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Fine porous ammonium perchlorate (PAP) has small holes in its crust, and the voids in the particles are connected to the outside. The porosity of PAP results in fine bubble contamination in a propellant because the voids in PAP cannot be completely charged with a binder. Fine bubble contamination can improve the burning rate characteristics of an ammonium perchlorate (AP) propellant. The influence of the porosity of PAP on the burning characteristics of an ammonium nitrate (AN)/AP propellant and the effect of Fe2O3 as a catalyst on them were investigated in this study. The void fraction of the propellant increased with increasing mass ratio between AP and all oxidizers (ξ) and ranged from 1.3 % to 3.2 %. The porosity of PAP increased the burning rate of AN/AP propellants. This effect increased with decreasing pressure and was independent of ξ. However, porosity had minimal influence on the burning rate of AN/AP propellants with Fe2O3. The effect of the catalyst on the increase in the burning rate due to the porosity of PAP was influenced by pressure and ξ. The effect on the AN/AP propellant was greatest when ξ was in the 0.5–0.6 range. [ABSTRACT FROM AUTHOR]

Background: Symptoms of choledochal cysts sometimes persist or become exacerbated. As preoperative management for patients with these cysts, we prospectively employed endoscopic drainage, based on the theory that protein plugs cause symptoms by obstructing the pancreatobiliary ducts. Methods: Children with choledochal cysts underwent endoscopic retrograde cholangiopancreatography (ERCP). When ERCP showed compaction with filling defects in patients with persistent or worsening symptoms (study patients), the placement of a short biliary stent tube was attempted for drainage. The clinical and ERCP findings of the study patients were compared with those of patients who were asymptomatic at ERCP (asymptomatic patients). Results: There were 13 study patients (median age 2.9 years) and 41 asymptomatic patients (4.7 years) enrolled in the study between August 2005 and February 2011. Study patients more frequently had jaundice and elevated transaminase levels. ERCP showed that all study patients had obstruction or compacted filling defects in the common channel or the narrow segment distal to the cyst. Insertion of a stent tube was successful in 11 patients. Symptoms were relieved soon after biliary drainage. Surgery revealed that the obstructing materials were protein plugs, except in one case, which involved fatty acid calcium stones. Conclusions: These results support the protein plug theory. Endoscopic short-tube stenting is adequate and effective as preoperative management. [ABSTRACT FROM AUTHOR]

While myocardial ischaemia enhances the cardiotoxicity of local anaesthetics, the pharmacological background remains unclear. Cardiolipin ( CL) localized in mitochondrial membranes is possibly the site of cardiotoxic action of local anaesthetics and peroxynitrite is produced by cardiac ischaemia and reperfusion. We verified the hypothetic mechanism that local anaesthetics may interact with CL-containing biomembranes to change the membrane biophysical property and their membrane interactions may be increased by peroxynitrite. Biomimetic membranes were prepared with different phospholipids and cholesterol of varying compositions. The membrane preparations were reacted with peroxynitrite of pathologically relevant concentrations and local anaesthetics (bupivacaine and lidocaine) of a cardiotoxic concentration separately or in combination. Changes in membrane fluidity were determined by measuring fluorescence polarization. Peroxynitrite decreased the fluidity of biomimetic membranes at 0.1-10 μM with the relative potency being CL>1-stearoyl-2-arachidonoylphosphatidylcholine>1,2-dipalmitoylphosphatidylcholine-constituting membranes, indicating the lipid peroxidation-induced membrane rigidification determined by the unsaturation degree of membrane lipids. When treated with 0.1-10 μM peroxynitrite, biomimetic membranes were more rigid with elevating the CL content from 0% to 30 mol%, suggesting that CL is a primary target of peroxynitrite. Bupivacaine and lidocaine fluidized at 200 μM biomimetic membranes containing 10 mol% CL and their effects were increased by pre-treating the membranes with 0.1 and 1 μM peroxynitrite. Cardiotoxic bupivacaine and lidocaine increasingly interact with CL-containing mitochondria model membranes which are relatively rigidified by peroxynitrite. Such an increasing membrane interaction may be, at least in part, responsible for the local anaesthetic cardiotoxicity enhanced by myocardial ischaemia. [ABSTRACT FROM AUTHOR]

