Studies on bound water restrained by poly(2-methacryloyloxyethyl phosphorylcholine): Comparison with polysaccharide–water systems

The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC–water systems with a water content (W_c = mass of water/mass of dry sample, g g^?1) in the range 0–2.0 was measured in the temperature range ?150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a W_c in the range 0.5–0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ～0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC.     

Intracellular aquaporins: clues for intracellular water transport?

Aquaporins (AQPs) are usually present at the plasma membrane to regulate influx and outflow of water and small molecules. They are important for the regulation of water homeostasis for the cells and organisms. AQPs are also present inside the cell, at the membranes of intracellular organelles. The roles of such AQPs have not yet been established. They will be clues to clarify the mechanisms of water and small solutes movements inside the cell. Recently, a new AQP subfamily has been identified with highly deviated asparagine-proline-alanine boxes, signature sequences for AQP. With limited homology less than 20%, this subfamily will be a superfamily of AQPs. Accordingly, it was tentatively named "superaquaporin subfamily," which is so far only present in multicellular organisms including plants, insects, nematodes, and vertebrates. Some superaquaporins are functionally water channels and localized intracellularly. AQP11, one of the two superaquaporins in mammals, has been shown to be important for the development of the proximal tubule as its disruption produced neonatally fatal polycystic kidneys in mice. Hence, recent identification of intracellular AQPs will open new areas of research on cell biology and expand the scope of AQPs.     

Dielectric relaxation of a protein–water system in atherosclerotic artery wall

Measurements of the dielectric properties of healthy and atherosclerotic human artery tissues were made in the frequency range of 100 Hz–100 kHz and temperatures from 22 to 260°C. The temperature dependencies of the dielectric parameters for healthy tissues reveal distinctively the temperature ranges corresponding to the release of water up to 200°C and the decomposition processes of elastin and collagen, above this temperature. The influence of atherosclerosis on the dielectric properties of artery tissues is significant in the whole temperature range. The relative permittivity for atherosclerotic tissues at the same temperature is much lower than for the healthy tissues. This suggests, that the polarization in atherosclerotic tissues due to protons hopping between a smaller number of sites than in healthy tissues, as a results of the thermal degradation of collagen–water. The data obtained above 200°C indicate that the atherosclerosis induces the higher physico-chemical changes in the collagen when compared to elastin.     

Asbestos fibres in drinking water: are they carcinogenic or not?

The paper discusses the possibility of a carcinogenic effect of consuming drinking water contaminated by asbestos fibres.     

Development of a new water sterilization device with a 365 nm UV-LED

Ultraviolet (UV) irradiation is an effective disinfection method. In sterilization equipment, a low-pressure mercury lamp emitting an effective germicidal UVC (254 nm) is used as the light source. However, the lamp, which contains mercury, must be disposed of at the end of its lifetime or following damage due to physical shock or vibration. We investigated the suitability of an ultraviolet light-emitting diode at an output wavelength of 365 nm (UVA-LED) as a sterilization device, comparing with the other wavelength irradiation such as 254 nm (a low-pressure mercury lam) and 405 nm (LED). We used a commercially available UVA-LED that emitted light at the shortest wavelength and at the highest output energy. The new sterilization system using the UVA-LED was able to inactivate bacteria, such as Escherichia coli DH5α, Enteropathogenic E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis. The inactivations of the bacteria were dependent on the accumulation of UVA irradiation. Taking advantage of the safety and compact size of LED devices, we expect that the UVA-LED sterilization device can be developed as a new type of water sterilization device     

Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer?

