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Tomasella M, Calderan A, Mihelčič A, Petruzzellis F, Braidotti R, Natale S, Lisjak K, Sivilotti P, Nardini A. Best Procedures for Leaf and Stem Water Potential Measurements in Grapevine: Cultivar and Water Status Matter. Plants (Basel) 2023; 12:2412. [PMID: 37446973 DOI: 10.3390/plants12132412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023]
Abstract
The pressure chamber is the most used tool for plant water status monitoring. However, species/cultivar and seasonal effects on protocols for reliable water potential determination have not been properly tested. In four grapevine cultivars and two times of the season (early season, Es; late season, Ls, under moderate drought), we assessed the maximum sample storage time before leaf water potential (Ψleaf) measurements and the minimum equilibration time for stem water potential (Ψstem) determination, taking 24 h leaf cover as control. In 'Pinot gris', Ψleaf already decreased after 1 h leaf storage in both campaigns, dropping by 0.4/0.5 MPa after 3 h, while in 'Refosk', it decreased by 0.1 MPa after 1 and 2 h in Es and Ls, respectively. In 'Merlot' and 'Merlot Kanthus', even 3 h storage did not affect Ψleaf. In Es, the minimum Ψstem equilibration was 1 h for 'Refošk' and 10 min for 'Pinot gris' and 'Merlot'. In Ls, 'Merlot Kanthus' required more than 2 h equilibration, while 1 h to 10 min was sufficient for the other cultivars. The observed cultivar and seasonal differences indicate that the proposed tests should be routinely performed prior to experiments to define ad hoc procedures for water status determination.
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Affiliation(s)
- Martina Tomasella
- Department of Life Sciences, University of Trieste, via L. Giorgieri 10, 34127 Trieste, Italy
| | - Alberto Calderan
- Department of Life Sciences, University of Trieste, via L. Giorgieri 10, 34127 Trieste, Italy
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 206, 33100 Udine, Italy
| | - Alenka Mihelčič
- Department of Fruit Growing, Agricultural Institute of Slovenia, Viticulture and Enology, Hacquetova Ulica 17, SI-1000 Ljubljana, Slovenia
| | - Francesco Petruzzellis
- Department of Life Sciences, University of Trieste, via L. Giorgieri 10, 34127 Trieste, Italy
| | - Riccardo Braidotti
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 206, 33100 Udine, Italy
| | - Sara Natale
- Department of Life Sciences, University of Trieste, via L. Giorgieri 10, 34127 Trieste, Italy
- Department of Biology, University of Padova, Via Ugo Bassi 58B, 35121 Padova, Italy
| | - Klemen Lisjak
- Department of Fruit Growing, Agricultural Institute of Slovenia, Viticulture and Enology, Hacquetova Ulica 17, SI-1000 Ljubljana, Slovenia
| | - Paolo Sivilotti
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 206, 33100 Udine, Italy
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, via L. Giorgieri 10, 34127 Trieste, Italy
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Svare F, Ghosh F. Beneficial and Detrimental Pressure-Related Effects on Inner Neurons in the Adult Porcine In Vitro Retina. Transl Vis Sci Technol 2023; 12:19. [PMID: 36780140 PMCID: PMC9927757 DOI: 10.1167/tvst.12.2.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Purpose To explore pressure-related effects in the adult porcine retina in vitro. Methods Retinal explants were subjected to 0, 10, 30, or 60 mmHg of pressure for 24 or 48 hours in culture. Overall tissue damage in sections was assessed by lactate dehydrogenase media levels, hematoxylin and eosin staining, and TUNEL staining. Inner retinal neurons were evaluated by protein kinase C alpha (rod bipolar cells), CHX10 (overall bipolar cell population), parvalbumin (amacrine cells), and RBPMS (ganglion cells) immunohistochemistry. Results All retinas kept in culture displayed increased pyknosis and apoptosis compared with directly fixed controls. The 10-mmHg explants displayed attenuation of overall tissue damage compared with the 0-, 30-, and 60-mmHg counterparts. No difference in the number of rod bipolar cells was seen in the 10-mmHg explants compared with directly fixed controls, whereas significantly fewer cells were detected in the remaining pressure groups. No difference in the number of ganglion cells in the 0-, 10-, and 60-mmHg groups was seen compared with directly fixed controls after 24 hours, whereas a lower number was found in the 30-mmHg counterpart. A decline of ganglion cells was found in the 0-, 10-, and 60-mmHg group after 48 hours, but no further decrease was seen in the 30-mmHg group. No differences were detected in overall bipolar and amacrine cells in the pressure groups after 24 hours compared with directly fixed controls. Conclusions A moderate amount of pressure attenuates culture-related retinal neurodegeneration. Rod bipolar cells are specifically vulnerable to excessive pressure. Translational Relevance These findings are relevant for glaucoma-related research.
