Adjoining Vessels Research Articles

Shear Stress and VE-Cadherin.

Objective- Vascular fusion represents an important mechanism of vessel enlargement during development; however, its significance in postnatal vessel enlargement is still unknown. During fusion, 2 adjoining vessels merge to share 1 larger lumen. The aim of this research was to identify the molecular mechanism responsible for vascular fusion. Approach and Results- We previously showed that both low shear stress and DAPT ( N-[ N-(3,5-difluorophenacetyl)-L-alanyl]- S-phenylglycine t-butyl ester) treatment in the embryo result in a hyperfused vascular plexus and that increasing shear stress levels could prevent DAPT-induced fusion. We, therefore, investigated vascular endothelial-cadherin (VEC) phosphorylation because this is a common downstream target of low shear stress and DAPT treatment. VEC phosphorylation increases after DAPT treatment and decreased shear stress. The increased phosphorylation occurred independent of the cleavage of the Notch intracellular domain. Increasing shear stress rescues hyperfusion by DAPT treatment by causing the association of the phosphatase vascular endothelial-protein tyrosine phosphatase with VEC, counteracting VEC phosphorylation. Finally, Src (proto-oncogene tyrosine-protein kinase Src) inhibition prevents VEC phosphorylation in endothelial cells and can rescue hyperfusion induced by low shear stress and DAPT treatment. Moesin, a VEC target that was previously reported to mediate endothelial cell rearrangement during lumenization, relocalizes to cell membranes in vascular beds undergoing hyperfusion. Conclusions- This study provides the first evidence that VEC phosphorylation, induced by DAPT treatment and low shear stress, is involved in the process of fusion during vascular remodeling.

Possible Vascular Injury Due to Screw Eccentricity in Minimally Invasive Total Hip Arthroplasty

Background:Vascular injury during minimally invasive total hip arthroplasty (THA) is uncommon, yet a well-recognized and serious issue. It emerges because of non-visibility of vascular structures proximal to the pelvic bone during reaming, drilling holes, and fixing of screws. Numerous studies have found that screw fixation during cementless THA is beneficial for the initial stability of cup; yet, no anatomical guidelines support angular eccentric screw fixation.Materials and Methods:In this study, we obtained the pelvic arterial-phase computed tomographic data of thirty eight humans and reconstructed the three-dimensional models of osseous and vessel structures. We performed the surgical simulation to fix these structures with cementless cups and screws with angular eccentricities.Results:The effect of screw eccentricities (angular eccentricities of ±17° and ±34°) on the vascular injury was determined. Measurement between screw and adjoining vessels was performed and analyzed statistically to ascertain a comparative risk study for blood vessels that are not visible during surgery.Conclusion:Authors similarly discussed the significant absence of appreciation of quadrant systems proposed by Wasielewski et al. on eccentric screws. Adjustment of quadrant systems provided by Wasielewski et al. is required for acetabular implants with eccentric holes for fixation of acetabular screws.

A Fast and Efficient Region based Aneurysm Segmentation Model for Medical Image Segmentation

Aneurysm and blood vessel delineation from medical images facilitates efficient diagnosis of the Aneurysm and vessels (Stroke or Hemorrhage and Stenosis or malformations) and registration of patient images obtained at different times. Computer-aided diagnosis and detection of Aneurysms via Segmentation algorithms is a complex and multi-faceted issue in medical image processing, as adjoining vessels are the high-intensity structures whereas aneurysms are of low contrast and intensity. Obviously, segmentation is essential to identify the disease severity by change monitoring and also to know further Haemo-dynamic situation in critical cases. Change detection and further analysis gives the complete picture of the case of interest. For Brain tumor detection and analysis, there are several segmentation algorithms but only few are suitable for aneurysm detection and analysis. There is a necessity to provide an efficient segmentation model for aneurysm analysis, change detection and delineation which overcomes the limitations on speed and accuracy of other models. The objective of this paper is to first, apply local binary fitting (LBF), chan-vese (CV) models to aneurysm analysis. Then perform Region based Aneurysm Segmentation model frame work on data sheets of MR Angiography of brain. It is a perfect level set based Active contour model which converges in short span without requirement of any stability and termination criterions. The key feature of this model is that delineation is independent of choice of mask dimensions. Promising results are obtained with the proposed model

Contrast Intravasation During Hysterosalpingography.