Shutter‐speed pharmacokinetic analysis of dynamic‐contrast‐enhanced (DCE)‐MRI data allows evaluation of equilibrium inter‐compartmental water interchange kinetics. The process measured here – transcytolemmal water exchange – is characterized by the mean intracellular water molecule lifetime (τ_i). The τ_i biomarker is a true intensive property not accessible by any formulation of the tracer pharmacokinetic paradigm, which inherently assumes it is effectively zero when applied to DCE‐MRI. We present population‐averaged in vivo human breast whole tumor τ_i changes induced by therapy, along with those of other pharmacokinetic parameters. In responding patients, the DCE parameters change significantly after only one neoadjuvant chemotherapy cycle: while K^trans (measuring mostly contrast agent (CA) extravasation) and k_ep (CA intravasation rate constant) decrease, τ_i increases. However, high‐resolution, (1 mm)², parametric maps exhibit significant intratumor heterogeneity, which is lost by averaging. A typical 400 ms τ_i value means a trans‐membrane water cycling flux of 10¹³ H₂O molecules s^?1/cell for a 12 µm diameter cell. Analyses of intratumor variations (and therapy‐induced changes) of τ_i in combination with concomitant changes of v_e (extracellular volume fraction) indicate that the former are dominated by alterations of the equilibrium cell membrane water permeability coefficient, P_W, not of cell size. These can be interpreted in light of literature results showing that τ_i changes are dominated by a P_W(active) component that reciprocally reflects the membrane driving P‐type ATPase ion pump turnover. For mammalian cells, this is the Na⁺,K⁺‐ATPase pump. These results promise the potential to discriminate metabolic and microenvironmental states of regions within tumors in vivo, and their changes with therapy. © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.     

Hydrogen rich water protects against myocardial ischemia/reperfusion injury in rats北大核心

BACKGROUND: Increasing evidence has indicated that low-concentration hydrogen or hydrogen rich water or hydrogen saturated saline exerts a protective effect on various diseases, such as myocardial ischemia/reperfusion injury. OBJECTIVE: To explore the protective effect of hydrogen rich water on myocardial ischemia/reperfusion injury. METHODS: Forty-eight Wistar rats were equally randomized into control and hydrogen-rich groups, and then subdivided into ischemic preconditioning, ischemia, and ischemia/reperfusion groups (n=8 rats in each subgroup). The myocardial ischemia/reperfusion model was established in the heart of each rat by the following procedures: reverse perfusion for 10 minutes, room temperature for 20 minutes, and reperfusion for 20 minutes. The control rats was perfused with pre-oxygenated (95% O2 plus 5% CO2) 37 ℃ K-R solution and the hydrogen-rich group was perfused with pre-oxygen-equilibrated (95% O2 plus 5% CO2) 37 ℃ K-R solution plus hydrogen-rich water (0.6 mmol/L, pH=7.3). Subsequently, the heart was removed, the pathological changes of the myocardial tissues were observe by hematoxylin-eosin staining, the activities of lactic dehydrogenase and creatine kinase in the myocardial tissues were determined, and the levels of tumor necrosis factor-α and interleukin-1β were detected by ELISA. RESULTS AND CONCLUSION: In the control group, the activity of lactic dehydrogenase at the ischemic and ischemia/reperfusion stages was significantly higher than that at the ischemic preconditioning stage (P < 0.05), and the activity of creatine kinase at the ischemia/reperfusion stage was significantly higher than that at the ischemic preconditioning and ischemic stages (P < 0.05). In the hydrogen-rich group, there was no significant difference in the activities of lactic dehydrodenase and creatine kinase at each stage, but the activities of at the ischemia/reperfusion stage was significantly lower than those in the control group (P < 0.05). In the two groups, the order of the levels of tumor necrosis factor-α and interleukin-1β was as follows: the ischemia/reperfusion stage > ischemic stage > ischemic preconditioning stage (P < 0.05). The levels of above factors in the hydrogen-rich group were significantly lower than those in the control group (P < 0.05). Our findings imply that hydrogen rich water has protective effect on myocardial ischemia/reperfusion injury of the rat hearts in vitro, which may be by reducing the expression of tumor necrosis factor-α and interleukin-1β, and further alleviating the inflammatory response. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Oil–water biphasic parallel flow for the precise patterning of metals and cells

Fluidic patterning is a convenient and versatile tool for the patterning of materials, cells and microstructures on surface and in microchannels. However, its performance is usually limited by transverse diffusion between fluid streams. It would blur the boundary and deteriorate the precision of patterns. In this paper, we adopted geometric confinement to generate biphasic parallel flow that is constituted of oil and water. Since there is minimum transverse diffusion in biphasic parallel flow, the performance of fluid patterning is expected to be improved. The results show that the metal (Silver and Chromium) patterns have distinct boundary and well-controlled geometry in comparison with that by conventional laminar flow patterning. Furthermore, the high biocompatibility of oil phase (perfluorodecalin, PFD) enables the precise patterning of viable bacteria inside microchannels. Our work demonstrated a new route of using biphasic parallel flow to patterning, which would serve wide applications in prototyping and research settings.     

