Search

We have studied cardiac and respiratory functions of aquaporin- 1-deficient mice by the Pressure-Volume-loop technique and by blood gas analysis. In addition, the morphological properties of the animals’ hearts were analysed. In anesthesia under maximal dobutamine stimulation, the mice exhibit a moderately elevated heart rate of < 600 min-1 and an O2 consumption of ~0.6 ml/min/g, which is about twice the basal rate. In this state, which is similar to the resting state of the conscious animal, all cardiac functions including stroke volume and cardiac output exhibited resting values and were identical between deficient and wildtype animals. Likewise, pulmonary and peripheral exchange of O2 and CO2 were normal. In contrast, several morphological parameters of the heart tissue of deficient mice were altered: 1) left ventricular wall thickness was reduced by 12%, 2) left ventricular mass, normalized to tibia length, was reduced by 10-20%, 3) cardiac muscle fiber cross sectional area was decreased by 17%, and 4) capillary density was diminished by 10%. As the P-V-loop technique yielded normal end-diastolic and end-systolic left ventricular volumes, the deficient hearts are characterized by thin ventricular walls in combination with normal intraventricular volumes. The aquaporin-1-deficient heart thus seems to be at a disadvantage compared to the wildtype heart by a reduced left-ventricular wall thickness and an increased diffusion distance between blood capillaries and muscle mitochondria. While under the present quasi-resting conditions these morphological alterations have no consequences for cardiac function, we expect that the deficient hearts will show a reduced maximal cardiac output.

Sensitivity to spatial and temporal patterns is a fundamental aspect of vision. Herein, we investigated this sensitivity in adult zebrafish for a wide range of spatial (0.014 to 0.511 cycles/degree [c/d]) and temporal frequencies (0.025 to 6 cycles/second) to better understand their visual system. Measurements were performed at photopic (1.8 log cd m-2) and scotopic (-4.5 log cd m-2) light levels to assess the optokinetic response. The resulting spatiotemporal contrast sensitivity functions revealed that the optokinetic response of zebrafish is tuned to spatial frequency and speed but not to temporal frequencies. Thereby, optimal test parameters for contrast sensitivity measurements were identified. At photopic light levels, a spatial frequency of 0.116 ± 0.01 c/d (mean ± SD) and a grating speed of 8.42 ± 2.15 degrees/second (d/s) was ideal; at scotopic light levels, these values were 0.110 ± 0.02 c/d and 5.45 ± 1.31 d/s, respectively. This study allows to better characterize zebrafish mutants with altered vision and to distinguish between defects of rod and cone photoreceptors as measurements were performed under different light conditions.

We review briefly how the thinking about the permeation of gases, especially CO2, across cell and artificial lipid membranes has evolved during the last hundred years. We then describe how the recent finding of a drastic effect of cholesterol on CO2 permeability of both biological and artificial membranes fundamentally alters the long-standing idea that CO2 – as well as other gases – permeates all membranes with great ease. This requires revision of the widely accepted paradigm that membranes never offer a serious diffusion resistance to CO2 or other gases. Earlier observations of CO2-impermeable membranes can now be explained by the high cholesterol content of some membranes. Thus, cholesterol is a membrane component that nature can use to adapt membrane CO2 permeability to the functional needs of the cell. Since cholesterol serves many other cellular functions, it cannot be reduced indefinitely. We show, however, that cells that possess a high metabolic rate and/or a high rate of O2 and CO2 exchange, do require very high CO2 permeabilities that may not be achievable merely by reduction of membrane cholesterol. The article then discusses the alternative possibility of raising the CO2 permeability of a membrane by incorporating protein CO2 channels. The highly controversial issue of gas and CO2 channels is systematically and critically reviewed. It is concluded that a majority of the results considered to be reliable, is in favour of the concept of existence and functional relevance of protein gas channels. The effect of intracellular carbonic anhydrase, which has recently been proposed as an alternative mechanism to a membrane CO2 channel, is analysed quantitatively and the idea considered untenable. After a brief review of the knowledge on permeation of O2 and NO through membranes, we present a summary of the 18O method used to measure the CO2 permeability of membranes and discuss quantitatively critical questions that may be addressed to this method.

