scholarly journals Quantitative MRI Provides Markers Of Intra-, Inter-Regional, And Age-Related Differences In Young Adult Cortical Microstructure

2017 ◽  
Author(s):  
Daniel Carey ◽  
Francesco Caprini ◽  
Micah Allen ◽  
Antoine Lutti ◽  
Nikolaus Weiskopf ◽  
...  
Keyword(s):  
Young Adult ◽  
Water Content ◽  
Developmental Change ◽  
Free Water ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Quantitative Mr ◽  
Age Related ◽  
Cortical Regions ◽  
Macromolecular Content

Measuring the structural composition of the cortex is critical to understanding typical development, yet few investigations in humans have charted markers in vivo that are sensitive to tissue microstructural attributes. Here, we used a well-validated quantitative MR protocol to measure four parameters (R1, MT, R2*, PD*) that differ in their sensitivity to facets of the tissue microstructural environment (R1, MT: myelin, macromolecular content; R2*: paramagnetic ions, i.e., iron; PD*: free water content). Mapping these parameters across cortical regions in a young adult cohort (18-30 years, N=93) revealed expected patterns of increased macromolecular content as well as reduced tissue water content in primary and primary adjacent cortical regions. Mapping across cortical depth within regions showed decreased expression of myelin and related processes - but increased tissue water content - when progressing from the grey/white to the grey/pial boundary, in all regions. Charting developmental change in cortical microstructure, we found that parameters with the greatest sensitivity to tissue myelin (R1 & MT) showed linear increases with age across frontal and parietal cortex (change 0.5-1.0% per year). Overlap of robust age effects for both parameters emerged in left inferior frontal, right parietal and bilateral pre-central regions. Our findings afford an improved understanding of ontogeny in early adulthood and offer normative quantitative MR data for inter- and intra-cortical composition, which may be used as benchmarks in further studies.

scholarly journals Isoflurane in Contrast to Propofol Promotes Fluid Extravasation during Cardiopulmonary Bypass in Pigs

2013 ◽  
Vol 119 (4) ◽  
pp. 861-870 ◽  
Author(s):  
Hege Kristin Brekke ◽  
Stig Morten Hammersborg ◽  
Steinar Lundemoen ◽  
Arve Mongstad ◽  
Venny Lise Kvalheim ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Water Content ◽  
Interstitial Fluid ◽  
Outcome Analysis ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Edema Formation ◽  
Fluid Extravasation ◽  
Isoflurane Anesthesia ◽  
Total Tissue

Abstract Background: A highly positive intraoperative fluid balance should be prevented as it negatively impacts patient outcome. Analysis of volume-kinetics has identified an increase in interstitial fluid volume after crystalloid fluid loading during isoflurane anesthesia. Isoflurane has also been associated with postoperative hypoxemia and may be associated with an increase in alveolar epithelial permeability, edema formation, and hindered oxygen exchange. In this article, the authors compare fluid extravasation rates before and during cardiopulmonary bypass (CPB) with isoflurane- versus propofol-based anesthesia. Methods: Fourteen pigs underwent 2 h of tepid CPB with propofol (P-group; n = 7) or isoflurane anesthesia (I-group; n = 7). Fluid requirements, plasma volume, colloid osmotic pressures in plasma and interstitial fluid, hematocrit levels, and total tissue water content were recorded, and fluid extravasation rates calculated. Results: Fluid extravasation rates increased in the I-group from the pre-CPB level of 0.27 (0.13) to 0.92 (0.36) ml·kg−1·min−1, but remained essentially unchanged in the P-group with significant between-group differences during CPB (pb = 0.002). The results are supported by corresponding changes in interstitial colloid osmotic pressure and total tissue water content. Conclusions: During CPB, isoflurane, in contrast to propofol, significantly contributes to a general increase in fluid shifts from the intravascular to the interstitial space with edema formation and a possible negative impact on postoperative organ function.

Detection of bark lesions caused by Phytophthoracinnamomi in Eucalyptusmarginata with the plant impedance ratio meter and the Shigometer

1987 ◽  
Vol 17 (10) ◽  
pp. 1228-1233 ◽  
Author(s):  
Joanna T. Tippett ◽  
Joanne L. Barclay
Keyword(s):  
Water Content ◽  
Electrical Resistance ◽  
Water Status ◽  
Healthy Tissue ◽  
Plant Tissues ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Impedance Ratio ◽  
New Instrument ◽  
Electrical Admittance

A new instrument, the plant impedance ratio meter (PIRM), has been used to determine the extent of lesions caused by Phytophthoracinnamomi Rands in Eucalyptusmarginata Sm. The performance of the PIRM, which measures electrical admittance (the inverse of impedance) of plant tissues at two frequencies (from which an impedance ratio is calculated), was evaluated and compared with that of the Shigometer. The electrical admittance measured at 1 and 10 kHz (PIRM) and the electrical resistance (Shigometer) of healthy tissue varied with both the depth of tissue probed and the water status of stems. However, the impedance ratios (calculated from the admittance values) remained relatively constant for healthy tissue and changes were independent of depth of probing. Hence, changes in ratios indicated a change in tissue condition or necrosis rather than changes in either tissue water content or depth of probing. The impedance ratios recorded for healthy bark tissues were consistently higher than those for the P. cinnamomi lesions in E. marginata. Trends in electrical resistance measured across the boundaries of the lesions with the Shigometer were variable depending on lesion age. The PIRM was used successfully to detect P. cinnamomi lesions in E. marinate and lesion fronts were predicted to an accuracy of ± 7.2 mm (n = 150), lesions being up to 1.0 m long at the time stems were harvested.

