Applying patient characteristics, stent-graft selection, and pre-operative computed tomographic angiography data to a machine learning algorithm: Is endoleak prediction possible?

INTRODUCTION: This study aims to predict endoleak after endovascular aneurysm repair (EVAR) using machine learning (ML) integration of patient characteristics, stent-graft configuration, and a selection of vessel lengths, diameters and angles measured using pre-operative computed tomography angiography (CTA). METHODS: We evaluated 1-year follow-up CT scans (arterial and delayed phases) in patients who underwent EVAR for the presence or absence of an endoleak. We also obtained data on the patient characteristics, stent-graft selection, and preoperative CT vessel morphology (diameter, length, and angle). The extreme gradient boosting (XGBoost) for the ML system was trained on 30 patients with endoleaks and 81 patients without. We evaluated 5217 items in 111 patients with abdominal aortic aneurysms, including the patient characteristics, stent-graft configuration and vascular morphology acquired using pre-EVAR abdominal CTA. We calculated the area under the curve (AUC) of our receiver operating characteristic analysis using the ML method. RESULTS: The AUC, accuracy, 95% confidence interval (CI), sensitivity, and specificity were 0.88, 0.88, 0.79-0.97, 0.85, and 0.91 for ML applying XGBoost, respectively. CONCLUSIONS: The diagnostic performance of the ML method was useful when factors such as the patient characteristics, stent-graft configuration and vessel length, diameter and angle of the vessels were considered from pre-EVAR CTA. IMPLICATIONS FOR PRACTICE: Based on our findings, we suggest that this is a potential application of ML for the interpretation of abdominal CTA scans in patients with abdominal aortic aneurysms scheduled for EVAR.

Radiation dose reduction method combining the ECG-Edit function and high helical pitch in retrospectively-gated CT angiography.

INTRODUCTION: The purpose of this study was to demonstrate that dose reduction does not compromise image quality when combining high helical pitch (HP) and the ECG-Edit function during low HP retrospectively gated computed tomography angiography (CTA). METHODS: This study made use of a pulsating cardiac phantom (ALPHA 1 VTPC). The heart rate (HR) of the cardiac phantom was changed in five intervals, every 5 beats per minute (bpm), from 40 to 60 bpm. Evaluation of a range of HR was important because data loss might occur when combining a low HR and high HP. We performed retrospectively gated CTA scans five times using a low HP (0.16) and high HP (0.24), for each of the five HR intervals, using a 64-detector row CT scanner. The CT volume dose index (CTDIvol) was recorded from the CT console of each scan. For the images with data loss, data were repaired using the ECG-Edit function. We compared the CTDIvol, estimated cardiac phantom volume, and the visualization of the coronary ladder phantom between HP 0.16, with or without repaired HP 0.24, using the ECG-Edit function. RESULTS: Data loss occurred with a HR of 40 bpm and 45 bpm when using HP 0.24. The CTDIvol was reduced by approximately 33% with HP 0.24 when compared with HP 0.16. There were no significant differences in the mean cardiac motion phantom volume and visualization scores between HP 0.16 and with and without repaired HP 0.24 using the ECG-Edit function (p < 0.05). CONCLUSION: The ECG-Edit function is potential useful for repairing the lost data in patients with a low HR, and when combined with a high HP, it is possible to reduce the radiation dose by approximately 33%. IMPLICATIONS FOR PRACTICE: The ECG-Edit function and high HP may be a viable option in pediatric CTA studies.

Efficacy of the spiral flow generating extended tube during paediatric CCTA.

