Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots

It is not known to what degree aquaporin-facilitated water uptake differs between root developmental regions and types of root. The aim of this study was to measure aquaporin-dependent water flow in the main types of root and root developmental regions of 14- to 17-d-old barley plants and to identify candidate aquaporins which mediate this flow. Water flow at root level was related to flow at cell and plant level. Plants were grown hydroponically. Hydraulic conductivity of cells and roots was determined with a pressure probe and through exudation, respectively, and whole-plant water flow (transpiration) determined gravimetrically in response to the commonly used aquaporin inhibitor HgCl2. Expression of aquaporins was analysed by real-time PCR and in situ hybridization. Hydraulic conductivity of cortical cells in seminal roots was largest in lateral roots; it was smallest in the fully mature zone and intermediate in the not fully mature ‘transition’ zone along the main root axis. Adventitious roots displayed an even higher (3- to 4-fold) cortical cell hydraulic conductivity in the transition zone. This coincided with 3- to 4-fold higher expression of three aquaporins (HvPIP2;2, HvPIP2;5, HvTIP1:1). These were expressed (also) in cortical tissue. The largest inhibition of water flow (83–95%) in response to HgCl2 was observed in cortical cells. Water flow through roots and plants was reduced less (40–74%). It is concluded that aquaporins contribute substantially to root water uptake in 14- to 17-d-old barley plants. Most water uptake occurs through lateral roots. HvPIP2;5, HvPIP2;2, and HvTIP1;1 are prime candidates to mediate water flow in cortical tissue

Developmental pattern of aquaporin expression in barley (Hordeum vulgare L.) leaves

Aquaporins are multifunctional membrane channels which belong to the family of major intrinsic proteins (MIPs) and are best known for their ability to facilitate the movement of water. In the present study, earlier results from microarray experiments were followed up. These experiments had suggested that, in barley (Hordeum vulgare L.), aquaporin family members are expressed in distinct patterns during leaf development. Real-time PCR and in situ hybridization were used to analyse the level and tissue-distribution of expression of candidate aquaporins, focusing on plasma membrane and tonoplast intrinsic proteins (PIPs, TIPs). Water channel function of seven aquaporins, whose transcripts were the most abundant and the most variable, was tested through expression in yeast and, in part, through expression in oocytes. All PIP1 and PIP2 subfamily members changed in expression during leaf development, with expression being much higher or lower in growing compared with mature tissue. The same applied to those TIPs which were expressed at detectable levels. Specific roles during leaf development are proposed for particular aquaporins

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Metatarsalgia

The causes of metatarsalgia are classified as primary, secondary, and iatrogenic. Anatomical and biomechanical considerations separate "static" from "propulsive" forms of metatarsalgia. The physical examination should be combined with an assessment of weight-bearing radiographs and, if needed, of ultrasound or magnetic resonance imaging scans. The first-line treatment is conservative (stretching exercises, footwear modification, insoles, and lesion debridement). Soft-tissue surgical procedures (gastrocnemius muscle recession, tendon transfer, and plantar plate repair) should also be considered. Among the various types of metatarsal osteotomy, the Weil procedure is reliable. Percutaneous methods are being developed but require evaluation. A treatment algorithm can be developed based on whether the hallux is normal or abnormal. Metatarsalgia due to inflammatory disease requires a specific treatment strategy

Osteolytic cysts with total ankle replacement: Frequency and causes?

In this issue, the article 'Etiopathogeneis of osteolytic cysts associated with total ankle arthroplasty, a histological study' by R. van Wijngaarden et al. reported histologic analysis of 32 cyst samples from 22 reoperated TAAs (14 CCI®, 6 Buechel-Pappas®, 1 Salto®, 1 AES® TARs). Having found PE particles in all samples, and metal particles in 16 cysts, the authors concluded that polyethylene particles are not the primary cause of osteolytic cyst. These conclusions are in agreement with Koivu's study and with our histological study, not cited in the article referred to here

Response of the editorial team to M. Goldzak's letter

Response of the editorial team to M. Goldzak's lette

Cinétique d'apparition et de réversion de la mutation T215Y/F dans le compartiment cellulaire sanguin chez les patients infectés par le VIHétude descriptive sur 108 patients traités (étude descriptive sur 108 patients traités)