scholarly journals Algorithm for Mapping Kidney Tissue Water Content during Normothermic Machine Perfusion Using Hyperspectral Imaging

Algorithms ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 289
Author(s):  
Wenke Markgraf ◽  
Jannis Lilienthal ◽  
Philipp Feistel ◽  
Christine Thiele ◽  
Hagen Malberg
Keyword(s):  
Water Content ◽  
Hyperspectral Imaging ◽  
Wavelength Range ◽  
Kidney Tissue ◽  
Reflectance Spectra ◽  
Machine Perfusion ◽  
Least Squares Regression ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Normothermic Machine Perfusion

The preservation of kidneys using normothermic machine perfusion (NMP) prior to transplantation has the potential for predictive evaluation of organ quality. Investigations concerning the quantitative assessment of physiological tissue parameters and their dependence on organ function lack in this context. In this study, hyperspectral imaging (HSI) in the wavelength range of 500–995 nm was conducted for the determination of tissue water content (TWC) in kidneys. The quantitative relationship between spectral data and the reference TWC values was established by partial least squares regression (PLSR). Different preprocessing methods were applied to investigate their influence on predicting the TWC of kidneys. In the full wavelength range, the best models for absorbance and reflectance spectra provided Rp2 values of 0.968 and 0.963, as well as root-mean-square error of prediction (RMSEP) values of 2.016 and 2.155, respectively. Considering an optimal wavelength range (800–980 nm), the best model based on reflectance spectra (Rp2 value of 0.941, RMSEP value of 3.202). Finally, the visualization of TWC distribution in all pixels of kidneys’ HSI image was implemented. The results show the feasibility of HSI for a non-invasively and accurate TWC prediction in kidneys, which could be used in the future to assess the quality of kidneys during the preservation period.

USE OF CONTROLLED ENVIRONMENTS FOR WINTER CEREAL COLD HARDINESS EVALUATION: CONTROLLED FREEZE TESTS AND TISSUE WATER CONTENT AS PREDICTION TESTS

1989 ◽  
Vol 69 (2) ◽  
pp. 355-366 ◽  
Author(s):  
A. L. BRULE-BABEL ◽  
D. B. FOWLER
Keyword(s):  
Water Content ◽  
Cold Acclimation ◽  
Cold Hardiness ◽  
Screening Method ◽  
Strong Relationship ◽  
Winter Rye ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Winter Cereal ◽  
Controlled Environments

Field survival is the most commonly employed method of evaluating the winter hardiness of cereals. However, the inherent difficulties with field trials have stimulated a continued interest in the use of controlled environments and prediction tests for the evaluation of cold hardiness. In the present studies, cold hardiness expression of wheat (Triticum aestivum L.) cultivars acclimated in controlled environments was found to be similar to that reported for field conditions in Saskatchewan, Canada. LT50 and tissue water content measurements on wheat and rye (Secale cereale L.) cultivars acclimated in controlled environments were highly correlated with cultivar field survival ability. Investigation of the relationship between field survival and tissue water content during cold acclimation in controlled environments indicated that, to be effective as a screening method for cold hardiness, measurements of tissue water content should be made on fully acclimated plants for which the acclimation conditions have been rigorously controlled. Level of acclimation was not as critical for cold hardiness screening when LT50 measurements were utilized; however, maximum resolution also required fully acclimated plants. Although a strong relationship (r = −0.80 to −0.89) was found to exist with field survival potential, an inability to detect small, but important, differences without excessive replication would generally restrict the use of LT50 and tissue water content to situations where large homogeneous plant populations were available and only coarse screens for cold hardiness were required.Key words: Cold acclimation, winter wheat, winter rye, cold hardiness, water content, replication

Responses of the moss Tortula ruralis to desiccation treatments. II. Variations in desiccation tolerance

1981 ◽  
Vol 59 (12) ◽  
pp. 2707-2712 ◽  
Author(s):  
Mark W. Schonbeck ◽  
J. Derek Bewley
Keyword(s):  
Water Content ◽  
Desiccation Tolerance ◽  
Dry Weight ◽  
Severe Damage ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Tortula Ruralis

Variations in the apparent desiccation tolerance of the moss Tortula ruralis were traced to several causes. When the moss was kept continuously hydrated for several days, desiccation tolerance tended to decrease ("dehardening"). Conversely, daily episodes of drying and rehydration induced hardening so that the moss could tolerate rapid drying to a tissue water content of 0.008 g∙g dry weight−1.Different clumps of moss showed very different degrees of desiccation tolerance. The least tolerant samples suffered severe damage after rapid drying, whereas the most tolerant suffered little damage, and did not deharden during 3 days continuous hydration.

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