INTRODUCTION: To compare the computed tomography (CT) number for paediatric cardiac computed tomography angiography (CCTA) and visualisation score of the three-dimensional (3D) images using the conventional T-shaped extended tube (T-tube) and spiral flow-generating extended tube (spiral-tube) connected between the contrast injector and cannula. METHODS: In total, 108 patients suspected to have congenital heart disease (CHD) were considered for inclusion. We utilised the T-tube for intravenous contrast and spiral-tube in 54 patients each. Observers individually inspected randomized volume rendering images of the internal thoracic artery, each acquired from the with or without spiral-tube groups, using a four-point scale. We compared the mean CT number of the ascending aorta (AAO) and pulmonary artery (PA), contrast noise ratio (CNR), CT number for the AAO and PA enhancement ratio, and the visualisation scores between the groups. RESULTS: There were no significant differences in patient characteristics between the with or without spiral-tube groups (p > 0.05). The mean CT number ±standard deviation for the AAO and PA, and the CNR without or with spiral-tube groups were 441.2 ± 89.2 and 489.8 ± 86.1 HU for the AAO, 436.3 ± 100.6 and 475.3 ± 85.2 HU for the PA, and 9.5 ± 2.2 and 10.8 ± 2.4 for the CNR, respectively (p < 0.05). In the spiral-tube group, the CT number, CNR, and visualisations score of the 3D images were significantly higher for the AAO and PA than those in the T-tube group (p < 0.05). CONCLUSION: The spiral-tube proved to be beneficial in improving the CT number for the AAO and PA, CNR, and visualisation score compared with the conventional T-tube during paediatric CCTA. IMPLICATIONS FOR PRACTICE: The spiral-tube may allow the visualisation of smaller blood vessels than those visualised by the conventional T-tube for paediatric patients in CCTA.

Enhancement rate of venous phase to portal venous phase computed tomography and its correlation with ultrasound elastography determination of liver fibrosis.

INTRODUCTION: This study aimed to compare the correlation between the computed tomography (CT) enhancement rate of the venous to portal venous phase (VP-ER) and the extracellular volume (ECV) fraction with shear-wave ultrasound elastography (USE) findings in patients with liver fibrosis. METHODS: We included 450 patients with clinically suspected liver cirrhosis who underwent triphasic dynamic CT studies and USE. We compared the USE results with the unenhanced CT phase, with enhancement in the hepatic artery phase (HAP), portal venous phase (PVP), and venous phase (VP), and with the ECV fraction and the VP-ER. We also compared the area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the ECV fraction and VP-ER with that of the values obtained with USE. RESULTS: The VP-ER was the most highly correlated with the liver stiffness value determined with USE (Pearson's correlation coefficient: r = 0.37), followed by enhancement in the PVP (r = -0.25), CT number on unenhanced CT scans (r = -0.22), the ECV fraction (r = 0.19), enhancement in the VP (r = 0.059), and enhancement in the HAP (r = -0.023) (all p < 0.01). The VP-ER showed a significantly higher AUC than the ECV fraction (0.75 vs 0.62) when the liver stiffness was >15 kPa in USE studies (p = 0.04). CONCLUSION: Compared to the ECV fraction, the VP-ER is more useful for predicting all degrees of liver fibrosis on routine triphasic dynamic CT images. IMPLICATIONS FOR PRACTICE: Although improvement is needed, the VP-ER has a higher diagnostic ability for liver fibrosis than the ECV fraction in clinical practice.

Effect of injection duration on contrast enhancement during cardiac computed tomography angiography in newborns and infants.

INTRODUCTION: To investigate how changing the injection duration at cardiac computed tomography angiography (CCTA) affects contrast enhancement in newborns and infants. METHODS: Included were 142 newborns and infants with confirmed congenital heart disease who underwent CCTA between January 2015 and December 2018. In group 1 (n = 71 patients), the injection duration was 8 s; in group 2 (n = 71) it was 16 s. Our findings were assessed by one-to-one matching analysis to estimate the propensity score of each patient. We compare the CT number for the pulmonary artery (PA), ascending aorta (AAO), left superior vena cava (SVC), AAO and PA enhancement ratio, and the scores for visualization between the two groups. RESULTS: In group 1, median CT number and ranges was 345 (211-591) HU in the AAO, 324 (213-567) HU in the PA, and 62 (1-70) HU in the SVC. These values were 465 (308-669) HU, 467 (295-638) HU, and 234 (67-443) HU, respectively, in group 2 (p < 0.05). The median score for volume-rendering visualization on 3D images of the CCTA was 2 in group 1 and 3 in group 2; the score for visualization of the left SVC of the maximum intensity projection images was 2 in group 1 and 3 in group 2 (p < 0.05). The CT number for the AAO and PA enhancement ratio was 15.2 in group 1 and 9.2 in group 2 (p < 0.05). CONCLUSION: The 16-sec injection protocol yielded significantly higher CT numbers for the AAO, PA, and the SVC than the 8-sec injection protocol; the visualization scores were also significantly higher in group 2. IMPLICATIONS FOR PRACTICE: In newborns and infants, the longer injection time for CCTA yields stable and higher contrast enhancement at identical CM concentrations.