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Affiliation(s)
- Frida Svare
- Department of Ophthalmology, Lund University, Lund, Sweden
| | - Fredrik Ghosh
- Department of Ophthalmology, Lund University, Lund, Sweden
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Rodriguez‐Dominguez CM, Forner A, Martorell S, Choat B, Lopez R, Peters JMR, Pfautsch S, Mayr S, Carins‐Murphy MR, McAdam SAM, Richardson F, Diaz‐Espejo A, Hernandez‐Santana V, Menezes‐Silva PE, Torres‐Ruiz JM, Batz TA, Sack L. Leaf water potential measurements using the pressure chamber: Synthetic testing of assumptions towards best practices for precision and accuracy. Plant Cell Environ 2022; 45:2037-2061. [PMID: 35394651 PMCID: PMC9322401 DOI: 10.1111/pce.14330] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/21/2022] [Accepted: 03/26/2022] [Indexed: 05/24/2023]
Abstract
Leaf water potential (ψleaf ), typically measured using the pressure chamber, is the most important metric of plant water status, providing high theoretical value and information content for multiple applications in quantifying critical physiological processes including drought responses. Pressure chamber measurements of ψleaf (ψleafPC ) are most typical, yet, the practical complexity of the technique and of the underlying theory has led to ambiguous understanding of the conditions to optimize measurements. Consequently, specific techniques and precautions diversified across the global research community, raising questions of reliability and repeatability. Here, we surveyed specific methods of ψleafPC from multiple laboratories, and synthesized experiments testing common assumptions and practices in ψleafPC for diverse species: (i) the need for equilibration of previously transpiring leaves; (ii) leaf storage before measurement; (iii) the equilibration of ψleaf for leaves on bagged branches of a range of dehydration; (iv) the equilibration of ψleaf across the lamina for bagged leaves, and the accuracy of measuring leaves with artificially 'elongated petioles'; (v) the need in ψleaf measurements for bagging leaves and high humidity within the chamber; (vi) the need to avoid liquid water on leaf surfaces; (vii) the use of 'pulse' pressurization versus gradual pressurization; and (viii) variation among experimenters in ψleafPC determination. Based on our findings we provide a best practice protocol to maximise accuracy, and provide recommendations for ongoing species-specific tests of important assumptions in future studies.
