Continuous arterio-venous haemodiafiltration: hydraulic and diffusive permeability index of an AN-69 capillary haemofilter

1998 ◽  
Vol 36 (1) ◽  
pp. 43-50
Author(s):  
E. Akcahuseyin ◽  
W. A. van Duyl ◽  
H. H. Vincent ◽  
M. C. Vos ◽  
M. A. D. H. Schalekamp
Keyword(s):  
Permeability Index ◽  
Diffusive Permeability

Permeability to albumin in isolated coronary venules

1993 ◽  
Vol 265 (2) ◽  
pp. H543-H552 ◽  
Author(s):  
Y. Yuan ◽  
W. M. Chilian ◽  
H. J. Granger ◽  
D. C. Zawieja
Keyword(s):  
Permeability Coefficient ◽  
Filtration Rate ◽  
Intraluminal Pressure ◽  
Apparent Permeability ◽  
Filtration Pressure ◽  
Diffusive Permeability ◽  
Apparent Permeability Coefficient ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Intravascular Pressure

This study reports measurements of albumin permeability in isolated coronary venules. The isolated microvessel technique allows the quantification of transmural exchange of macromolecules under tightly controlled physical and chemical conditions. Transvenular exchange of albumin was studied in isolated coronary venules during alterations in filtration rate caused by changes in intravascular pressure. The apparent permeability coefficient of albumin (Pa) at an intraluminal pressure of 11 cmH2O was 3.92 +/- 0.43 x 10(-6) cm/s. Elevating intraluminal pressure to 16 and 21 cmH2O increased Pa to 5.13 +/- 0.57 x 10(-6) and 6.78 +/- 0.66 x 10(-6) cm/s, respectively. Calculation of the true diffusive permeability coefficient of albumin (Pd) at zero filtration rate was 1.54 x 10(-6) cm/s. The product of hydraulic conductance (Lp) and (1 - sigma), where sigma is the solute reflection coefficient, was 3.25 x 10(-7) cm.s-1 x cmH2O-1. At a net filtration pressure of 4-5 cmH2O, diffusion accounts for > 60% of total albumin transport across the venular wall. Transmural albumin flux is very sensitive to filtration rate, rising 6.7% for each cmH2O elevation of net filtration pressure. At 11 cmH2O net filtration pressure, convection accounts for nearly 70% of net albumin extravasation from the venular lumen. We suggest that the isolated coronary venule is a suitable preparation for the study of solute exchange in the heart.

scholarly journals CT Simplified Radiomic Approach to Assess the Metastatic Ductal Adenocarcinoma of the Pancreas

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1843
Author(s):  
Mirko D’Onofrio ◽  
Riccardo De Robertis ◽  
Gregorio Aluffi ◽  
Camilla Cadore ◽  
Alessandro Beleù ◽  
...  
Keyword(s):  
Pancreatic Ductal Adenocarcinoma ◽  
Ductal Adenocarcinoma ◽  
Newly Diagnosed ◽  
Inclusion Criteria ◽  
Permeability Index ◽  
Metastatic Tumors ◽  
Qualitative And Quantitative ◽  
Portal Phase ◽  
Phase Images ◽  
Adenocarcinoma Of The Pancreas

The aim of this study was to perform a simplified radiomic analysis of pancreatic ductal adenocarcinoma based on qualitative and quantitative tumor features and to compare the results between metastatic and non-metastatic patients. A search of our radiological, surgical, and pathological databases identified 1218 patients with a newly diagnosed pancreatic ductal adenocarcinoma who were referred to our Institution between January 2014 and December 2018. Computed Tomography (CT) examinations were reviewed analyzing qualitative and quantitative features. Two hundred eighty-eight patients fulfilled the inclusion criteria and were included in this study. Overall, metastases were present at diagnosis in 86/288 patients, while no metastases were identified in 202/288 patients. Ill-defined margins and a hypodense appearance on portal-phase images were significantly more common among patients with metastases compared to non-metastatic patients (p < 0.05). Metastatic tumors showed a significantly larger size and significantly lower arterial index, perfusion index, and permeability index compared to non-metastatic tumors (p < 0.05). In the management of pancreatic ductal adenocarcinoma, early detection and correct staging are key elements. The study of computerized tomography characteristics of pancreatic ductal adenocarcinoma showed substantial differences, both qualitative and quantitative, between metastatic and non-metastatic disease.