Simple Resistance Exercise helps Patients with Non-alcoholic Fatty Liver Disease.

To date, only limited evidence has supported the notion that resistance exercise positively impacts non-alcoholic fatty liver disease. We evaluated the effects of resistance exercise on the metabolic parameters of non-alcoholic fatty liver disease (NAFLD) in 53 patients who were assigned to either a group that performed push-ups and squats 3 times weekly for 12 weeks (exercise group; n=31) or a group that did not (control; n=22). Patients in the control group proceeded with regular physical activities under a restricted diet throughout the study. The effects of the exercise were compared between the 2 groups after 12 weeks. Fat-free mass and muscle mass significantly increased, whereas hepatic steatosis grade, mean insulin and ferritin levels, and the homeostasis model assessment-estimated insulin resistance index were significantly decreased in the exercise group. Compliance with the resistance exercise program did not significantly correlate with patient background characteristics such as age, sex, BMI and metabolic complications. These findings show that resistance exercise comprising squats and push-ups helps to improve the characteristics of metabolic syndrome in patients with non-alcoholic fatty liver disease.

Asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA) as an early predictor of survival in acute liver failure.

This study evaluated the usefulness of asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA scintigraphy) as an early predictor for prognosis of acute liver failure. Forty-eight patients with acute liver failure and without a past history of chronic liver disease were enrolled. Patients were divided into survival and non-survival groups by 28-day mortality. 99mTc-GSA scintigraphy to detect uptake ratio of the heart at 15 minutes to that at three minutes (HH15) and uptake ratio of the liver at 15 minutes to the liver plus the heart at 15 minutes (LHL15), and measurements of serum total bilirubin, hepatocyte growth factor and prothrombin time were performed immediately after the diagnosis of acute liver failure. Areas under the receiver operating characteristic curves were used to compare the prognostic ability of total bilirubin, hepatocyte growth factor, prothrombin time, HH15 ratio, LHL15 ratio and the model for end-stage liver disease score. Clinical characteristics of patients in the survival group (n=20) and in the non-survival group (n=28) were not significantly different. HH15 and LHL15 uptake ratios in the survival group were 0.670 and 0.875, and they were significantly lower and higher than those in the non-survival group, respectively. All patients with LHL15 <0.760 died, and the area under the receiver operating characteristic curve for LHL15 were significantly larger than the areas under the receiver operating characteristic curves of serum variables and model for end-stage liver disease score. In summary, in patients with acute liver failure without chronic liver disease, HH15 and LHL15 of 99mTc-GSA scintigraphy are more useful variables in predicting prognosis than serum variables and model for end-stage liver disease score.

Peroral video cholangioscopy to evaluate indeterminate bile duct lesions and preoperative mucosal cancerous extension: a prospective multicenter study.

BACKGROUND AND STUDY AIMS: Despite the development of peroral video cholangioscopy (PVCS), no prospective multicenter studies have been undertaken to investigate the diagnostic accuracy of PVCS in biliary tract diseases. Therefore, the aim of this study was to clarify the accuracy of PVCS in evaluating biliary tract lesions. PATIENTS AND METHODS: This study was a prospective multicenter study at five tertiary referral centers in Japan and included 87 eligible patients with biliary tract diseases who underwent PVCS. The study evaluated the ability of PVCS to diagnose indeterminate biliary tract diseases, detect mucosal cancerous extension preoperatively in extrahepatic bile duct cancers, and predict adverse events. RESULTS: The use of PVCS appearance alone correctly distinguished benign from malignant indeterminate biliary lesions in 92.1 % of patients whereas biopsy alone was accurate in 85.7 %. In extrahepatic bile duct cancer, mucosal cancer extended histologically at least 20 mm in 34.7 % (17/49) of patients. The accuracy rate of PVCS to evaluate the presence or absence of mucosal cancerous extension by endoscopic retrograde cholangiography (ERC) alone, ERC with PVCS, and ERC with PVCS + biopsy were 73.5 %, 83.7 %, and 92.9 %, respectively. Adverse events were seen in 6.9 % of PVCS patients, but no serious complications were observed. CONCLUSION: PVCS enhanced the accurate diagnosis of biliary tract lesions by providing excellent resolution in combination with biopsy.