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Affiliation(s)
- Celia M. Rodriguez‐Dominguez
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Alicia Forner
- Department of Biogeography and Global Change, International Global Change Laboratory (LINCGlobal), Museo Nacional de Ciencias NaturalesConsejo Superior de Investigaciones CientíficasMadridSpain
- Department of Ecology, Centro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CSIC)University of València and Generalitat ValencianaValenciaSpain
| | - Sebastia Martorell
- Departament de Biologia, Research Group on Plant Biology under Mediterranean ConditionsUniversitat de les Illes BalearsPalma de MallorcaSpain
| | - Brendan Choat
- Plants, Animals and Interactions, Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Rosana Lopez
- Departamento de Sistemas y Recursos NaturalesUniversidad Politécnica de MadridMadridSpain
| | - Jennifer M. R. Peters
- Division of Environmental Science, Oak Ridge National LaboratoryClimate Change Science InstituteOak RidgeTennesseeUSA
| | - Sebastian Pfautsch
- Geography, Tourism and Urban Planning, Urban Studies, School of Social Science and PsychologyWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Madeline R. Carins‐Murphy
- Plant Sciences, Discipline of Biological Sciences, School of Natural SciencesUniversity of TasmaniaHobartAustralia
| | - Scott A. M. McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndianaUSA
| | - Freya Richardson
- Plant Sciences, Discipline of Biological Sciences, School of Natural SciencesUniversity of TasmaniaHobartAustralia
| | - Antonio Diaz‐Espejo
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Virginia Hernandez‐Santana
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Paulo E. Menezes‐Silva
- Laboratory of Integrative Physics and Physiology of Trees in a Fluctuating EnvironmentUniversité Clermont‐Auvergne, INRAE, PIAFClermont‐FerrandFrance
| | - Jose M. Torres‐Ruiz
- Laboratory of Integrative Physics and Physiology of Trees in a Fluctuating EnvironmentUniversité Clermont‐Auvergne, INRAE, PIAFClermont‐FerrandFrance
| | - Timothy A. Batz
- Department of Botany and Plant Pathology, Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndianaUSA
| | - Lawren Sack
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaLos AngelesCaliforniaUSA
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Dainese R, de CFL Lopes B, Tedeschi G, Lamarque LJ, Delzon S, Fourcaud T, Tarantino A. Cross-validation of the high-capacity tensiometer and thermocouple psychrometer for continuous monitoring of xylem water potential in saplings. J Exp Bot 2022; 73:400-412. [PMID: 34505895 PMCID: PMC8730697 DOI: 10.1093/jxb/erab412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
The pressure chamber, the most popular method used to measure xylem water potential, is a discontinuous and destructive technique and is therefore not suitable for automated monitoring. Continuous non-destructive monitoring could until very recently be achieved only by use of the thermocouple psychrometer (TP). Here we present the high-capacity tensiometer (HCT) as an alternative method for continuous non-destructive monitoring. This provided us with a unique chance to cross-validate the two instruments by installing them simultaneously on the same sapling stem. The HCT and the TP showed excellent agreement for xylem water potential less than -0.5 MPa. Response to day/night cycles and watering was remarkably in phase, indicating excellent response time of both instruments despite substantially different working principles. For xylem water potential greater than -0.5 MPa, the discrepancies sometimes observed between the HCT and TP were mainly attributed to the kaolin paste used to establish contact between the xylem and the HCT, which becomes hydraulically poorly conductive in this range of water potential once dried beyond its air-entry value and subsequently re-wetted. Notwithstanding this limitation, which can be overcome by selecting a clay paste with higher air-entry value, the HCT has been shown to represent a valid alternative to the TP.
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Affiliation(s)
- Roberta Dainese
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
- CIRAD, UMR AMAP, Montpellier, France
- AMAP, Univ. Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
| | - Bruna de CFL Lopes
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
| | | | - Laurent J Lamarque
- Univ. Bordeaux, INRAE, UMR BIOGECO, Pessac, France
- Département des Sciences de l’Environnement, UQTR, Trois-Rivières, Québec, Canada
| | | | | | - Alessandro Tarantino
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
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Hayat F, Ahmed MA, Zarebanadkouki M, Javaux M, Cai G, Carminati A. Transpiration Reduction in Maize ( Zea mays L) in Response to Soil Drying. Front Plant Sci 2020; 10:1695. [PMID: 32038676 PMCID: PMC6989490 DOI: 10.3389/fpls.2019.01695] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 12/02/2019] [Indexed: 05/24/2023]
Abstract
The relationship between leaf water potential, soil water potential, and transpiration depends on soil and plant hydraulics and stomata regulation. Recent concepts of stomatal response to soil drying relate stomatal regulation to plant hydraulics, neglecting the loss of soil hydraulic conductance around the roots. Our objective was to measure the effect of soil drying on the soil-plant hydraulic conductance of maize and to test whether stomatal regulation avoids a loss of soil-plant hydraulic conductance in drying soils. We combined a root pressure chamber, in which the soil-root system is pressurized to maintain the leaf xylem at atmospheric pressure, with sap flow sensors to measure transpiration rate. The method provides accurate and high temporal resolution measurements of the relationship between transpiration rate and xylem leaf water potential. A simple soil-plant hydraulic model describing the flow of water across the soil, root, and xylem was used to simulate the relationship between leaf water potential and transpiration rate. The experiments were carried out with 5-week-old maize grown in cylinders of 9 cm diameter and 30 cm height filled with silty soil. The measurements were performed at four different soil water contents (WC). The results showed that the relationship between transpiration and leaf water potential was linear in wet soils, but as the soil dried, the xylem tension increased, and nonlinearities were observed at high transpiration rates. Nonlinearity in the relationship between transpiration and leaf water potential indicated a decrease in the soil-plant hydraulic conductance, which was explained by the loss of hydraulic conductivity around the roots. The hydraulic model well reproduced the observed leaf water potential. Parallel experiments performed with plants not being pressurized showed that plants closed stomata when the soil-plant hydraulic conductance decreased, maintaining the linearity between leaf water potential and transpiration rate. We conclude that stomata closure during soil drying is caused by the loss of soil hydraulic conductivity in a predictable way.