Influence of water/O₂ plasma treatment on cellular responses of PCL and PET surfaces

In this study, low pressure water/O? plasma treatment was performed in order to obtain COOH functionalities on the surface of poly-ε-caprolactone (PCL) membranes as well as non-woven polyester fabric (NWPF) discs. The plasma treatments were performed in a cylindrical, capacitively coupled RF-plasma-reactor and then following steps were performed: in situ (oxalyl chloride vapors) gas/solid reaction to convert -OH functionalities into -COCl groups; and hydrolysis under open laboratory conditions using air moisture for final-COOH functionalities. COOH and OH functionalities on modified surfaces were detected quantitatively by using fluorescent labeling technique and an UVX 300G sensor. Electron spectroscopy for chemical analysis (ESCA) was used to evaluate the relative surface atomic compositions and the carbon and oxygen linkages located in non-equivalent atomic positions of untreated and modified surfaces. Atomic force microscope (AFM) analysis showed that nanoscale features of the PCL surfaces are dramatically changed during the surface treatments. Scanning electron microscopy (SEM) results indicated the changes in the relatively smooth appearance of the untreated NWPF discs after the plasma treatment. Periodontal ligament (PDL) fibroblasts were used in cell culture studies. Cell culture results showed that plasma treated PCL membranes and NWPF discs were favorable for the PDL cell spreading, growth and viability due to the presence of functional groups and/or nanotopographies on their surfaces.     

Water, water everywhere...but how can you make sure it's safe to drink?

Cryptosporidium is an opportunistic parasitic infection causing diarrhea, headache, abdominal cramping, vomiting, low-grade fever and sometimes death. It caused illness in 400,000 people in Milwaukee in 1993, and one hundred people died, the majority of them were living with AIDS. Since then, the Centers for Disease Control and Prevention (CDC) has issued water-safety guidelines for immunocompromised people. Boiling water will kill the cryptosporidium cysts, but people need to be aware that brushing their teeth or using ice cubes from untreated water could expose them to the parasite. Bottled water is not all safe; only that which is filtered in accordance with ANSI/NSF (American National Standards Institute/National Sanitation Foundation) Standard 53 will ensure safety. Home water filters must meet the requirements of the same standard. Currently available water filters under $200 are listed, and people are cautioned to exercise caution and wear gloves when changing the filters to prevent cryptosporidium exposure.     

Salt–water imbalance and fluid overload in hemodialysis patients: a pivotal role of corin

Clinical and Experimental Medicine - Natriuretic peptides (NP) play a key role in regulation of salt and water balance. Corin, a serine protease which activates NP, plays a key role in regulation...     

Effect of contrast water therapy duration on recovery of cycling performance: a dose�Cresponse study

This study investigated whether contrast water therapy (CWT) has a dose?Cresponse effect on recovery from high-intensity cycling. Eleven trained male cyclists completed four trials, each commencing with a 75-min cycling protocol containing six sets of five 15-s sprints and three 5-min time-trials in thermoneutral conditions. Ten minutes post-exercise, participants performed one of four recovery protocols: CWT for 6?min (CWT6), 12?min (CWT12), or 18?min (CWT18) duration, or a seated rest control trial. The CWT commenced in hot water (38.4?±?0.6°C) and alternated between hot and cold water (14.6?±?0.3°C) every minute with a 5-s changeover. The cycling protocol was repeated 2?h after completion of exercise bout one. Prior to exercise bout two, core temperature was lower in CWT12 (?0.19?±?0.14°C, mean?±?90% CL) and CWT18 (?0.21?±?0.10°C) than control. Compared with control, CWT6 substantially improved time-trial (1.5?±?2.1%) and sprint performance (3.0?±?3.1%), and CWT12 substantially improved sprint total work (4.3?±?3.4%) and peak power (2.7?±?3.8%) in exercise bout two. All CWT conditions generally improved thermal sensation, whole body fatigue and muscle soreness compared with control, but no differences existed between conditions in heart rate or rating of perceived exertion. In conclusion, CWT duration did not have a dose?Cresponse effect on recovery from high-intensity cycling; however, CWT for up to 12?min assisted recovery of cycling performance.