Mechanism of oocyte maturation and ovulation and its application to seed production in the Japanese eel.

Reduction in eel resources and catches of glass eels as seedlings for aquaculture have been a serious concern in recent years in both Europe and East Asia. Thus, technical advancement to produce eel seeds for artificial cultivation is most desired. Fundamental information on oocyte maturation and ovulation and its application to artificial induction of sexual maturation are needed to produce good quality seeds of the Japanese eel. This review introduces hormonal mechanisms of cytoplasmic maturation (such as hydration, lipid coalescence, and clearing of the ooplasm) and the maturational competence (the ability to respond to maturation-inducing steroid) and nuclear maturation (germinal vesicle breakdown). In addition, previous and newly developed methods for induction of spawning have been described.

Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

BACKGROUND AND STUDY AIMS: Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. PATIENTS AND METHODS: The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. RESULTS: Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. CONCLUSIONS: Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention.

Fine needle aspiration using forward-viewing endoscopic ultrasonography.

BACKGROUND AND STUDY AIM: A prototype forward-viewing instrument has been developed for therapeutic endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA). We had the opportunity to use this forward-viewing echo endoscope and to study its clinical usefulness, mainly for diagnostic EUS-FNA. PATIENTS AND METHODS: The prototype forward-viewing echo endoscope was used for 15 months between November 2006 and March 2010, in a study group comprising 47 consecutive patients. Diagnostic EUS-FNA was done in 38 patients and the diagnostic accuracy of the forward-viewing device was compared with that from an oblique-viewing echo endoscope in reference patients who were matched by disease and puncture route. Therapeutic EUS was done in nine patients (pseudocyst drainage in six; celiac ganglia neurolysis, biliary drainage, and pancreatic duct drainage in one each). RESULTS: Diagnostic EUS-FNA provided a correct diagnosis in 97.4 % (37/38 patients), which was not significantly different from the 94.7 % (36/38) in the reference patients. Lesions considered difficult to access with an oblique-viewing scope, such as those located at the fornix, or the head of the pancreas, or associated with strictures, were easily punctured, as were those located at the body or tail of the pancreas or at the porta hepatis. Treatment was successful in all nine patients who underwent therapeutic EUS procedures. None of the 47 patients had any complications. CONCLUSIONS: A forward-viewing echo endoscope that allows target sites to be punctured more perpendicularly with minimal effort, can be used for diagnostic EUS-FNA and this may be advantageous, depending on the site of target lesions.

Intramembranous bone tissue response to biodegradable octacalcium phosphate implant.

Previous studies showed that synthetic octacalcium phosphate (OCP) enhances bone formation coupled with its own osteoclastic biodegradation more than non-biodegradable hydroxyapatite (HA), including sintered HA ceramic, when implanted in animal bone defects. The present study was designed to investigate whether synthetic OCP in granule form has biodegradable characteristics when implanted in the subperiosteal area of mouse calvaria in comparison with non-sintered stoichiometric HA, especially in relatively short periods after implantation. OCP crystals exhibited plate-like morphology, whereas HA crystals had a sphere-like structure. Both crystals had large pore volumes >75% in total, with micropores within the granules. Direct bonding of newly formed bone was discernible in HA until 35 days after implantation by element analysis for calcium and phosphorus. However, histomorphometric analysis demonstrated that bone formation was facilitated on OCP surfaces with greater alkaline phosphatase activity than on HA up to 21 days. The surfaces attacked by tartrate-resistant acid phosphatase positive osteoclast-like cells were significantly greater than those of HA. OCP became encapsulated and replaced with new bone with prolonged implantation periods up to 180 days. The results suggest that the enhanced bone formation in mouse calvaria could be associated with the biodegradable nature of OCP, and that OCP could be used in augmenting intramembranous bone volume.

Bone regeneration by synthetic octacalcium phosphate and its role in biological mineralization.