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Affiliation(s)
- Faisal Hayat
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
| | - Mutez Ali Ahmed
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | | | - Mathieu Javaux
- Earth and Life Institute-Environmental Sciences, Universite Catholique de Louvain, Louvain la Neuve, Belgium
- Agrosphere (IBG-3), Forschungszentrum Juelich GmbH, Juelich, Germany
| | - Gaochao Cai
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | - Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
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Hinkelbein J, Jansen S, Iovino I, Kruse S, Meyer M, Cirillo F, Drinhaus H, Hohn A, Klein C, Robertis ED, Beutner D. Thirty Minutes of Hypobaric Hypoxia Provokes Alterations of Immune Response, Haemostasis, and Metabolism Proteins in Human Serum. Int J Mol Sci 2017; 18:E1882. [PMID: 28858246 PMCID: PMC5618531 DOI: 10.3390/ijms18091882] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 08/21/2017] [Accepted: 08/29/2017] [Indexed: 12/20/2022] Open
Abstract
Hypobaric hypoxia (HH) during airline travel induces several (patho-) physiological reactions in the human body. Whereas severe hypoxia is investigated thoroughly, very little is known about effects of moderate or short-term hypoxia, e.g. during airline flights. The aim of the present study was to analyse changes in serum protein expression and activation of signalling cascades in human volunteers staying for 30 min in a simulated altitude equivalent to airline travel. After approval of the local ethics committee, 10 participants were exposed to moderate hypoxia (simulation of 2400 m or 8000 ft for 30 min) in a hypobaric pressure chamber. Before and after hypobaric hypoxia, serum was drawn, centrifuged, and analysed by two-dimensional gel electrophoresis (2-DIGE) and matrix-assisted laser desorption/ionization followed by time-of-flight mass spectrometry (MALDI-TOF). Biological functions of regulated proteins were identified using functional network analysis (GeneMania®, STRING®, and Perseus® software). In participants, oxygen saturation decreased from 98.1 ± 1.3% to 89.2 ± 1.8% during HH. Expression of 14 spots (i.e., 10 proteins: ALB, PGK1, APOE, GAPDH, C1QA, C1QB, CAT, CA1, F2, and CLU) was significantly altered. Bioinformatic analysis revealed an association of the altered proteins with the signalling cascades "regulation of haemostasis" (four proteins), "metabolism" (five proteins), and "leukocyte mediated immune response" (five proteins). Even though hypobaric hypoxia was short and moderate (comparable to an airliner flight), analysis of protein expression in human subjects revealed an association to immune response, protein metabolism, and haemostasis.
