Background: The Sencell sensor (Lifecare AS, Bergen, Norway) uses glucose induced changes in an osmotic pressure chamber for continuous measurement of glucose concentrations in the subcutaneous ...tissue. A close to linear correlation between the raw sensor signal and the glucose concentration and a very long duration of use (of up to 6-12 months or longer) are theoretically to be expected. The final device is planned to have the size of a grain of rice and to be implanted employing wireless energy and data transfer.
Method: For a first clinical proof of concept study in humans, a wired version of the core sensing technology was embedded into a 4 mm needle and inserted into the abdominal subcutaneous tissue of healthy volunteers. The study was conducted to collect first human proof-of-concept performance data for algorithm development during meal experiments and for further device optimization. The raw data was analyzed after one-point calibration and minor trend correction in comparison to the Statstrip blood glucose meter and the Freestyle Libre 2 glucose sensor.
Results: Seven participants (5 female, 2 male, age: 49±11 years) delivered a total of 105 direct comparator data-points (vs. Statstrip blood glucose meter) during repeated meal experiments with observation periods between 2 h and up to 72 days. The osmotic-pressure sensor followed glucose changes similar to the FreeStyle Libre device and reached an MARD of 9.8% in comparison to StatStrip (87 % and 13 % of the datapoints were lying in zones A and B of the consensus error grid, respectively).
Conclusions: In this first human proof-of-concept study, the osmotic-pressure based continuous glucose sensor was shown to track s.c. glucose concentrations in a comparable manner as the Libre 2 needle sensor. The clinical performance characteristics of the first wired prototypes provide an encouraging perspective for the upcoming next development steps.
Disclosure
A. Pfützner: Consultant; Novo Nordisk A/S, Research Support; LifeScan Diabetes Institute, Speaker's Bureau; AstraZeneca, Stock/Shareholder; Lifecare A/S, Diakard. M. Hanna: None. N. Thomé: None. H. Jensch: None.
Funding
Lifecare AS (LIFC-SEN-001)
•Osmotic pressure affected the ratio of erythritol to mannitol production.•A novel osmotic pressure control strategy improved erythritol production.•Substrate-feeding kept the osmotic pressure at a ...relatively constant level.•Erythritol production reached 194.3g/L.•High osmotic pressure and low pH protect the culture against contamination.
The effect of osmotic pressure on erythritol and mannitol production by an osmophilic yeast strain of Yarrowia lipolytica CICC 1675 using glycerol as the sole carbon source was investigated. Appropriately high osmotic pressure was found to enhance erythritol production and inhibit mannitol formation. A novel two-stage osmotic pressure control fed-batch strategy based on the kinetic analysis was developed for higher erythritol yield and productivity. During the first 96h, the osmotic pressure was maintained at 4.25osmol/kg by feeding glycerol to reduce the inhibition of cell growth. After 132h, the osmotic pressure was controlled at 4.94osmol/kg to maintain a high dpery/dt. Maximum erythritol yield of 194.3g/L was obtained with 0.95g/L/h productivity, which were 25.7% and 2.2%, respectively, improvement over the best results in one-stage fed-batch fermentation. This is the first report that a novel osmotic pressure control fed-batch strategy significantly enhanced erythritol production.
In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade initiated by cytosolic calcium concentration elevation. Members of ...the OSCA family in Arabidopsis thaliana, identified as the hyperosmolality-gated calcium-permeable channels, have been suggested to play a key role during the initial phase of hyperosmotic stress response. Here, we report the atomic structure of Arabidopsis OSCA1.2 determined by single-particle cryo-electron microscopy. It contains 11 transmembrane helices and forms a homodimer. It is in an inactivated state, and the pore-lining residues are clearly identified. Its cytosolic domain contains a RNA recognition motif and two unique long helices. The linker between these two helices forms an anchor in the lipid bilayer and may be essential to osmosensing. The structure of AtOSCA1.2 serves as a platform for the study of the mechanism underlying osmotic stress responses and mechanosensing.
There is growing evidence that microRNAs (miRNAs) are implicated in cellular adaptation to osmotic stress, but the underlying osmosignaling pathways are still not completely understood. In this ...study, we found that a passenger strand miRNA, miR-23a-5p, was significantly downregulated in response to high NaCl treatment in mouse inner medullary collecting duct cells (mIMCD3) through an miRNA profiling assay. The decrease of miR-23a-5p is hypertonicity-dependent and osmotolerant cell type-specific. Knockdown of miR-23a-5p increased cellular survival and proliferation in mIMCD3. In contrast, miR-23a-5p overexpression repressed cell viability and proliferation under hypertonic stress. RNA deep-sequencing revealed that a heat shock protein 70 (HSP70) isoform, HSP70 member 1B (HSPA1B), was significantly increased under hypertonic treatment. Based on the prediction analysis by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and TargetScan, and a further validation via a dual-luciferase assay, HSPA1B was identified as a potential target of miR-23a-5p. Overexpressed miR-23a-5p suppressed HSPA1B, whereas downregulated miR-23a-5p promoted HSPA1B expression in mIMCD3. In addition, an in vivo study demonstrated that there is a reverse correlation between the levels of miR-23a-5p and HSPA1B in mouse renal inner medulla (papilla) that is exposed to extremely high osmolality. In summary, this study elucidates that passenger strand miR-23a-5p is a novel tonicity-responsive miRNA. The downregulation of miR-23a-5p facilitates cellular adaptation to hypertonic stress in mammalian renal cells through modulating HSPA1B.