PARIS6-Bibl. St Antoine CHU (751122104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Anterior cruciate ligament revision: analysis and results from a series of 74 cases

Résumé Cette étude rétrospective d'une série continue de 100 patients opérés pour une reprise de ligamentoplastie du ligament croisé antérieur (LCA) entre 1996 et 2004 avait pour but d'apprécier le résultat fonctionnel et de déterminer d'éventuels facteurs pronostiques. La série comportait 74 ligamentoplasties du LCA avec un recul supérieur à 1 an. L'évaluation fonctionnelle a utilisé le score IKDC. La laxité a été mesurée par l'arthromètre KT-1000 et par des radiographies dynamiques. La reconstruction ligamentaire a été réalisée 78 mois en moyenne après l'intervention initiale et dans 93 % des cas sous arthroscopie. Une autogreffe a été utilisée dans tous les cas, avec 57 % de tendons rotuliens, 20 % de tendons quadricipitaux, 18 % de tendons ischio-jambiers, 4 % de tendons rotuliens associés à un tendon quadricipital et 1 % de fascia lata. Le recul moyen est de 21,2 mois. Le score IKDC subjectif moyen était de 71,7 sur 100 et 78 % des genoux étaient considérés comme normaux ou presque normaux à l'examen. Les mesures arthrométriques ont montré un gain moyen en laxité différentielle de 5 mm ± 3 pour le test maxi-manuel. Les radiographies dynamiques ont montré un gain moyen en laxité différentielle de 3 mm ± 4 sur le compartiment médial et de 2 mm ± 4,5 sur le compartiment latéral. L'existence de lésions méniscales (24 cas) a favorisé la dégradation arthrosique et l'existence de lésions cartilagineuses (33 cas) ont altéré le résultat fonctionnel. Les reprises de ligamentoplastie du LCA n'ont pas donné un résultat fonctionnel aussi bon que lors d'une plastie de première intention. L'utilisation initiale d'un ligament synthétique, l'existence de lésions méniscales et cartilagineuses ont été un facteur péjoratif. Purpose of the study This was a retrospective series of patients who underwent revision ligamentoplasty of the anterior cruciate ligament (ACL). We wanted to assess the functional outcome after this type of surgery and search for potential prognostic factors. Material and methods The series included 74 patients, mean age 34 years (range 21-59 years). The initial ligamentoplasty was performed with a synthetic ligament (n = 16), an autograft (n = 57) or an allograft (n = 1). Differential laxity (KT-1000 maximal manual) was 7 ± 2.5 mm. Anterior drawer was measured on the stress x-rays in 20° flexion: medial 8 ± 4.7 mm, lateral 8.3 ± 4.9 mm. Mean time to revision surgery was 78 months. Reconstruction was performed arthroscopically in 69 knees. The implant used for the revision reconstruction was an autograft: patellar tendon (n = 42), quadriceps tendon (n = 15), hamstring tendon (n = 13), patellar tendon and quadriceps tendon (MacInJones) (n = 3), fascia lata (n = 1). A meniscal tear was noted in 24 knees and a cartilage lesion in 35. Results Outcome was assessed at mean 21.2 months follow-up. The mean IKDC function score was 71.7 (range 21.8-100). 78% of patients considered their knee normal or nearly normal and 88% presented a positive Lachmann. Mean differential laxity measured with KT-1000 (maximal manual) was 2 ± 1.7 mm. Stress x-rays revealed a mean differential laxity measured at 3.7 ± 2.3 mm medially and 6.3 ± 4.3 mm laterally. The presence of a meniscal lesion favored osteoarthritic degradation. Presence of chondral lesions altered the functional outcome significantly and limited resumption of sports activities. An initial repair using a synthetic ligament affected the functional outcome after revision surgery and favored or aggravated chondral lesions. Discussion The clinical results we have obtained with revision ACL ligamentoplasty are comparable to pervious series reported in the literature. The functional outcome is not as good as after first-intention repair, especially if the initial plasty was done with a synthetic ligament and the knee presented meniscal or cartilage damage