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Affiliation(s)
- Jochen Hinkelbein
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, 50937 Cologne, Germany.
| | - Stefanie Jansen
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, 50937 Cologne, Germany.
| | - Ivan Iovino
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Via S. Pansini, 5-80131 Napoli, Italy.
| | - Silvia Kruse
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, 50937 Cologne, Germany.
| | - Moritz Meyer
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, 50937 Cologne, Germany.
| | - Fabrizio Cirillo
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Via S. Pansini, 5-80131 Napoli, Italy.
| | - Hendrik Drinhaus
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, 50937 Cologne, Germany.
| | - Andreas Hohn
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, 50937 Cologne, Germany.
| | - Corinna Klein
- CECAD Lipidomics & Proteomics Facilities, CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.
| | - Edoardo De Robertis
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Via S. Pansini, 5-80131 Napoli, Italy.
| | - Dirk Beutner
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, 50937 Cologne, Germany.
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7
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Meyer MF, Jansen S, Mordkovich O, Hüttenbrink KB, Beutner D. Reliability of Eustachian tube function measurements in a hypobaric and hyperbaric pressure chamber. Clin Otolaryngol 2017; 42:1343-1349. [PMID: 28374944 DOI: 10.1111/coa.12884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2017] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Measurement of the Eustachian tube (ET) function is a challenge. The demand for a precise and meaningful diagnostic tool increases-especially because more and more operative therapies are being offered without objective evidence. The measurement of the ET function by continuous impedance recording in a pressure chamber is an established method, although the reliability of the measurements is still unclear. METHODS Twenty-five participants (50 ears) were exposed to phases of compression and decompression in a hypo- and hyperbaric pressure chamber. The ET function reflecting parameters-ET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF)-were determined under exactly the same preconditions three times in a row. The intraclass correlation coefficient (ICC) and Bland and Altman plot were used to assess test-retest reliability. RESULTS ICCs revealed a high correlation for ETOP and ETOF in phases of decompression (passive equalisation) as well as ETOD and ETOP in phases of compression (active induced equalisation). Very high correlation could be shown for ETOD in decompression and ETOF in compression phases. The Bland and Altman graphs could show that measurements provide results within a 95 % confidence interval in compression and decompression phases. CONCLUSIONS We conclude that measurements in a pressure chamber are a very valuable tool in terms of estimating the ET opening and closing function. Measurements show some variance comparing participants, but provide reliable results within a 95 % confidence interval in retest. This study is the basis for enabling efficacy measurements of ET treatment modalities.
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Affiliation(s)
- M F Meyer
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany
| | - S Jansen
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany
| | - O Mordkovich
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany
| | - K-B Hüttenbrink
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany
| | - D Beutner
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany
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Mandel EM, Casselbrant ML, Richert BC, Teixeira MS, Swarts JD, Doyle WJ. Eustachian Tube Function in 6-Year-Old Children with and without a History of Middle Ear Disease. Otolaryngol Head Neck Surg 2015; 154:502-7. [PMID: 26626132 DOI: 10.1177/0194599815620149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/10/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To test the hypothesis that eustachian tube opening efficiency, measured as the fractional gradient equilibrated (FGE), is lower in 6-year-old children with no middle ear disease but a well-documented history of recurrent acute otitis media, as compared with children with a negative disease history (control). STUDY DESIGN Cross-sectional study. SETTING Tertiary care pediatric hospital. SUBJECTS AND METHODS Bilateral eustachian tube function was evaluated in 44 healthy 6-year-old children (19 boys, 29 white). None had middle ear disease at the time of testing, but 23 had a history of recurrent acute otitis media. Twenty-one had no significant past otitis media. Eustachian tube function was measured with a pressure chamber protocol that established negative middle ear gauge pressures (referenced to the chamber pressure) and recorded that pressure before and after a swallow. FGE was calculated as the change in middle ear gauge pressure with swallowing divided by the preswallow pressure. Between-group comparisons of the preswallow pressures and FGEs were made with a 2-tailed Student's t test. RESULTS FGE was independent of the preswallow middle ear gauge pressure. For the 39 and 44 evaluable ears in the control and recurrent acute otitis media groups, the mean preswallow pressures were -194 daPa (95% confidence interval [95% CI] = -211 to -177) versus -203 (95% CI = -216 to -190; P > .40), and FGEs were 0.32 (95% CI = 0.21-0.43) vs 0.16 (95% CI = 0.08-0.24; P = .016), respectively. CONCLUSION In children with past recurrent acute otitis media, residual eustachian tube opening inefficiency is maintained after they have "outgrown" their middle ear disease.
