Aqueous-System-Enabled Spray-Drying Technique for the Synthesis of Hollow Polycrystalline ZIF-8 MOF Particles.

Zeolitic imidazolate framework-8 shares the same topology with sodalite zeolite but consists of Zn nodes bridged by imidazolate linkers to form a neutral open-framework structure. ZIF-8 has been recognized as a unique molecular sieving material with a flexible framework enabling interesting "gate-opening" functionality. Controlling the crystal size and shape is crucial for regulating the structural flexibilities and mass transport properties. The present study demonstrates that an aqueous-system-enabled spray-drying process enables the shape engineering of ZIF-8 with a hollow polycrystalline structure. It is notable that our synthesis route produces an amorphous zinc complex compound, which possesses a continuous random network partially with crystalline fillers, after spray drying followed by an amorphous-to-crystal transition via activation treatment using polar organic solvents. The size of primary ZIF-8 crystals consisting of secondary polycrystals depends on the kind of the organic solvent. The macro-/microscopic structures of hollow polycrystalline ZIF-8 significantly structurally enhanced the adsorption capacity and uptake rate. The large-scale, rapid production and enhanced adsorption performances make this continuous method a very promising candidate for industrial applications and shaping of MOF.

Substrate-dependent modulation of oxidative phosphorylation in isolated mitochondria following in vitro hypoxia and reoxygenation injury.

BACKGROUND/OBJECTIVES: Previous studies using isolated mitochondria have provided new insight into the mechanisms and interventions for ischemia and reperfusion (I/R) injury. In in vitro experiments involving isolated mitochondria, hypoxia and reoxygenation (H/R) has been widely used to mimic I/R injury. However, in in vitro H/R mitochondrial experiments, the effects of various substrates on mitochondrial oxidative phosphorylation are unclear. In the present study, the effects of in vitro I/R injury on mitochondrial oxidative phosphorylation under different substrate conditions were investigated. METHODS: Hypoxia was achieved following complete consumption of oxygen by mitochondria isolated from rat heart tissue in an experimental chamber. The H/R protocol involved 30 min hypoxia followed by 15 min reoxygenation in a chamber opened to the atmosphere. Mitochondrial respiration and respiratory control ratio (RCR) were measured. RESULTS: When pyruvate/malate were used as substrates, H/R significantly decreased state 3 respiration (28.2±12 nmol O2/min/mg protein) and RCR (2.7±0.8) compared with the control (121.4±32.5 nmol O2/mg protein/min and 7.8±1.2, respectively). In contrast, when succinate was used without rotenone, H/R significantly increased state 3 respiration (57.0±11.2 nmol O2/mg protein/min) and RCR (2.0±0.3) compared with the control (48.2±12.3 nmol O2/mg protein/min and 1.3±0.2, respectively). CONCLUSIONS: The present study demonstrated that mitochondrial oxidative phosphorylation can be modulated by H/R in vitro depending on substrate conditions.

[Anesthetic management of organ donation after brain death using continuous total hemoglobin measurement].

A 60-year-old woman declared brain dead was scheduled for organ donation. We continuously measured total hemoglobin values (SpHb) using a Radical-7 monitor (Masimo Co, Irvine, CA, USA) to maintain the functions of organs and oxygen delivery. At the start of surgery, the SpHb value was 9.3 g x dl(-1). Packed red blood cells were transfused immediately No anesthetics or opioids were used during the operation. Blood pressure suddenly decreased to below 80 mmHg because of bleeding, manipulation of organs, and/or compression of the vena cava. Six units of red blood cells and 900 ml of colloids were rapidly transfused with real-time monitoring of SpHb values. On cross-clamping of the aorta, the SpHb value increased up to 10.2 g x dl(-1). The heart, lungs, liver, pancreas, and kidneys were donated from the patient without organ dysfunction. The highlight of this case report is that anesthesiologists could use SpHb monitoring for management of hemodynamics in a brain-dead organ donor.

Heart rate variability during abdominal surgical manipulation under general and epidural anesthesia.

Anesthesiologists occasionally encounter bradycardia during abdominal surgery and recognize the phenomenon as a vagal reflex. The presence of bradycardia implies efferent vagal dominance in the autonomic nervous system during this vagal reflex. In this study, we investigated the effect of abdominal surgical manipulation on autonomic nervous activity, using heart rate variability analysis. Abdominal surgical manipulation decreased the heart rate and enhanced not only the high-frequency power (0.15-0.4 Hz) but also the low-frequency power (0.04-0.15 Hz) calculated from the power spectral density of heart rate variability. Our results suggest that both vagal tone and sympathetic tone could be activated during the vagal reflex caused by abdominal surgical manipulation.

[Anesthetic management of caesarean section using common iliac artery balloon occlusion in patients with placenta previa].

We report anesthetic management of caesarean section using common iliac artery balloon occlusion in 6 patients with placenta previa. Placenta previa might induce critical hemorrhage during caesarean section. We performed caesarean section safely, with preoperative placement of occlusive balloon catheters in the bilateral common iliac arteries. This technique provided satisfactory condition for control of bleeding during the operation. There was no perioperative complication in these patients. Common iliac artery balloon occlusion could reduce blood loss during caesarean section in patients with placenta previa.

Colloid solutions: a clinical update.

Albumin, dextran, gelatin, and hydroxyethyl starch (HES) solutions are colloids that efficiently expand the circulating blood volume. The administration of colloids restores the intravascular volume with minimal risk of tissue edema in comparison with crystalloid solutions alone. However, colloids are always given for surgical and critically ill patients. The type of the colloid, volumes applied, aggressiveness of fluid resuscitation, and the volume status at the initial phase of administration determine their clinical responses. The outcome after fluid resuscitation with various colloids in critically ill patients seems to be comparable according to systematic reviews. A randomized, adequately powered clinical trial comparing modern nonprotein colloid to albumin is still lacking. Rapidly degradable HES solutions have good hemodynamic effects, and the risk of adverse renal and coagulation effects, as well as allergic reactions, is minimal. The current investigation has also shown the beneficial effect of HES solution (especially HES 130/0.4) on inflammatory response, postoperative nausea and vomiting, and postoperative outcome. The indication of colloids with an assessment of the degree of hypovolemia and safety profiles should thus be taken into consideration before colloid administration.

Low-dose continuous infusion of landiolol can reduce adrenergic response during tracheal intubation in elderly patients with cardiovascular disease.

The objective of this study was to examine the effects of low-dose infusion of landiolol on hemodynamics during tracheal intubation in elderly patients with cardiovascular disease. The study population consisted of 30 patients with American Society of Anesthesiologists physical status II and III, aged 65-77 years, who were scheduled to undergo elective surgery under general anesthesia. Patients were randomly divided into two groups (n = 15 each): a control group, receiving normal saline, and a landiolol group, receiving landiolol at 30 µg/kg/min. After oxygenation, 1 µg/kg of fentanyl was injected intravenously, followed by continuous infusion of normal saline or landiolol for 5 min. General anesthesia was induced and maintained with target-controlled infusion of propofol at a blood concentration of 4 µg/ml and tracheal intubation was performed 3 min after vecuronium injection. Heart rate, blood pressure, and bispectral index were measured before and after tracheal intubation. Results showed that low-dose continuous infusion of landiolol is an effective and relatively safe method of preventing an intubation-induced adrenergic response in elderly patients with cardiovascular disease.