SummaryHysterosalpingography is an imaging method to evaluate the endometrial and uterine morphology and fallopian tube patency. Contrast intravasation implies backflow of injected contrast into the adjoining vessels mostly the veins and may be related to factors altering endometrial vascularity and permeability. Radiologists and gynaecologists should be well acquainted with the technique of hysterosalpingography, its interpretation, and intravasation of contrast agents for safer procedure and to minimize the associated complications.

Long-term follow-up is not indicated after routine interventional closure of persistent arterial ducts.

Little is known about the necessity for long-term follow-up after interventional closure of persistent arterial duct (PDA). Potential side effects and complications include residual shunts, haemolysis, device embolization, and obstruction to flow in the adjoining vessels. Single centre retrospective study of paediatric patients undergoing interventional PDA occlusion. 315 patients who underwent interventional occlusion of a PDA between November 2002 and September 2013 were included. Of these, eight needed re-intervention (three for device embolization, five for residual shunt). Seven had mild obstruction to flow in the adjoining vessels, but did not require any intervention. All sequelae were found latest at the first follow-up appointment after the procedure (usually within 3 months); whilst none developed during further follow-up. Complications of interventional closure of PDA were apparent immediately after the procedure or by three months of follow-up. Long-term follow-up is not indicated in cases when no complications are seen early after the procedure.

Bronchoarterial Ratio on High-Resolution CT Scan of the Chest in Children Without Pulmonary Pathology: Need to Redefine Bronchial Dilatation

The radiologic definition of airway dilatation and bronchiectasis in children has substantial limitations. Bronchoarterial (BA) ratio is a commonly used criterion to define airway dilatation despite the lack of normative pediatric data. The objective of our study was to determine the range of normal bronchial to accompanying arterial diameter ratio on high-resolution CT scan of the chest in children and compare it with the available adult data. Children undergoing multidetector CT scan of the chest for nonpulmonary conditions at a single center were prospectively identified. High-resolution reconstruction was performed on those included and both airway lumen and vessel diameters were measured in the upper and lower lobes of both lungs. Mean BA ratio was calculated for each included child, and its correlation with age was assessed. Forty-one children were included; the mean (SD) BA ratio was 0.626 (0.068) (range, 0.437-0.739). This ratio was lower than comparable adult data (combined mean [SD], 0.676 [0.12]; P = .01). No correlation was found with age in our cohort (r = -0.21, P = .19). There was no difference in the ratio based on laterality or lobe. In the pediatric age group, the airway is significantly smaller than the adjoining vessel. Using the radiologic criteria of BA ratio > 1 to define bronchial dilatation would underestimate the presence and extent of bronchiectasis, leading to delayed and missed diagnosis. This highlights the need to redefine the criteria for bronchial dilatation in children.

The reorganization of root anatomy and ultrastructure of syncytial cells in tomato (Lycopersicon esculentum Mill.) infected with potato cyst nematode (Globodera rostochiensis Woll.)

The sequence of anatomical and ultrastructural events leading to the syncytium development in tomato roots infected with <em>Globodera rostochiensis</em> was examined. The syncytia were preferentially induced in cortical or pericyclic cells in the elongation zone of root. They developed towards the vascular cylinder by incorporation of new cells via local cell wall breakdown. After surrounding primary phloem bundle and reaching xylem tracheary elements syncytia spread along vascular cylinder. Roots in primary state of growth seemed to be the best place for syncytium induction as syncytia formed in the zone of secondary growth were less hypertrophied. At the ultrastructural level syncytial elements were characterized by strong hypertrophy, breakdown of central vacuole, increased volume of cytoplasm, proliferation of organelles, and enlargement of nuclei. On the syncytial wall adjoining vessels the cell wall ingrowths were formed, while the syncytial walls at interface of phloem were considerably thickened. They lacked of functional plasmodesmata and did not form any ingrowths. Using immunofluorescent-labelling and immunogold-labelling methods tomato expansin 5 protein was localized in nematode infected roots. The distribution of LeEXP A5 was restricted only to the walls of syncytia. The protein distribution pattern indicated that LeEXP A5 could mediates cell wall expansion during hypertrophy of syncytial elements.

