Toshihiro Sasaki

Heme Arginate Pretreatment Attenuates Pulmonary NF-κB and AP-1 Activation Induced by Hemorrhagic Shock via Heme Oxygenase-1 Induction

Hemorrhagic shock followed by resuscitation (HSR) induces oxidative stress that leads to acute lung injury. Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, is induced by oxidative stress and is thought to play an important role in the protection from oxidative tissue injuries. We previously demonstrated that HO-1 induction by heme arginate (HA), a strong inducer of HO-1, ameliorated HSR-induced lung injury and inflammation. Cellular redox state is known to modulate the DNA biding activity of the transcription factors; nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). In the present study, we treated rats with HA (30 mg/kg of hemin) 18 h prior to HSR and examined its effect on the DNA binding activity of NF-kappaB and AP-1 at 1.5 h after HSR. HSR significantly increased the DNA binding activity of NF-kappaB as well as AP-1, while HA pretreatment markedly attenuated the activities of these transcription factors. In contrast, administration of tin mesoporphyrin, a specific competitive inhibitor of HO activity, to HA-pretreated animals abolished the suppressive effect of HA on the activities of NF-kappaB and AP-1, and increased these activities to almost the same level as those in HSR animals. Our findings indicate that HA pretreatment can significantly suppress the increased activity of NF-kappaB and AP-1 induced by HSR by virtue of its ability to induce HO-1. Our findings also suggest that HO-1 induced by HA pretreatment ameliorates HSR-induced lung injury at least in part mediated through the suppression of the activities of these transcription factors.

Dynamic changes in cortical NADH fluorescence in rat focal ischemia: evaluation of the effects of hypothermia on propagation of peri-infarct depolarization by temporal and spatial analysis.

Suppression of peri-infarct depolarizations (PIDs) is one of the major mechanisms of hypothermic protection against transient focal cerebral ischemia. Previous studies have shown the lack of hypothermic protection against permanent focal ischemia. We hypothesized the lack of hypothermic protection was due to the poor efficacy in suppression of PIDs. To examine the hypothesis, we elucidated the effects of hypothermia on the manner of propagation of PIDs with temporal and spatial resolutions using NADH (reduced nicotinamide adenine dinucleotide) fluorescence images by illuminating the parietal-temporal cortex with ultraviolet light. Spontaneously hypertensive rats (n=14) were subjected to permanent focal ischemia by occlusion of the middle cerebral and left common carotid arteries. 2-h hypothermia (30 degrees C) was initiated before ischemia. Although hypothermia delayed the appearance of PIDs, it did not suppress their appearance. Furthermore, 54% of the PIDs enlarged the high-intensity area of NADH fluorescence in the hypothermia group, similar to the normothermia group (53%). The high-intensity area of NADH fluorescence widened by each PID was larger in the hypothermia group than in the normothermia group. These findings suggest that PIDs even in hypothermia are one of the major factors causing growth of infarction, emphasizing the importance of therapy that targets suppression of PIDs even during hypothermia.

Effect of nitrous oxide on neuronal damage and extracellular glutamate concentration as a function of mild, moderate, or severe ischemia in halothane-anesthetized gerbils.

Background:The effect of nitrous oxide on ischemic neuronal damage was quantitatively evaluated by use of logistic regression curves. Methods:Seventy-two gerbils were anesthetized with 1% halothane and randomly assigned to receive 70% nitrous oxide or 70% nitrogen. Forebrain ischemia was performed for 3, 5, or 7 min, and direct-current potential in the hippocampal CA1 region was recorded. Histologic outcome was evaluated 5 days later. Relations of neuronal damage with ischemic duration and duration of ischemic depolarization were determined by logistic regression curves. In some animals, extracellular glutamate concentration was measured every 60 s during forebrain ischemia. Results:Nitrous oxide increased neuronal damage only with 5 min of ischemia (nitrous oxide vs. nitrogen: 78.5 ± 23.0 vs. 37.3 ± 12.2%; P < 0.01). The percentages of neuronal damage with 3 and 7 min of ischemia were not different with or without nitrous oxide. Logistic regression curves indicated that nitrous oxide significantly increased neuronal damage during the period from 3.07 to 6.63 min of ischemia. Logistic regression curves also indicated that nitrous oxide increased neuronal damage in the condition of the same duration of ischemic depolarization. Nitrous oxide shortened the ischemic duration necessary for causing 50% neuronal damage by 0.82 min. Dynamic change in extracellular glutamate concentration was not different (mean maximum dialysate glutamate concentration: 4.29 ± 3.09 vs. 4.63 ± 1.83 &mgr;m). Conclusion:Administration of nitrous oxide caused an increase in ischemic neuronal damage, but a significant adverse effect was observed with a limited range of ischemic intervals.

Perioperative management center (Perio) for neurosurgical patients

Perioperative management is critical for positive neurosurgical outcomes. In order to maintain safe and authentic perioperative management, a perioperative management center (PERIO) was introduced to patients of our Neurosurgery Department beginning in June 2014. PERIO involves a multidisciplinary team consisting of anesthesiologists, dentists/dental hygienists/technicians, nurses, physical therapists, pharmacists, and nutritionists. After neurosurgeons decide on the course of surgery, a preoperative evaluation consisting of blood sampling, electrocardiogram, chest X-ray, and lung function test was performed. The patients then visited the PERIO clinic 7–14 days before surgery. One or two days before surgery, the patients without particular issues enter the hospital and receive a mouth cleaning one day before surgery. After surgery, postoperative support involving eating/swallowing evaluation, rehabilitation, and pain control is provided. The differences in duration from admission to surgery, cancellation of surgery, and postoperative complications between PERIO and non-PERIO groups were examined. Eighty-five patients were enrolled in the PERIO group and 131 patients in the non-PERIO group. The duration from admission to surgery was significantly decreased in the PERIO group (3.6 ± 0.3 days), compared to that in the non-PERIO group (4.7 ± 0.2 days). There was one cancelled surgery in the PERIO group and six in the non-PERIO group. Postoperative complications and the overall hospital stay did not differ between the two groups. The PERIO system decreased the duration from admission to surgery, and it is useful in providing high-quality medical service, although the system should be improved so as not to increase the burden on medical staff.