Morphoanatomical Symptomatology and Osmotic Behavior of Grape Berry Shrivel

Berry shrivel, a physiological disorder, adversely affects ripening of grape (Vitis vinifera L.) berries; however, its causes are unknown. We adopted a holistic approach to elucidate symptomatology, morphoanatomy, and osmotic behavior of grape berry shrivel. Berries from healthy and afflicted vines were analyzed compositionally and with various techniques of microscopy. Healthy berries developed all physical and compositional attributes desirable for wine-making. Conversely, berry shrivel berries were grossly metamorphosed manifested as shriveling of the pericarp, which paralleled with loss of membrane competence in the mesocarp cells causing its collapse and a loss of brush. The most intriguing observation was the presence of non-druse crystals. These berries had high osmotic potential (ψS) as a result of low accumulations of sugar and potassium. Nonetheless, the seed morphology, structure, and viability were similar to healthy seeds. Berry shrivel grotesquely modified grape berries both compositionally and structurally, which was paralleled by their inability to accumulate sugars followed by cell death in the mesocarp. Although the mechanisms of berry shrivel remain uncertain, our study provides valuable background information for generating suitable guidelines to minimize the incidences of berry shrivel and also to design future studies toward unraveling the mechanistic basis of berry shrivel.

Regional differences in osmotic behavior in brain during acute hyponatremia: an in vivo MRI-study of brain and skeletal muscle in pigs

Brain edema is suggested to be the principal mechanism underlying the symptoms in acute hyponatremia. Identification of the mechanisms responsible for global and regional cerebral water homeostasis during hyponatremia is, therefore, of utmost importance. To examine the osmotic behavior of different brain regions and muscles, in vivo-determined water content (WC) was related to plasma sodium concentration ([Na+]) and brain/muscle electrolyte content. Acute hyponatremia was induced with desmopressin acetate and infusion of a 2.5% glucose solution in anesthetized pigs. WC in different brain regions and skeletal muscle was estimated in vivo from T1 maps determined by magnetic resonance imaging (MRI). WC, expressed in gram water per 100 g dry weight, increased significantly in slices of the whole brain [342(SD = 14) to 363(SD = 21)] (6%), thalamus [277(SD = 13) to 311(SD = 24)] (12%) and white matter [219(SD = 7) to 225(SD = 5)] (3%). However, the WC increase in the whole brain and white mater WC was less than expected from perfect osmotic behavior, whereas in the thalamus, the water increase was as expected. Brain sodium content was significantly reduced. Muscle WC changed passively with plasma [Na+]. WC determined with deuterium dilution and tissue lyophilzation correlated well with MRI-determined WC. In conclusion, acute hyponatremia induces brain and muscle edema. In the brain as a whole and in the thalamus, regulatory volume decrease (RVD) is unlikely to occur. However, RVD may, in part, explain the observed lower WC in white matter. This may play a potential role in osmotic demyelination.

Quantitative Measurements of Cryobiological Characteristics of Mouse Dendritic Cells and Its Evaluation Using Commercialized Coulter Counter

Quantitative measurements of cell osmotic behavior and membrane transport properties is critical for the development of cell-type-specific, optimal cryopreservation conditions. A microfluidic perfusion system has been developed here to measure the kinetic changes of cell volume under various extracellular conditions, in order to determine cell osmotic behavior and membrane transport properties. The system is fabricated using soft lithographic techniques and is composed of inlets, outlets, micchannels and a perfusion chamber for trapping cells. In this study Dendritic cells (DCs) are using as a model to validate our microfluidic system with a commercialized Beckham Coulter Counter (Multisizer 3). DCs are antigen presenting cells that have been increasingly used in immunotherapy for the treatment of various diseases. Cryopreservation and banking of DCs is critical to facilitate flexible and effective immunotherapy treatment. Using mouse DCs (MDC), membrane transport properties were first investigated using our microfluidic perfusion system. Cells in the microfluidic system were perfused with 3x phosphate buffer solution. The kinetics of cell volume changes under the specific extracellular conditions were monitored by a digital camera and analyzed using a biophysical model to determine water and cryoprotectant transport properties of the cell membrane. DCs were later tested using Beckman Coulter Counter, where the kinetic osmotic behaviors of cells were quantified through the correlation between electric pulses and their corresponding cell sizes. It was shown from this study that the cryobiological characteristics of DCs determined using microfluidic perfusion system and Coulter Counter agreed well.