Effect of hypernatremia on injury caused by energy deficiency: role of T-type Ca2+ channel

Highly efficient oxidation of 2,2'-hydrazobis-isobutyronitrile to 2,2'-azobis-isobutyronitrile over a CrOx/TiO2 catalyst with hydrogen peroxide

Green oxidation of 2,2'-hydrazobis-isobutyronitrile (HAIBN) to 2,2'-azobis-isobutyronitrile (AIBN) over a recyclable solid catalyst was a significant challenge. A titanium dioxide-supported chromium oxide (CrOx/TiO2) catalyst was, for the first time, developed for oxidation of HAIBN with hydrogen peroxide and achieved complete conversion of HAIBN with a high (94.8%) yield of AIBN.

Mild halogenation of polyolefins using an N-haloamide reagent

A new methodology for the chlorination of PE and PP without the use of chlorine gas.

A highly selective and sensitive turn-on chemodosimeter for hypochlorous acid based on an iridium(III) complex and its application to bioimaging

A novel and easily accessible luminescent iridium(iii) complex [Ir(tpy)2(N^N)]PF6 (, tpy = 2-(p-tolyl)pyridine, N^N = 4-[(4-amino-3-nitrophenoxy)-methylene]-4'-methyl-2,2'-bipyridine) for the sensing of HOCl has been designed and synthesized. The detection strategy is based on the HOCl-promoted cleavage of the PET quenching 4-amino-3-nitrophenyloxy moiety of the weakly emissive complex , which gives rise to a highly luminescent complex [Ir(tpy)2(N^N')]PF6 (, N^N' = 4-hydroxymethyl-4'-methyl-2,2'-bipyridine). Comparisons of the absorption, emission and mass spectra of in the absence and presence of HOCl have all confirmed the transformation of to . Titration and competition experiments have revealed high sensitivity and high selectivity of for HOCl, respectively. Significantly, the feasibility of the sensor under physiological conditions enables the successful luminescent imaging of HOCl in HeLa cells.

Sodium levels of human pancreatic donors are a critical factor for determination of islet efficacy and survival

Organs from hypernatremia (elevated Na+) donors when used for transplantation have had dismal outcomes. However, islet isolation from hypernatremic donors for both transplantation and research applications has not yet been investigated. A retrospective analysis of in vivo and in vitro islet function studies was performed on islets isolated from hypernatremic (serum sodium levels≥160 meq/l) and normal control (serum sodium levels≤155 meq/l) donors. Twelve isolations from 32 hypernatremic and 53 isolations from 222 normal donors were randomly transplanted into diabetic NOD Scid mice. Sodium levels upon pancreas procurement were significantly elevated in the hypernatremia group (163.5±0.6 meq/l) compared with the normal control group (145.9±0.4 meq/l) (P<0.001). The postculture islet recovery rate was significantly lower in the hypernatremia (59.1±3.8%) group compared with the normal (73.6±1.8%) group (P=0.005). The duration of hypernatremia was inversely correlated with the recovery rate (r2=0.370, P<0.001). Furthermore, the percentage of successful graft function when transplanted into diabetic NOD Scid mice was significantly lower in the hypernatremia (42%) group compared with the normal control (85%) group (P<0.001). The ability to predict islet graft function posttransplantation using donor sodium levels and duration of hypernatremia was significant (ROC analysis, P=0.022 and 0.042, respectively). In conclusion, duration of donor hypernatremia is associated with reduced islet recovery postculture. The efficacy of islets from hypernatremia donors diminished when transplanted into diabetic recipients.

Combined hypoxia and sodium nitrite pretreatment for cardiomyocyte protection in vitro

Methods that increase cardiomyocyte survival upon exposure to ischemia, hypoxia and reoxygenation injuries are required to improve the efficacy of cardiac cell therapy and enhance the viability and function of engineered tissues. We investigated the effect of combined hypoxia/NaNO2 pretreatment on rat neonatal cardiomyocyte (CM), cardiac fibroblast, and human embryonic stem cell-derived CM (hESC-CM) survival upon exposure to hypoxia/reoxygenation (H/R) injury in vitro. Cells were pretreated with and without hypoxia and/or various concentrations of NaNO2 for 20 min, then incubated for 2 h under hypoxic conditions, followed by 2 h in normoxia. The control cells were maintained under normoxia for 4 h. Pretreatment with either hypoxia or NaNO2 significantly increased CM viability but had no effect on cardiac fibroblast viability. Combined hypoxia/NaNO2 pretreatment significantly increased CM viability but significantly decreased cardiac fibroblast viability. In rat neonatal CMs, cell death, as determined by lactate dehydrogenase (LDH) activity, was significantly reduced with hypoxia/NaNO2 pretreatment; and in hESC-CMs, hypoxia/NaNO2 pretreatment increased the BCL-2/BAX gene expression ratio, suggesting that hypoxia/NaNO2 pretreatment promotes cell viability by downregulating apoptosis. Additionally, we found a correlation between the prosurvival effect of hypoxia/NaNO2 pretreatment and the myoglobin content of the cells by comparing neonatal rat ventricular and atrial CMs, which express high and low myoglobin respectively. Functionally, hypoxia/NaNO2 pretreatment significantly improved the excitation threshold upon H/R injury to the level observed for uninjured cells, whereas pretreatment did not affect the maximum capture rate. Hence, hypoxia/NaNO2 pretreatment may serve as a strategy to increase CM survival in cardiac regenerative therapy applications and tissue engineering.