effect of 39.1±21.7% (mean±SEM, P=0.02) which reached its maximum after 42.5±16.6min. Maximum ISDN effects were inversely correlated with venous baseline diameter (r2=0.38, P=0.03) and independent of the amount of ointment applied or the extent of preconstriction (P>0.3). Conclusion: Similar to nitroglycerine, topical ISDN may relax superficial hand veins within 60min after application, suggesting that it might ease venepuncture particularly of small vessels. The large variability of the effect and the time to reach the effect, however, restrict its practical usefulnes