Thoracic Outlet Syndrome Caused by a Pseudoaneurysm After Pseudarthrosis of the Clavicle.

Clavicle fractures are common, with the majority treated conservatively. If treated conservatively, pseudarthrosis of the clavicle is reported in up to 3% of the cases. In rare cases, pseudarthrosis of the clavicle may cause pseudoaneurysm formation, resulting in compression of the brachial plexus and the adjoining vessels, which may produce neurological symptoms and circulatory disorders. Here, we describe two cases of the late onset of pseudoaneurysm formation after pseudarthrosis of the clavicle. Both cases were remarkable because they showed clinical symptoms of TOS. Therefore, surgical treatment was performed and included claviculectomy, resection of the pseudoaneurysm and interposition grafting with an artificial prosthesis. One year after the operation, both patients showed excellent upper extremity function without any deficit of vascular, sensorial or motorial function. Patient's history and radiological findings are the keys to diagnosis. Without treatment, the prognosis is poor with spontaneous development of bleeding or gangrene. Therefore, surgical treatment has to be performed, especially when neurological symptoms occur.

Do xylem fibers affect vessel cavitation resistance?

Possible mechanical and hydraulic costs to increased cavitation resistance were examined among six co-occurring species of chaparral shrubs in southern California. We measured cavitation resistance (xylem pressure at 50% loss of hydraulic conductivity), seasonal low pressure potential (P(min)), xylem conductive efficiency (specific conductivity), mechanical strength of stems (modulus of elasticity and modulus of rupture), and xylem density. At the cellular level, we measured vessel and fiber wall thickness and lumen diameter, transverse fiber wall and total lumen area, and estimated vessel implosion resistance using (t/b)(h)(2), where t is the thickness of adjoining vessel walls and b is the vessel lumen diameter. Increased cavitation resistance was correlated with increased mechanical strength (r(2) = 0.74 and 0.76 for modulus of elasticity and modulus of rupture, respectively), xylem density (r(2) = 0.88), and P(min) (r(2) = 0.96). In contrast, cavitation resistance and P(min) were not correlated with decreased specific conductivity, suggesting no tradeoff between these traits. At the cellular level, increased cavitation resistance was correlated with increased (t/b)(h)(2) (r(2) = 0.95), increased transverse fiber wall area (r(2) = 0.89), and decreased fiber lumen area (r(2) = 0.76). To our knowledge, the correlation between cavitation resistance and fiber wall area has not been shown previously and suggests a mechanical role for fibers in cavitation resistance. Fiber efficacy in prevention of vessel implosion, defined as inward bending or collapse of vessels, is discussed.

A history of diabetes mellitus or how a disease of the kidneys evolved into a kidney disease

Diabetes mellitus has a long history during which it was considered to be a disease of the kidneys well into the middle of the 19th century. Recognized in antiquity from its excessive urine output and described as a disease of the urinary tract, its clinical features and fatal outcome were quite accurately recorded by the 1st century ad . Galen (129-200) described it as a disease specific to the kidneys because of a weakness in their retentive faculties. The sweet taste of diabetic urine, which is described in ancient Indian texts and noted by Avicenna (980-1037) and Morgagni (1635-1683), was attributed to the passage of absorbed water and nutrients unchanged into the urine. In 1674, Thomas Willis (1621-1675) first differentiated diabetes from other causes of polyuria by the sweet taste (quasi melle) of diabetic urine and suggested that the sweetness first appears in the blood. A century later, Matthew Dobson (1732-1784) showed that the urine sweetness was because of sugar and was preceded and accompanied by sugar in the blood. Although diabetes then came to be ascribed to increased sugar in the blood, the presence of sugar in the urine continued to be attributed to the decreased retentive properties of the kidneys. The experimental production of diabetes in pancreatectomized dogs that could be reversed by subcutaneous pancreatic transplantation in 1889, and ultimate isolation of insulin in 1922 clearly established diabetes as an endocrine disease. The stage of diabetes as a disease of the kidneys was now over but that of diabetes as a cause of kidney disease was yet to come. Diabetes as a cause of end stage kidney disease was first described in 1936 and extensively documented shortly thereafter, whereas the evidence of its increasing prevalence as a cause of chronic kidney disease continues to accrue.