Cigarette smoking and alcohol consumption possibly affect platelet functions. To verify the hypothesis that some α-, β-, and γ- carboline components in cigarette smoke and alcoholic beverages may change platelet aggregability, their effects on human platelets were determined by aggregometry together with investigating their membrane effects by turbidimetry. Carbolines inhibited platelet aggregation induced by five agents with the potency being 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole > 3-amino- 1-methyl-5H-pyrido[4,3-b]indole > 1-methyl-9H-pyrido[3,4-b]indole. The most potent 3-amino-1,4-dimethyl-5H-pyrido[4,3- b]indole showed 50% aggregation-inhibitory concentrations of 6-172 μM. Both γ-carbolines interacted with phosphatidylcholine membranes to lower the lipid phase transition temperature with the potency correlating to the antiplatelet activity, suggesting that the interaction with platelet membranes to increase their fluidity underlies antiplatelet effects. Given their possible concentration and accumulation in platelets, γ- and β-carbolines would provide cigarette smokers and alcohol drinkers with reduced platelet aggregability, and they may be responsible for the occurrence of hemorrhagic diseases associated with heavy smoking and alcoholics. [ABSTRACT FROM AUTHOR]

Background: We applied a new concept of 'image overlay surgery' consisting of the integration of virtual reality (VR) and augmented reality (AR) technology, in which dynamic 3D images were superimposed on the patient's actual body surface and evaluated as a reference for surgical navigation in gastrointestinal, hepatobiliary and pancreatic surgery. Methods: We carried out seven surgeries, including three cholecystectomies, two gastrectomies and two colectomies. A Macintosh and a DICOM workstation OsiriX were used in the operating room for image analysis. Raw data of the preoperative patient information obtained via MDCT were reconstructed to volume rendering and projected onto the patient's body surface during the surgeries. For accurate registration, OsiriX was first set to reproduce the patient body surface, and the positional coordinates of the umbilicus, left and right nipples, and the inguinal region were fixed as physiological markers on the body surface to reduce the positional error. Results: The registration process was non-invasive and markerlesss, and was completed within 5 min. Image overlay navigation was helpful for 3D anatomical understanding of the surgical target in the gastrointestinal, hepatobiliary and pancreatic anatomies. The surgeon was able to minimize movement of the gaze and could utilize the image assistance without interfering with the forceps operation, reducing the gap from the VR. Unexpected organ injury could be avoided in all procedures. In biliary surgery, the projected virtual cholangiogram on the abdominal wall could advance safely with identification of the bile duct. For early gastric and colorectal cancer, the small tumors and blood vessels, which usually could not be found on the gastric serosa by laparoscopic view, were simultaneously detected on the body surface by carbon dioxide-enhanced MDCT. This provided accurate reconstructions of the tumor and involved lymph node, directly linked with optimization of the surgical procedures. Conclusions: Our non-invasive markerless registration using physiological markers on the body surface reduced logistical efforts. The image overlay technique is a useful tool when highlighting hidden structures, giving more information. [ABSTRACT FROM AUTHOR]