Tight Jurassic Carbonate Reservoir Characterization and Fluid Typing Identification by Integrating Magnetic Resonance, Elemental Spectroscopy and Micro-Resistivity Image Data in Umm Ross Field, West Kuwait, Case Study

2021 ◽  
Author(s):  
Said Beshry Mohamed ◽  
Sherif Ali ◽  
Mahmoud Fawzy Fahmy ◽  
Fawaz Al-Saqran
Keyword(s):  
Magnetic Resonance ◽  
Reservoir Characterization ◽  
Clay Content ◽  
Effective Porosity ◽  
Carbonate Reservoir ◽  
High Resistivity ◽  
Permeability Index ◽  
Rock Quality ◽  
Porosity And Permeability ◽  
Bulk Volume

Abstract The Middle Marrat reservoir of Jurassic age is a tight carbonate reservoir with vertical and horizontal heterogeneous properties. The variation in lithology, vertical and horizontal facies distribution lead to complicated reservoir characterization which lead to unexpected production behavior between wells in the same reservoir. Marrat reservoir characterization by conventional logging tools is a challenging task because of its low clay content and high-resistivity responses. The low clay content in Marrat reservoirs gives low gamma ray counts, which makes reservoir layer identification difficult. Additionally, high resistivity responses in the pay zones, coupled with the tight layering make production sweet spot identification challenging. To overcome these challenges, integration of data from advanced logging tools like Sidewall Magnetic Resonance (SMR), Geochemical Spectroscopy Tool (GST) and Electrical Borehole Image (EBI) supplied a definitive reservoir characterization and fluid typing of this Tight Jurassic Carbonate (Marrat formation). The Sidewall Magnetic resonance (SMR) tool multi wait time enabled T2 polarization to differentiate between moveable water and hydrocarbons. After acquisition, the standard deliverables were porosity, the effective porosity ratio, and the permeability index to evaluate the rock qualities. Porosity was divided into clay-bound water (CBW), bulk-volume irreducible (BVI) and bulk-volume moveable (BVM). Rock quality was interpreted and classified based on effective porosity and permeability index ratios. The ratio where a steeper gradient was interpreted as high flow zones, a gentle gradient as low flow zones, and a flat gradient was considered as tight baffle zones. SMR logging proved to be essential for the proper reservoir characterization and to support critical decisions on well completion design. Fundamental rock quality and permeability profile were supplied by SMR. Oil saturation was identified by applying 2D-NMR methods, T1/T2 vs. T2 and Diffusion vs. T2 maps in a challenging oil-based mud environment. The Electrical Borehole imaging (EBI) was used to identify fracture types and establish fracture density. Additionally, the impact of fractures to enhance porosity and permeability was possible. The Geochemical Spectroscopy Tool (GST) for the precise determination of formation chemistry, mineralogy, and lithology, as well as the identification of total organic carbon (TOC). The integration of the EBI, GST and SMR datasets provided sweet spots identification and perforation interval selection candidates, which the producer used to bring wells onto production.

scholarly journals SuitabilityAssessment of Sirsa River Water for irrigation in Shiwalik Foothills of North Western Himalaya

2019 ◽  
Vol 14 (1) ◽  
pp. 159-169
Author(s):  
S.K. Bhardwaj ◽  
R. Sharma ◽  
R.K. Aggarwal
Keyword(s):  
River Water ◽  
Western Himalaya ◽  
Quality Parameters ◽  
Sodium Adsorption Ratio ◽  
Permeability Index ◽  
Magnesium Hazard ◽  
Water Ph ◽  
Kelly’S Ratio ◽  
Sirsa River ◽  
North Western

Sirsa river runs through the central part of the Baddi Barotiwala Nalagarh (BBN) industrial region in district Solan of Himachal Pradesh. The water of this river is used for irrigating agricultural fields by the farmers. The increased industrial and urbanization activities in the valley are being pointed out as the cause of river water pollution by the farmers and other habitations in the region. Therefore, such reports prompted the idea to conduct this study to assess the river water suitability for irrigational commitments. Thus, Sirsa river water quality was assessed during the year 2018 by taking seven sampling sites as treatments which were replicated six times. To assess the suitability of Sirsa river water for irrigation purposes, various quality parameters such as pH, Electrical Conductivity (EC), Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), Residual Sodium Carbonate (RSC), Permeability Index (PI), Kelly’s Ratio (KR), Magnesium Hazard (Mg. Haz.)and Chloro-Alkaline Index (CAI) were determined. In the Sirsa river water pH, EC,RSC,SSP,SAR,PI,KR,Mg Hazand CAI were found in the range of 6.64-7.55, 129.50-719.67 µS/cm, -5.27 - -2.18 meq/l, 13.49-49.44%, 0.41-4.00%, 28.20-57.89%, 2.94-21.24%, 14.97-37.83%and 0.04-0.58%, respectively. All the factors were within the safe range for irrigation purposes except KR values. The high KR values above unity pointed out towards sodicity hazard of water which, therefore can not be used for irrigation purposes.