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Affiliation(s)
- Ellen M Mandel
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Division of Pediatric Otolaryngology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
| | - Margaretha L Casselbrant
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Beverly C Richert
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Division of Pediatric Otolaryngology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
| | - Miriam S Teixeira
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - J Douglas Swarts
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - William J Doyle
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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9
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Ding Y, Zhang Y, Zheng QS, Tyree MT. Pressure-volume curves: revisiting the impact of negative turgor during cell collapse by literature review and simulations of cell micromechanics. New Phytol 2014; 203:378-387. [PMID: 24787280 DOI: 10.1111/nph.12829] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/30/2014] [Indexed: 05/15/2023]
Abstract
The Scholander-Hammel pressure chamber has been used in thousands of papers to measure osmotic pressure, πc , turgor pressure, Pt , and bulk modulus of elasticity, ε, of leaf cells by pressure-volume (PV) curve analysis. PV analysis has been questioned in the past. In this paper we use micromechanical analysis of leaf cells to examine the impact on PV curve analysis of negative turgor in living cells (Pt ). Models predict negative Pt (-0.1 to -1.8 MPa) depending on leaf cell size and shape in agreement with experimental values reported by J. J. Oertli. Modeled PV curves have linear regions even when Pt is quite negative, contrary to the arguments of M.T. Tyree. Negative Pt is totally missed by PV curve analysis and results in large errors in derived πc and Pt but smaller errors in ε. A survey of leaf cell sizes vs habitat (arid, temperate, and rainforest), suggests that the majority of published PV curves result in errors of 0.1-1.8 MPa in derived πc and Pt , whereby the error increases with decreasing cell size. We propose that small cell size in leaves is an ecological adaptation that permits plants to endure negative values of water potential with relatively little water loss.
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Affiliation(s)
- Yiting Ding
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yanxiang Zhang
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, T6G 2G8, Canada
| | - Quan-Shui Zheng
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Melvin T Tyree
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
- College of Forestry, Northwest A&F University, Yangling, 712100, China
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10
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Meyer CJ, Peterson CA, Steudle E. Permeability of Iris germanica's multiseriate exodermis to water, NaCl, and ethanol. J Exp Bot 2011; 62:1911-1926. [PMID: 21131546 PMCID: PMC3060676 DOI: 10.1093/jxb/erq380] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 10/12/2010] [Accepted: 11/02/2010] [Indexed: 05/28/2023]
Abstract
The exodermis of Iris germanica roots is multiseriate. Its outermost layer matures first with typical Casparian bands and suberin lamellae. But as subsequent layers mature, the Casparian band extends into the tangential and anticlinal walls of their cells. Compared with roots in which the endodermis represents the major transport barrier, the multiseriate exodermis (MEX) was expected to reduce markedly radial water and solute transport. To test this idea, precocious maturation of the exodermis was induced with a humid air gap inside a hydroponic chamber. Hydraulic conductivity (Lp(pc)) was measured on completely submerged roots (with an immature exodermis) and on air-gap-exposed root regions (with two mature exodermal layers) using a pressure chamber. Compared with regions of roots with no mature exodermal layers, the mature MEX reduced Lp(pc) from 8.5×10(-8) to 3.9×10(-8) m s(-1) MPa(-1). Puncturing the MEX increased Lp(pc) to 19×10(-8) m s(-1) MPa(-1), indicating that this layer constituted a substantial hydraulic resistance within the root (75% of the total). Alternatively, a root pressure probe was used to produce pressure transients from which hydraulic conductivity was determined, but this device measured mainly flow through the endodermis in these wide-diameter roots. The permeability of roots to NaCl and ethanol was also reduced in the presence of two mature MEX layers. The data are discussed in terms of the validity of current root models and in terms of a potential role for I. germanica MEX during conditions of drought and salt stress.
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Affiliation(s)
- Chris J Meyer
- Department of Biology, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1
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