Unique vascular morphology of the fourth aortic arches: possible implications for pathogenesis of type-B aortic arch interruption and anomalous right subclavian artery.

Neural crest-derived cells were previously shown to participate in vessel wall formation of the great thoracic arteries, and their contribution was proposed to affect morphology and physiology of these vessels in the chick. The present investigation was undertaken to examine vascular differentiation and morphogenesis of the neural crest-derived aortic arches in mammals. Using immunohistochemical markers for smooth muscle cell differentiation and a neurofilament marker, we examined morphogenesis of the great arteries in mice, ranging from embryonic day 11.5 to the adult. We observed that in the 4th aortic arch arteries early media formation differed from the other arteries, in that they almost completely lacked (or showed decreased) actin expression in certain areas. This discontinuity in actin expression persisted throughout much of foetal development, in the form of circular segments of cells displaying decreased staining for smooth muscle markers, both at the left and right side of the arterial tree. In adult mice, the 4th arch artery derivatives, segment B of the aortic arch and the proximal right subclavian artery, were observed to differ from adjoining vessels in their smooth muscle and elastic composition. Staining for neurofilaments revealed close association of the developing segments with apparent sensory afferent vascular innervation. The unique areas of the 4th arch artery identified here reflect the basic segmental patterning of the early embryonic pharyngeal arches. These segments correlate with sites that are predisposed to interruption or severe hypoplasia, and may thus reveal part of the aetiology of type-B aortic arch interruptions and arteria lusoria.

The Differentiation of Contact Cells and Isolation Cells in the Xylem Ray Parenchyma of Populus maximowiczii

A histochemical analysis was made of the differentiation of contact cells and isolation cells in the xylem ray parenchyma of Populus maximowiczii. The contact cells formed secondary walls at approximately the same time as adjoining vessel elements. The lignification of the cell walls of contact cells and vessel elements began earlier than that of wood fibres and isolation cells. Thus, the formation of the secondary wall, including lignification, of the contact cells might occur at the same time as that of the vessel elements to which they are directly connected. By contrast, the isolation cells began to form secondary walls later than the vessel elements and wood fibres in the vicinity of the isolation cells. After the deposition of the secondary wall, a protective layer was formed in contact cells but no isotropic layer was observed in isolation cells. The results suggest the importance of vessel elements in the determination of the differentiation of adjoining ray parenchyma cells.

An Experimental Model for the Acute and Chronic Evaluation of Intra-Aneurysmal Pressure

Purpose:To develop an animal model for the acute and chronic monitoring of pressure within abdominal aortic aneurysms (AAAs) to be treated with endovascular grafts.Methods:A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Prosthetic aneurysms were implanted into 17 canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasive forelimb sphygmomanometry for 2 weeks. After this time, an intravascular manometer catheter was passed into the aneurysm. Simultaneous pressure measurements were obtained using the implanted strain-gauge pressure transducer, the manometer catheter, and the forelimb sphygmomanometer. Angiography was performed to assess intraluminal morphology, aneurysm anastomoses, and adjoining aortic vessels. In addition, two control animals underwent intra-aneurysmal pressure monitoring after standard surgical aneurysm repair.Results:There was excellent correlation (r = 0.97) between the pressure measurements obtained with the implanted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gauge transducer and the forelimb sphygmomanometer (r = 0.88) during postprocedural monitoring. Intra-aneurysmal pressure was lowered dramatically by surgical exclusion (aneurysm: 15/5 ± 7/4 mmHg; systemic: 124/66 ± 34/17 mmHg; p < 0.001). The prosthetic aneurysms were successfully imaged with angiography.Conclusions:This animal model provides an accurate and reproducible means for measuring intra-aneurysmal pressure on an acute and chronic basis. It may be possible to use this model in the assessment of endovascular devices to determine their efficacy in reducing intra-aneurysmal pressure. Evaluation of complications associated with their use, such as patent aneurysm side branches, perigraft channels, and perianastomotic reflux, may also be possible.

