Search results for "Vessel"

Simplified Procedure to Evaluate Head Losses in Drip Irrigation Laterals

2005

The lateral lines of a drip irrigation system consist of pressurized pipelines with inline or online emitters. Proper hydraulic design of drip laterals usually requires the accurate evaluation of the total head losses, represented by friction losses along the pipe and the emitters, and local losses due to the emitter connections. This paper extends the local loss evaluation procedure, previously obtained for coextruded laterals, on the basis of new experiments. In addition, a simplified procedure was proposed based on the constant outlet discharge assumption for a quick evaluation of total head losses in drip irrigation lines, taking into account the total local loss due to the emitter conn…

Experimental Analysis of Local Pressure Losses for Microirrigation Laterals

2004

The accurate design of drip irrigation laterals needs to consider the variation of hydraulic head due to pipe elevation changes, head losses along the lines, and also, at a given operating pressure, emitter discharge variations related to manufacturing variability, clogging, and water temperature. Hydraulic head variations are consequent to both the friction losses and local losses due to the in-line or on-line emitters along the pipe, which determine the contraction and subsequent enlargement of the flow streamlines. Moreover, in-line emitters usually have a smaller diameter than the pipe, and therefore an additional friction loss must be considered. Evaluation of energy losses and consequ…

Transient reduction of the ocular perfusion pressure and the oscillatory potentials of the ERG

2005

Abstract Purpose. To evaluate the changes of the Oscillatory Potentials (OPs) of Electroretinogram (ERG) caused by short-term hypertension in human subjects, and their relationship with ocular perfusion pressure (OPP). Methods. Suction cup technique in 12 normal volunteers with OPs simultaneously recording. Results. Scotopic and photopic OPs were altered during OPP drop. Scotopic OPs showed more sensitiveness, with higher reduction (from 21% to 47%), when compared to the basal value, than in photopic recordings (from 14% to 34%). In both conditions, the relationship between OPP and OPs presented a steady amplitude before the trough after the +30 step, and rapid recovery after OPP normalisat…

Apoptosis causes lumen formation during angiogenesis in vitro.

2002

Paraoxonase-2 Reduces Oxidative Stress in Vascular Cells and Decreases Endoplasmic Reticulum Stress–Induced Caspase Activation

2007

Background— In the vascular system, elevated levels of reactive oxygen species (ROS) produce oxidative stress and predispose to the development of atherosclerosis. Therefore, it is important to understand the systems producing and those scavenging vascular ROS. Here, we analyzed the ROS-reducing capability of paraoxonase-2 (PON2) in different vascular cells and its involvement in the endoplasmic reticulum stress pathway known as the unfolded protein response. Methods and Results— Quantitative real-time polymerase chain reaction and Western blotting revealed that PON2 is equally expressed in vascular cells and appears in 2 distinct glycosylated isoforms. By determining intracellular ROS, we…

Sample Preparation for Mass-spectrometry-based Proteomics Analysis of Ocular Microvessels

2019

The use of isolated ocular blood vessels in vitro to decipher the pathophysiological state of the eye using advanced technological approaches has greatly expanded our understanding of certain diseases. Mass spectrometry (MS)-based proteomics has emerged as a powerful tool to unravel alterations in the molecular mechanisms and protein signaling pathways in the vascular beds in health and disease. However, sample preparation steps prior to MS analyses are crucial to obtain reproducible results and in-depth elucidation of the complex proteome. This is particularly important for preparation of ocular microvessels, where the amount of sample available for analyses is often limited and thus, pose…

Giant bronchogenic cyst within the aortic wall mimicking symptoms of acute type A aortic dissection.

2010

Mediastinal lymph node staging with transesophageal echography in cancer of the lung.

1990

Transesophageal echography (TEE) was used prospectively to study mediastinal lymph node enlargement in 23 patients with cancer of the lung. The findings were validated blindly by comparison with computed tomography (CT, n = 23) and pathological N classification after curative surgery (n = 9). Lymph nodes larger than 1 cm were defined as pathologically enlarged. In the upper mediastinum, 22% (8 vs 36), in the lower mediastinum including the subaortic region 112% (37 vs 33) and in the hilar region 67% (6 vs 9) of enlarged lymph nodes diagnosed by CT were detected by TEE. A pathological study in 9 patients demonstrated true positive findings in 2 vs 1, true negatives in 4 vs 5, false positives…

New 3-zone hybrid graft : First-in-man experience in acute type I dissection

2019

Abstract Objective Acute type I aortic dissection (AAD) represents a surgical emergency with time-dependent evolving complications. Frozen elephant trunk (FET) enables false lumen exclusion downstream but is still debated in AAD due to its greater dimension of surgery. To combine the benefits of fast proximal repair with the FET benefits, a 3-zone hybrid graft was developed consisting of an ascending polyester portion, an arch noncovered stent, and a descending stent graft. Mid-term results of this new technique are presented. Methods A total of 6 patients (age mean 69 years) with type I AAD in critical status (Penn classification B n = 5, BC n = 1) were operated between July 2016 and April…

Symptomatic atherosclerotic occlusive disease of all supra-aortic arch vessels treated with total aortic arch rerouting.

2011

We present an uncommon case of symptomatic atherosclerotic occlusive disease of all supra-aortic arch vessels and its surgical treatment by total aortic arch rerouting after endarteriectomy of all target vessels.