The role of protein kinase C in ischemic tolerance induced by hyperoxia in rats with stroke

Recent studies suggest that normobaric hyperoxia (HO) protects the rat brain from ischemia reperfusion (IR) injury. Protein kinase C (PKC) is a key signaling molecule involved in protection against IR injury but its role in protective effect of HO in brain injury in unknown. In this study we attempted to see if PKC is involved in the effect of HO. Rats were divided into four main experimental groups. The first two were exposed to 95 % oxygen (HO) in a chamber 4 h/day for 6 consecutive days. Each of these groups had a control group exposed to 21 % oxygen. To investigate the role of PKC during HO, chelerythrin chloride (CHEL, 1 mg/kg/day), a PKC inhibitor, or its vehicle was given to animals for 6 days. After 24 h, the rats were subjected to 60 min of right middle cerebral artery occlusion (MCAO). After 24 h reperfusion neurological deficit scores, infarct volume, brain edema and blood–brain Barrier (BBB) permeability were assessed. HO decreased the infarct volume and brain edema in comparison with controls. PKC inhibition was associated with a significant increase in infarct size in both HO and control animals. PKC inhibition was unable to change brain edema in the experimental groups. Both HO and PKC inhibition reduced the BBB permeability within 24 h post occlusion of middle cerebral artery. Although both HO and PKC inhibition were associated with inhibition of BBB permeability during ischemic brain injury in rats, the neuroprotective effect of HO was independent of PKC in the MCAO model

HYPEROXIC PRECONDITIONING FAILS TO CONFER ADDITIONAL PROTECTION AGAINST ISCHEMIA-REPERFUSION INJURY IN ACUTE DIABETIC RAT HEART

Experimental studies show that detrimental effects of ischemia-reperfusion (I/R) injury can be attenuated by hyperoxic preconditioning in normal hearts, however, there are few studies about hyperoxia effects in diseased myocardium. The present study was designed to assess the cardioprotective effects of hyperoxia pretreatment (≥ 95 % O2) in acute diabetic rat hearts. Normal and one week acute diabetic rats were either exposed to 60 (H60) and 180 (H180) min of hyperoxia or exposed to normal atmospheric air (21 % O2). Then hearts were isolated immediately and subjected to 30 min of regional ischemia followed by 120 min of reperfusion. Infarct size, cardiomyocyte apoptosis, enzymes release and ischemia induced arrhythmias were determined. Heart of diabetic control rats had less infarct size and decreased LDH and CK-MB release compared to normal hearts. 60 and 180 min of hyperoxia reduced myocardial infarct size and enzymes release in normal hearts. 180 min of hyperoxia also decreased cardiomyocytes apoptosis in normal state. On the other hand, protective values of hyperoxia were not significantly different in diabetic hearts. Moreover, hyperoxia reduced severity of ventricular arrhythmias in normal rat hearts whereas; it did not confer any additional antiarrhythmic protection in diabetic hearts. These findings suggest that diabetic hearts are less susceptible to ischemia-induced arrhythmias and infarction. Hyperoxia greatly protects rat hearts against I/R injury in normal hearts, however, it could not provide added cardioprotective effects in acute phase of diabetes

Biohydrogen Production Through Mixed Culture Dark Anaerobic Fermentation of Industrial Waste

Industrial organic waste from food processing, livestock production, brewery, bakery, and other related industries is a renewable substrate for anaerobic digestion to produce methane (CH4) or with some process manipulation and control to produce hydrogen (H2). Type of waste, its strength, presence of any toxic compounds, and other specific characteristics affect the operating conditions such as organic loading rate, hydraulic retention time, substrate pretreatment, as well as the yield and the rate of H2 production from industrial waste. Therefore, they need to be optimized for each waste. Research is required on the modeling, cost analysis, economic evaluation, comparative studies about the effect of bioreactor design, as well as on combining several industrial wastes to prepare a well-balanced substrate for H2-producing mixed culture dark fermentation

Diagram of the custom-built whole-body plethysmograph.

<p>The apparatus included a cylindrical chamber made of transparent Plexiglas. Room air was continuously pumped (4 L/min) into the chamber. A plastic Y-connector was connected to chamber's outlet. One of the exit ports was linked to one input of a differential pressure transducer, and the other input being exposed to the room air. Another port Y-connector was connected to a one input of CO2 sensor. The other input of the CO2 sensor was opened to the room air. The respiratory signals were acquired at the sampling rate of 1 kHz.</p

Effect of Rho-kinase inhibition on synchronization between IBI and RV.

<p>* p<0.01 compared to saline group. Data was analyzed by one-way ANOVA with the Bonferroni post-test. IBI, inter-breath interval; RV, respiratory volume; Cross-SampEn, cross-sample entropy.</p

mRNA expression of TNF-α (a) and IL-13 (b) in the lung of experimental groups.

<p>* p<0.05 and ** p<0.01 compared to Saline group. Data were analyzed by a Kruskal–Wallis test with a Dunn’s post-test.</p