Arterial supply of forearm bones and its importance for the operative treatment of fractures

The operative exposure of a fracture in an osteosynthesis causes disturbances in the blood supply, which often leads to a prolonged process of healing or even to healing problems, a fracture non-union, which is frequently located at the forearm. In order to damage the supplying vessels as little as possible, the position, direction and penetration of the arteries of radius and ulna are demonstrated and systematised in this study. Near the elbow arteries, coming from large adjoining vessels, penetrate the area of the capsular insertion. The nutrient arteries enter both bones in the second proximal quarter of diaphysis, at the radius from anterior to medial, at the ulna from anterior to anteroradial. Small vessels, which penetrate closely proximal to the articular surface in order to supply the distal forearm bones, come from an anastomosis between the radial, the interosseous and the ulnar arteries. In this study access vessels, choice and position of implants will be discussed.

Dirofilaria immitis: Experimental Infections in the Ferret (Mustela putorius furo)

The ferret, Mustela putorius furo, was found to be susceptible to Dirofilaria immitis infection when exposed to low (14) or high (280-420) numbers of infective larvae harvested from Aedes aegypti. Eight ferrets (half of them cortisonized) were inoculated subcutaneously with 14 larvae each. All of them were subsequently found to harbor D. immitis in the heart, and all but one of them had worms of both sexes. Six of these ferrets were examined for microfilaremia at 31 to 35 weeks after inoculation; 3 were positive (one observed only at postmortem examination) and there was evidence that fertilization of female worms had occurred in one other. Females up to 25.5 cm and males up to 16.0 cm were recovered. There was no evidence that the cortisonization of some ferrets had affected the infections. Both male and female ferrets became infected. Four cortisonized ferrets were inoculated with 280 or 420 larvae of D. immitis (divided equally between subcutaneous and intraperitoneal routes). All of them died 16 to 18 weeks after inoculation, yielding 102 to 125 immature D. immitis. In these lethal infections, worms were recovered from the heart and adjoining vessels, and also from vascular and extravascular sites throughout the body.