Salted egg is one of the egg types that has a lot of devotees because it tastes a little salty and savory. Salted eggs are usually homemade in various regions. The easy process of making them has ...attracted many people to do so. This study developed a PLC-based on automatic system for a salted egg maker using the osmotic pressure method to accelerate the opening of the semi-permeable membrane on duck eggshells so that the salting mixture seeps into the eggs more quickly. It was carried out in an osmotic pool containing water and acetic acid at a concentration of 5%. The data collection process in designing the salted egg maker consisted of evaluating the performance of photoelectric sensors, proximity sensors, temperature controller, thermostat set point, baking time, and salted egg durability test. The results of the tests indicated that the time needed to make salted eggs from raw eggs to cooked eggs only took 36 minutes using the machine designed. Additionally, the presented salted egg maker reveals the short making time, and long salted egg durability. altogether revealing full potential to be easily used for practical applications.
Abstract
Context
Copeptin is the C-terminal fragment of the arginine vasopressin (AVP) prohormone whose measurement is more robust than that of AVP. Similar release and clearance characteristics have ...been suggested promoting copeptin as a surrogate marker.
Objective
To characterize the physiology of osmotically regulated copeptin release and its half-life in direct comparison with plasma AVP.
Design
Ninety-one healthy volunteers underwent a standardized three-phase test protocol including (1) osmotic stimulation into the hypertonic range by hypertonic-saline infusion followed by osmotic suppression via (2) oral water load and (3) subsequent glucose infusion. Plasma copeptin, AVP, serum sodium, and osmolality levels were measured in regular intervals.
Results
In phase 1, an increase in median osmotic pressure 289 (286; 291) to 311 (309; 314) mOsm/kg H2O caused similar release kinetics of plasma copeptin 4 (3.1; 6) to 29.3 (18.6; 48.2) pmol/L and AVP 1 (0.7; 1.6) to 10.3 (6.8; 18.8) pg/mL. Subsequent osmotic suppression to 298 (295; 301) mOsm/kg at the end of phase 3 revealed markedly different decay kinetics between both peptides—an estimated initial half-life of copeptin being approximately 2 times longer than that of AVP (26 vs 12 minutes).
Conclusion
Copeptin is released in equimolar amounts with AVP in response to osmotic stimulation, suggesting its high potential as an AVP surrogate for differentiation of osmotic disorders. Furthermore, we here describe the decay kinetics of copeptin in response to osmotic depression enabling to identify a half-life for copeptin in direct comparison with AVP.
We constructed the physiological area of copeptin release in normo- and hyperosmolar state and analyzed decay kinetics of copeptin, giving information about its half-life in direct comparison with AVP.
Recently, four-dimensional (4D) printing is emerging as the next-generation biofabrication technology. However, current 4D bioprinting lacks biocompatibility or multi-component printability. In ...addition, suitable implantable targets capable of applying 4D bioprinted products have not yet been established, except theoretical and in vitro study. Herein, we describe a cell-friendly and biocompatible 4D bioprinting system including more than two cell types based on digital light processing (DLP) and photocurable silk fibroin (Sil-MA) hydrogel. The shape changes of 3D printed bilayered Sil-MA hydrogels were controlled by modulating their interior or exterior properties in physiological conditions. We used finite element analysis (FEA) simulations to explore the possible changes in the complex structure. Finally, we made trachea mimetic tissue with two cell types using this 4D bioprinting system and implanted it into a damaged trachea of rabbit for 8 weeks. The implants were integrated with the host trachea naturally, and both epithelium and cartilage were formed at the predicted sites. These findings demonstrate that 4D bioprinting system could make tissue mimetic scaffold biologically and suggest the potential value of the 4D bioprinting system for tissue engineering and the clinical application.
Regulation of Plant Responses to Salt Stress Zhao, Shuangshuang; Zhang, Qikun; Liu, Mingyue ...
International journal of molecular sciences,
04/2021, Volume:
22, Issue:
9
Journal Article
Peer reviewed
Open access
Salt stress is a major environmental stress that affects plant growth and development. Plants are sessile and thus have to develop suitable mechanisms to adapt to high-salt environments. Salt stress ...increases the intracellular osmotic pressure and can cause the accumulation of sodium to toxic levels. Thus, in response to salt stress signals, plants adapt via various mechanisms, including regulating ion homeostasis, activating the osmotic stress pathway, mediating plant hormone signaling, and regulating cytoskeleton dynamics and the cell wall composition. Unraveling the mechanisms underlying these physiological and biochemical responses to salt stress could provide valuable strategies to improve agricultural crop yields. In this review, we summarize recent developments in our understanding of the regulation of plant salt stress.
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