Octacalcium phosphate (Ca8H2(PO4)6 * 5H2O; OCP) has been advocated to be a precursor of biological apatite crystals in bone and tooth. Recent studies, using physical techniques, showed that OCP is present as a transient phase during biological apatite formation in human dentin, porcine enamel and murine bone. However, there is still a controversy regarding the chemical nature of the first mineral formed in the biominerals. A number of studies have demonstrated that synthetic OCP shows bone regenerative and biodegradable characteristics, rather than other calcium phosphate bone substitute materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HA) ceramic. It seems likely that synthetic OCP may be an alternative to autogenous bone graft. It is known that OCP contains alternative layers of water molecules and an apatite structure, and that the transition of OCP to HA is likely to be spontaneous and irreversible. The conversion process induces modification of local environment adjacent to OCP surface, including the changes in adsorption of serum proteins and concentration of calcium and inorganic phosphate ions. This article reviews the possible application to bone regeneration by synthetic OCP and the mechanism to enhance bone regeneration in relation to biological mineralization in bone and tooth.

Reactivity of hydroxybenzoic acids in the hydrogen-isotope exchange reaction.

The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritiated water vapor (HTO vapor) and 3-hydroxy-4-methoxybenzoic acid (and it's analog; 4-hydroxy-3-methoxybenzoic acid) were observed at 50 and 70 degrees C in a gas-solid system to reveal the reactivity of a functional group in an aromatic compound having two substituents in the aromatic ring. Further, it was shown that (a) the reactivity of the compounds used in this work follows the Hammett's rule, and (b) the reactivity of trisubstituted aromatic compound could be analyzed by applying the additive property of the Hammett's rule even if the compound contains a substituent at the ortho-position.

Comparative study on osteoconductivity by synthetic octacalcium phosphate and sintered hydroxyapatite in rabbit bone marrow.

Octacalcium phosphate (OCP) is thought to be a precursor of the mineral crystals in biological apatite. Synthetic OCP has been shown to be converted into an apatite structure when implanted in murine calvarial bone, to enhance bone regeneration more than synthetic hydroxyapatite (HA), and to degrade faster than biodegradable beta-tricalcium phosphate. This study was designed to investigate whether OCP implantation enhances the formation and resorption of new bone (remodeling) concomitant with OCP degradation when implanted intramedullary in a rabbit femur for 12 weeks, compared to sintered HA ceramic. Histological and histomorphometric analyses using undecalcified specimens showed that the area of bone apposition was significantly higher on OCP than on HA between 2 and 3 weeks, whereas it subsequently became smaller on OCP than on HA. The area attacked by multinucleated giant cells, including tartrate-resistant acid phosphatase (TRAP)-positive cells, was significantly higher for OCP than for HA at 8 weeks. Radiography revealed resorption of OCP but not of HA. The results disclose some osteoconductive characteristics of synthetic OCP in the bone marrow space: (1) enhancement of bone regeneration at the initial bone apposition stage and (2) stimulation of resorption of the newly formed bone coupled with OCP biodegradation mediated by TRAP-positive osteoclast-like cells. These results suggest that synthetic OCP would be a more useful bone substitute than HA in implant applications where rapid bone formation and concomitant implant resorption are important considerations.

Production and blood parameters of Holstein cows treated prepartum with sodium monensin or propylene glycol.

Forty-five multiparous Holstein cows were assigned to one of 3 treatments in a randomized complete block design. The objective was to evaluate the effects of sodium monensin (M) and propylene glycol (PPG) during the prepartum period on performance and metabolic parameters during the late dry and first 9 wk postpartum for cows receiving M postpartum. Treatments were: control (C), M in a controlled-release capsule to deliver 335 +/- 33 mg/d for approximately 100 d, and 300 mL/d of PPG drenched orally. Treatments started at 35 and 21 d prior to the expected date of calving for cows receiving M and PPG, respectively. To ensure that all treatments would be restricted to the prepartum period, C and PPG cows received a M controlled-release capsule in the first 24 h after calving. Prepartum propylene glycol administration increased concentrations of glucose and insulin, and decreased beta-hydroxybutyrate and nonesterified fatty acids in plasma prepartum. Milk production was similarly affected by treatments. However, prepartum M treated cows tended to produce more 3.5% fat-corrected milk compared with control, but similar to PPG. Milk fat content and yield tended to be greater for cows that received M prepartum than for C cows, while PPG cows were similar to M and C. Prepartum administration of M decreased milk protein content, but no effect was observed on protein yield.