Background/Purpose: We investigated the feasibility of new carbon dioxide-enhanced virtual multidetector computed tomography (MDCT) cholangiopancreatography (CMCP) for intraluminal exploration in 73 patients with hepatobiliary and pancreatic disease. Methods: CMCP was performed via a percutaneous or transpapillary drainage tube, and, synchronously, intravenous contrast material was employed for virtual angiography; three-dimensional (3D) virtual reality was incorporated using OsiriX and Fovia applications. The capability of carbon dioxide to delineate the biliary and pancreatic system was evaluated. Results: All CMCPs showed complete technical success; complications including pancreatitis or pain never occurred. The incidences of visible third- and fourth-order biliary branches were 100 and 86.0%. The capability of carbon dioxide to pass an obstruction through an occluded hilar bile duct malignancy was 80.0%; it provided feasible information on additional bile duct segments. The full extent of the gallbladder was depicted in 72.7% of the studies. Minimum 2-mm lesions of biliary stones or gallbladder polyps were clearly detected. The main or second-order pancreatic ducts were visible in 100 and 83.3% of the studies, respectively. Carbon dioxide enabled the replacement of mucin and pancreatic juice and facilitated the detection of cystic lesions of intraductal papillary-mucinous neoplasm (IPMN) in 75.0% of the studies. We succeeded in achieving 3D spatial recognition of vascular structures in the cholangiopancreatic region, through the fusion of CMCP and 3DCT arteriography and venography in a single image scanning, and radiation time was decreased. This combined modality proved to be feasible for planning operations and for image-guided navigated surgery in the resection of a malignancy. Conclusions: To our knowledge, this is the first report to demonstrate the diagnostic accuracy of carbon dioxide MDCT cholangiopancreatography and the use of this modality for depicting biliary, pancreatic, and fusion blood vessels simultaneously. Carbon dioxide possesses many advantages over conventional iodinated contrast agents, and it might replace more invasive diagnostic measures in the near future. [ABSTRACT FROM AUTHOR]

We compared the effects of ropivacaine, bupivacaine and mepivacaine on membrane lipids in an attempt to determine the anaesthetic mechanism of ropivacaine with structure-dependent potency. The membrane effects were determined by measuring anaesthetic-induced changes in the phase transition temperature and the fluorescence polarization of liposomal membranes prepared with cholesterol and phosphatidylcholine. Bupivacaine, ropivacaine and mepivacaine depressed the membrane lipid phase transition and decreased the polarization of liposomal membranes at 0.06251.0 mg/mL, indicating that these anaesthetics fluidize membranes at concentrations lower than those in clinical use. Ropivacaine and bupivacaine were effective in fluidizing the membrane core rather than the membrane surface, whereas mepivacaine was a membrane fluidizer acting equally on both regions. In the comparison of membrane fiuidization at an equimolar concentration (3.0 mmol/L), ropivacaine was found to be less potent than bupivacaine and more potent than mepivacaine. This membrane-fluidizing potency was also consistent with the hydrophobic properties of these substances evaluated by reversed-phase chromatography. Structure-dependent membrane fluidization associating with hydrophobicity appears to underlie the local anaesthetic effect of ropivacaine as well as those of bupivacaine and mepivacaine. [ABSTRACT FROM AUTHOR]

Since several anti-cancer drugs interact with cell membrane lipids, the effects of anti-cancer dietary factors on liposomal membranes with different lipid composition were comparatively studied by measuring fluorescence polarization. Fluidity was imparted on both hydrophobic and hydrophilic regions of lipid bilayers by decreasing cholesterol and increasing unsaturated phosphatidylcholine in membranes. At 0.625–10 μM, (–)-epigallocatechin gallate, genistein, apigenin, resveratrol and a reference anti-cancer drug, doxorubicin, rigidified the tumor cell model membranes consisting of 20 mol% cholesterol and 80 mol% phosphatidylcholine with the acyl chain 18:1/16:0 ratio of 1.0, but not daidzein. They were more effective on the membrane core than the membrane surface. Quercetin showed a biphasic effect on the hydrophobic regions of membrane lipid bilayers to rigidify above 5 μM and fluidize below 2.5 μM. In contrast, anti-cancer dietary factors and doxorubicin were not or much less effective in rigidifying the normal cell model membranes consisting of 40 mol% cholesterol and 60 mol% phosphatidylcholine with the acyl chain 18:1/16:0 ratio of 0.5. The membrane-rigidifying effects were greater depending on a decrease of the cholesterol/phosphatidylcholine ratio and an increase of the phosphatidylcholine unsaturation degree. Membrane-active dietary factors and doxorubicin inhibited the growth of mouse myeloma cells at 10–100 μM, while the growth inhibition by membrane-inactive daidzein was relatively weak. Anti-cancer dietary factors appear to act on more fluid membranes like tumor cells as well as doxorubicin to induce rigidification, especially in the hydrocarbon core of membrane lipids, which is determined by the composition of cholesterol and unsaturated phospholipids. [ABSTRACT FROM AUTHOR]