Test of a two-pathway model for small-solute exchange across the capillary wall

1998 ◽  
Vol 274 (6) ◽  
pp. H2062-H2073 ◽  
Author(s):  
B. M. Fu ◽  
R. H. Adamson ◽  
F. E. Curry
Keyword(s):  
Tight Junctions ◽  
Sodium Fluorescein ◽  
Intracellular Camp ◽  
Pathway Model ◽  
Mean Values ◽  
Permeability Coefficients ◽  
Diffusive Permeability ◽  
Small Pore ◽  
Separate Pathway ◽  
Small Solute

We previously proposed a two-pathway model for solute and water transport across vascular endothelium (Fu, B. M., R. Tsay, F. E. Curry, and S. Weinbaum. J. Biomech. Eng. 116: 502–513, 1994) that hypothesized the existence of a continuous slit 2 nm wide along tight junction strands within the interendothelial cleft in parallel with 20 × 150-nm breaks in tight junctions. We tested this model by measuring capillary permeability coefficients ( P) to a small solute (sodium fluorescein, radius 0.45 nm), assumed to permeate primarily the 2-nm small pore, and an intermediate-sized solute (FITC-α-lactalbumin, radius 2.01 nm) excluded from the small pore. Mean values of the paired diffusive permeability coefficients, P sodium fluorescein and P FITC-α-lactalbumin, were 34.4 and 2.9 × 10−6 cm/s, respectively, after corrections for solvent drag and free dye ( n = 26). These permeabilities were accounted for by transport through the large-break pathway without the additional capacity of the hypothetical 2-nm pathway. As a further test we examined the relative reductions of P sodium fluorescein and P FITC-α-lactalbuminproduced by elevated intracellular cAMP. Within 20 min after the introduction of rolipram and forskolin, P sodium fluorescein and P FITC-α-lactalbumindecreased to 0.67 and 0.64 times their respective baseline values. These similar responses to permeability decrease were evidence that the two solutes were carried by a common pathway. Combined results in both control and reduced permeability states did not support the hypothesis that a separate pathway across tight junctions is available for solutes with a radius as large as 0.75 nm. If such a pathway is present, then its size must be smaller than that of sodium fluorescein.

Essential fatty acid-deficient rats are resistant to oleic acid-induced pulmonary injury

1989 ◽  
Vol 67 (2) ◽  
pp. 811-816 ◽  
Author(s):  
H. A. Ball ◽  
J. A. Cook ◽  
K. M. Spicer ◽  
W. C. Wise ◽  
P. V. Halushka
Keyword(s):  
Arachidonic Acid ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Bronchoalveolar Lavage ◽  
Essential Fatty Acid ◽  
Lavage Fluid ◽  
Permeability Index ◽  
Essential Fatty Acid Deficient ◽  
Fluid Levels ◽  
Pulmonary Permeability

Because leukotrienes and prostaglandins are inflammatory mediators derived from arachidonic acid, their potential role in oleic acid-induced lung injury was evaluated in control and in essential fatty acid-deficient (EFAD) rats depleted of arachidonic acid substrate. In control rats, oleic acid (0.06 ml/kg iv) increased the pulmonary permeability index (measured by scintigraphy) from -10 +/- 13 x 10(-6) s-1 to 217 +/- 20 x 10(-6) s-1 and 118 +/- 13 x 10(-6) s-1 at 5 and 50 min (P less than 0.05), respectively. It also caused arterial hypoxemia at 30 min (P less than 0.05). Compared with saline controls, oleic acid increased bronchoalveolar lavage fluid levels of immunoreactive (i) LTC4/D4, iLTB4, (P less than 0.01), and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) (P less than 0.05). In EFAD rats, oleic acid failed to significantly increase the lung permeability index at 5 and 50 min. In contrast to control rats, oleic acid failed to cause hypoxemia in the EFAD rats. Bronchoalveolar lavage levels of iLTB4 and i6-keto-PGF1 alpha after oleic acid in EFAD rats were lower compared with oleic acid controls, whereas iLTC4/D4 in the oleic acid EFAD group was not decreased. Treatment with intraperitoneal ethyl arachidonate (400 mg over 2 wk) reversed the resistance of EFAD rats such that the pulmonary edema (P less than 0.05) was evident after oleic acid. This latter group also manifested a significant (P less than 0.05) rise in the bronchoalveolar lavage levels of iLTB4 and i6-keto-PGF1 alpha. These results suggest that arachidonic acid metabolites contribute to oleic acid-induced pulmonary permeability.

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