Metal-ligand cross-link strategy engineered iron-doped dopamine-based superstructure as peroxidase-like nanozymes for detection of glucose.

Nanozymes are nanomaterials with mimetic enzyme properties and the related research has attracted much attention. It is of great value to develop methods to construct nanozymes and to study their application in bioanalysis. Herein, the metal-ligand cross-linking strategy was developed to fabricate superstructure nanozymes. This strategy takes advantage of being easy to operate, adjustable, cheap, and universal. The fabricated superstructure nanozymes possess efficient peroxidase-like catalytic activity. The enzyme reaction kinetic tests demonstrated that for TMB and H2O2, the Km is 0.229 and 1.308 mM, respectively. Furthermore, these superstructure nanozymes are applied to highly efficient and sensitive detection of glucose. The linear range for detecting glucose is 20-2000 µM, and the limit of detection is 17.5 µM. Furthermore, mechanistic research illustrated that this integrated system oxidizes glucose to produce hydrogen peroxide and further catalyzes the production of ·OH and O2·-, which results in a chromogenic reaction of oxidized TMB for the detection of glucose. This work could not only contribute to the development of efficient nanozymes but also inspire research in the highly sensitive detection of other biomarkers.

Casein nanoparticles as oral delivery carriers of mequindox for the improved bioavailability.

Mequindox (Meq) is a promising broad-spectrum antibacterial agent, but the clinical application of Meq has been hampered by its low oral bioavailability. Casein (Cas) can bind to a variety of poorly water-soluble drugs to improve their water solubility through a micellar solubilization mechanism. Here, a low-cost and convenient method was introduced to prepare mequindox-loaded casein nanoparticles (Meq-Cas). Meq-Cas was characterized by several methods including differential scanning calorimetry (DSC), X-ray diffraction (XRD), and fourier transform infrared (FTIR) to illuminate the mutual effect between the drug and carriers. Meq-Cas presented nearly spherical nanoparticles with smooth surfaces and its mean particle size was lower than untreated Cas. Meq-Cas showed a nearly complete release of Meq, which displayed a biphasic drug release pattern in both phosphate-buffered solution (PBS) and simulated gastric fluid (SGF). The relative oral bioavailability of Meq-Cas was found to be about 1.20 times higher than that of the animals treated with Meq suspension (control). These results suggest that Cas is a good candidate to load in Meq for pharmaceutical purposes.

Protective effect of spermidine on salt stress induced oxidative damage in two Kentucky bluegrass (Poa pratensis L.) cultivars.

To improve the salinity tolerance of turfgrass and investigate the effect of spermidine (Spd) on antioxidant metabolism and gene expression under salinity stress condition, exogenous Spd was applied before two kentucky bluegrass (Poa pratensis L.) cultivars ('Kenblue' and 'Midnight') were exposed to 200 mM sodium chloride (NaCl) stress for 28 d. Salinity stress decreased the turfgrass quality, increased the content of malonyldialdehyde (MDA), superoxide anion (O2(·-)) and hydrogen peroxide (H2O2), and enhanced activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD) and ascorbate peroxidase (APX) and isozymes intensity in both cultivars. In addition, the expression level of Cu/ZnSOD was down-regulated in 'Kenblue' but up-regulated in 'Midnight' after salt treatment. Salinity stress also enhanced the expression of APX but inhibited the expression of CAT and POD in both cultivars. Exogenous Spd treatment alleviated the salinity-induced oxidative stress through decreasing MDA, H2O2 and O2(·-) contents in both cultivars. Besides, exogenous Spd further enhanced the activities of SOD, CAT, POD and APX accompanied with the increased intensity of specific isozymes of SOD, CAT and APX in both cultivars and POD in 'Kenblue'. Moreover, Spd further up-regulated expression levels of Cu/ZnSOD and APX, but down-regulated those of CAT and POD in both cultivars. These results indicated that exogenous Spd might improve turfgrass quality and promote the salinity tolerance in the two cultivars of kentucky bluegrass through reducing oxidative damages and increasing enzyme activity both at protein and transcriptional levels.

Methods of patient warming during abdominal surgery.

BACKGROUND: Keeping abdominal surgery patients warm is common and warming methods are needed in power outages during natural disasters. We aimed to evaluate the efficacy of low-cost, low-power warming methods for maintaining normothermia in abdominal surgery patients. METHODS: Patients (n = 160) scheduled for elective abdominal surgery were included in this prospective clinical study. Five warming methods were applied: heated blood transfusion/fluid infusion vs. unheated; wrapping patients vs. not wrapping; applying moist dressings, heated or not; surgical field rinse heated or not; and applying heating blankets or not. Patients' nasopharyngeal and rectal temperatures were recorded to evaluate warming efficacy. Significant differences were found in mean temperatures of warmed patients compared to those not warmed. RESULTS: When we compared temperatures of abdominal surgery patient groups receiving three specific warming methods with temperatures of control groups not receiving these methods, significant differences were revealed in temperatures maintained during the surgeries between the warmed groups and controls. DISCUSSION: The value of maintaining normothermia in patients undergoing abdominal surgery under general anesthesia is accepted. Three effective economical and practically applicable warming methods are combined body wrapping and heating blanket; combined body wrapping, heated moist dressings, and heating blanket; combined body wrapping, heated moist dressings, and warmed surgical rinse fluid, with or without heating blanket. These methods are practically applicable when low-cost method is indeed needed.