Most legume species establish a symbiotic association with soil bacteria. The plant accommodates the differentiated rhizobia in specialized organs, the root nodules. In this environment, the microsymbiont reduces atmospheric nitrogen (N) making it available for plant metabolism. Symbiotic N fixation is driven by the respiration of the host photosynthates and thus constitutes an additional carbon sink for the plant. Molecular phenotypes of symbiotic and non-symbiotic M. truncatula are identified. The implication of nodule symbiosis on plant abiotic stress response mechanisms is not well understood. In this study, we exposed nodulated and non-symbiotic N fertilized plants to salt and drought conditions. We assessed the stress effects with proteomic and metabolomic methods and found a nutritionally regulated phenotypic plasticity pivotal for a differential stress adjustment strategy.

The ProMEX database is one of the main collection of annotated tryptic peptides in plant proteomics. The main objective of the ProMEX Database is to provide experimental MS/MS-based information for cell type-specific or subcellular proteomes in Arabidopsis thaliana, Medicago truncatula, Chlamydomonas reinhardtii, Lotus japonicus, Lotus corniculatus, Phaseolus vulgaris, Lycopersicon esculentum, Solanum tuberosum, Nicotiana tabacum, Glycine max, Zea mays, Bradyrhizobium japonicum and Sinorhizobium meliloti. Direct links at the protein level to the most relevant databases are present in ProMEX. Furthermore, the spectral sequence information are linked to their respective pathways and can be viewed in pathway maps.

Diaphragm paralysis and eventration are rare conditions in adults. Symptomatic patients may benefit from surgical plication of the elevated hemidiaphragm. The objective of this study was to compare short-term outcomes and length of stay following robotic-assisted vs. open diaphragm plication. A multicenter retrospective study was conducted that identified patients undergoing unilateral hemidiaphragm plication from 5/2008 to 12/2020. The first RATS plication was performed in 11/2018. Electronic medical records were reviewed, and outcomes were compared between RATS and open approach. One hundred patients underwent diaphragm plication, including thirty-nine (39.0%) RATS and sixty-one (61.0%) open cases. Patients undergoing RATS diaphragm plication were older (64 years vs. 55 years, p = 0.01) and carried a higher burden of comorbidities (Charlson Comorbidity Index: 2.0 vs. 1.0, p = 0.02). The RATS group had longer median operative times (146 min vs. 99 min, p < 0.01), but shorter median hospital length of stays (3.0 days vs. 6.0 days, p < 0.01). There was a non-significant trend toward a decreased rate of 30-day postoperative complications (20.5% RATS vs. 32.8% open, p = 0.18) and 30-day unplanned readmissions (7.7% RATS vs. 9.8% open, p > 0.99). RATS is a technically feasible and safe option for performing diaphragm plications. This approach increases the surgical candidacy of older patients with a higher burden of comorbid disease without increasing complication rates, while reducing length of hospital stay., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Rationale: Rigid bronchoscopy is increasingly used by pulmonologists for the management of central airway disorders. However, an assessment tool to evaluate the competency of operators in the performance of this technique has not been developed. We created the Rigid Bronchoscopy Tool for Assessment of Skills and Competence (RIGID-TASC) to serve as an objective, competency-oriented assessment tool of basic rigid bronchoscopic skills, including rigid bronchoscopic intubation and central airway navigation., Objectives: To assess whether RIGID-TASC scores accurately distinguish the basic rigid bronchoscopy skills of novice, intermediate, and expert operators, and to determine whether RIGID-TASC has adequate interrater reliability when used by different independent testers., Methods: At two academic medical centers in the United States, 30 physician volunteers were selected in three categories: 10 novices at rigid bronchoscopy (performed at least 50 flexible, but no rigid, bronchoscopies), 10 operators with intermediate experience (performed 5-20 rigid bronchoscopies), and 10 experts (performed ≥100 rigid bronchoscopies). Participants included pulmonary and critical care fellows, interventional pulmonology fellows, and faculty interventional pulmonologists. Each subject then performed rigid bronchoscopic intubation and navigation on a manikin, while being scored independently by two testers, using RIGID-TASC., Measurements and Main Results: Mean scores for three categories (novice, intermediate, and expert) were 58.10 (±4.6 [SE]), 78.15 (±3.8), and 94.40 (±1.1), respectively. There was significant difference between novice and intermediate (20.05, 95% confidence interval [CI] = 7.77-32.33, P = 0.001), and intermediate and expert (16.25, 95% CI = 3.97-28.53, P = 0.008) operators. The interrater reliability (intraclass correlation coefficient) between the two testers was high (r = 0.95, 95% CI = 0.90-0.98)., Conclusions: RIGID-TASC showed evidence of construct validity and interrater reliability in this setting and group of subjects. It can be used to reliably and objectively score and classify operators from novice to expert in basic rigid bronchoscopic intubation and navigation.