The Uptake of Nitrate byLolium perennefrom Flowing Nutrient Solution

Experiments with simulated swards of perennial ryegrass (Lolium perenne L.) grown in flowing nutrient solution with NOj held at 0-1 mg N l-1 show that the rate of NOj uptake was related to diurnal, day-to-day, and seasonal changes in radiation. In summer the diurnal variation in NO7 uptake ranged from 25 to 50 mg N m 2 h-1 and the day-to-day variation ranged from 500 to 1500 mg N m~2 d_1. Mean daily rates of uptake over 12 d periods in summer and in winter averaged 908 and 44 mg N m~2, respectively. The pattern of NO7 uptake followed that of C02 flux with the maximum rate of the former occurring 5 or 6 h after the maximum CO, influx. After defoliation, NOj uptake was severely curtailed for 2 d concomitant with a very small influx of C02. Analysis of the changes that occurred in the rate of NOj uptake immediately after the switching on or off of artificial light suggests that two reversible processes may be involved in the relation between NOj uptake and radiation, one with a longer and the other with a shorter time constant. INTRODUCTION It is widely recognized that nutrient uptake by the roots of plants is regulated by the activity of the shoots (Hatrick and Bowling, 1973). Detailed information on the effects of light on nutrient uptake has, however, mostly been derived from experiments with algae and other simple plants (Raven, 1971), and some of the work on the uptake of nutrients by higher plants has involved the use of roots excised from the shoots. The results from such experiments, although difficult to apply quantitatively to field situations, show that the effects of light and of the activity of the shoots may be large and of significance in relation to the uptake of NO J by crops. There follows an account of three experiments with simulated swards of perennial ryegrass grown in a system of flowing solution culture by means of which it was possible to monitor the uptake of NOy by the plants from solution with NOy concentration and pH held nearly constant. These experiments comprised studies of the immediate and the longer term effects of variation in light 1 The Grassland Research Institute is financed through the Agricultural Research Council. This content downloaded from 157.55.39.72 on Thu, 15 Sep 2016 06:19:53 UTC All use subject to http://about.jstor.org/terms 1174 Clement, Hopper, Jones, and Leafe—Nitrate Uptake by L. perenne and of partial defoliation upon NOy uptake; aspects of the relationship between NOy uptake and C02 flux were also examined. MATERIALS AND METHODS Three experiments were conducted with simulated swards of perennial ryegrass (Lolium perenne L. cv. S23) grown in a system of flowing solution culture as previously described (Clement, Hopper, and Jones, 1978). In experiment 1, seed was sown on 4 April and studies of NOy uptake in relation to radiation and of uptake in relation to C02 flux were conducted during June. In experiment 2, seed was sown on 26 April and similar studies were conducted during June and July. In experiment 3, seed was sown on 18 October and studies of NOy uptake in relation to radiation were conducted during November to January. The effects of defoliation were studied in experiments 2 and 3. The plant culture units, each comprising 24 culture vessels giving a simulated sward of 0-8m2, were situated in a south-facing glasshouse with air temperature controlled at approximately 25 °C day, 15 °C night. Experiments 1 and 2 were conducted in natural light only, whereas in experiment 3 artificial as well as natural light was used for certain studies. Radiation from natural light was measured using a Kipp solarimeter. Artificial light from a 2 kW mercury halide lamp (Philips HPI/T) mounted 2 m above the plants in alight tube lined with aluminized film (Silver polyester KS 80/151) gave approximately 6-25 MJ m~2 d_1 during a photoperiod of 9 h. In all experiments the concentration of NOy in the nutrient solution was recorded at intervals of 10 min and held near constant at 0-1 mg N 1~', i.e. 7-14 ,uM, by means of the ion monitoring and control assembly as previously described (Clement, Hopper, Canaway, and Jones, 1974). In experiments 1 and 2, NOy uptake and C02 flux were measured concomitantly for periods of 3 d. For this purpose all plants were removed except those growing in nine adjoining vessels of a plant culture unit. The remaining sward (0-25 m2) was covered by a 500 mm x 500 mm trans parent plastic film enclosure (see Plate 1) and C02 flux measured using an apparatus described by Stiles and Leafe (1970) and Stiles (1977).

Scalariform Perforation Plate Development in Laurelia novae-zelandiae A. Cunn. : A Scanning Electron Microscope Study

The development of the scalariform perforation plates in Laurelia novae- zelandiae A. Cunn. is described and illustrated with scanning electron micrographs. The primary walls and middle lamella in the areas to be perforated remain intact late in the differentiation of .the adjoining vessel members. After the secondary wall has beenlaid down on other areas of the vessel member walls, the perforation partitions are broken down by an enzymatic action on the surface of the partitions. This process leaves a network of fibrils which later disappear, possibly by the action of the transpiration stream.

Perforation Plate Development in Knightia excelsa R. Br. : A Scanning Electron Microscope Study

The development of perforation plates in the vessels of Knightia excelsa R. Br. is described. The primary walls and middle lamella in the region of the perforation remain intact late in the differentiation of the adjoining vessel members. Only after the secondary wall has been laid down, forming prominent borders over this perforation partition, does the latter show any sign of degeneration. The breakdown process involves a change in the nature of the partition, which becomes granular in appearance. Small holes then develop in it before its final disappearance.

Unusual perforation plates: observations using scanning electron microscopy

Mis-matching and intermediate perforation plates in the vessels of a number of woods are illustrated by scanning electron micrographs. Examples illustrated include simple to scalariform and scalariform to foraminate combination perforation plates, forms intermediate between the simple and scalariform types and mis-matching scalariform perforation plates where the dividing bars of one cell are at an angle to those in the adjoining vessel member.

Heartwood stain in red oak

The paper describes the appearance, properties, and ultrastructure of red oak heartwood containing dark discolorations. The possible cause and origin of discoloration are discussed, although the etiology of the stain is not explicit. It was found that the heartwood stain moves from ray parenchyma to adjoining vessels, fibers, and tracheids by the pit membranes and plasmodesmata. It appears that there may be extended openings in the pit membrane which may facilitate the movement of materials through such a specialized filamentous structure. Internal checking or honeycomb as an indirect result of the discoloring material is mentioned.