Reductions in levels of bacterial superantigens/cannabinoids by plasma exchange in a patient with severe toxic shock syndrome.

Toxic shock syndrome is a rare but potentially fatal toxin-mediated febrile illness. We report a case of toxic shock syndrome complicated by life-threatening organ dysfunction with high toxin-1 and staphylococcus enterotoxin type A levels that were successfully reduced by early introduction of plasma exchanges. The report shows the time course of the concentrations of anandamide and 2-arachidonyl glyceride and confirms that early introduction of plasma exchange can result in a rapid reduction of circulating toxins and mediators in the treatment of life-threatening multiple organ dysfunction.

Endoscopic mucosal resection in the management of gastric carcinoid tumors.

BACKGROUND AND STUDY AIMS: Gastric carcinoid tumors are a rare disease. Previously, total gastrectomy was regarded as the treatment of choice. However, differences in biological malignancy have recently led to the increased use of endoscopic mucosal resection (EMR) for treatment. We studied the outcome of EMR in patients with gastric carcinoids who were treated at our hospital and discuss the indications for endoscopic treatment. PATIENTS AND METHODS: Between 1986 and 1999 we carried out gastric mucosal resection in five patients with gastric carcinoid tumors. The procedure used for EMR was either strip biopsy or endoscopic aspiration mucosectomy. RESULTS: The carcinoid tumors measured 10 mm or less in four of the five patients. Two patients had type A gastritis, and all had hypergastrinemia. There was no evidence of recurrence during follow-up (range 6 - 66 months; mean 32.6 months). CONCLUSION: EMR is useful in the management of type 1 gastric carcinoids as classified by Rindi (hypergastrinemia; tumor diameter of 10 mm or less).

[Persistent left-sided superior vena cava diagnosed after flow-directed pulmonary artery catheterization; report of a case].

We describe a case of persistent left-sided superior vena cava discovered after insertion of a pulmonary artery (PA) catheter. The diagnosis was suggested by chest X-ray after PA catheter placement and was subsequently confirmed by an echocardiograph. A 68-year-old man was admitted to our ICU because of septic shock induced by MRSA enterocolitis. In order to monitor the hemodynamic state of the patient, a PA catheter was inserted through the left subclavian vein after placement of a central venous and flexible double lumen catheters through the right internal jugular and subclavian veins, respectively. A chest X-ray showed the PA catheter passing along the left border of the heart. An echocardiograph showed the PA catheter passing through the coronary sinus into the pulmonary artery. Anesthesiologists and intensivists should be aware of the occurrence of left-sided superior vena cava in order not to mistake catheters placed in it as being in the arterial circulation or malpositioned outside of the venous circulation.

Simultaneous measurement of anandamide and 2-arachidonoylglycerol by polymyxin B-selective adsorption and subsequent high-performance liquid chromatography analysis: increase in endogenous cannabinoids in the sera of patients with endotoxic shock.

Anandamide (ANA) and 2-arachidonoylglycerol (2-AG), two endogenous cannabinoids, can be generated by activated macrophages and platelets, respectively, in the context of endotoxic shock, and are proposed to play a crucial role in the induction of the shock-related hypotension. Taking advantage of our recently discovered function of polymyxin B (PMB) binding to ANA and 2-AG, we developed a new method for measuring ANA and 2-AG by applying PMB-immobilized beads to selectively adsorb them in biological fluids, instead of organic solvent extraction. The eluate from beads can be directly fractionated by reverse-phase high-performance liquid chromatography (HPLC), and the fractionations corresponding to authentic ANA and 2-AG are collected and derivatized with fluorogenic reagent and subsequently quantified by HPLC with fluorometric detection. The calibration graphs of ANA and 2-AG were linear over a range of 1 to 500 pmol/ml. The limits of detection for ANA and 2-AG were 20 and 50 fmol, respectively. Intraassay precision was 2.24-4.25 and 3.47-5.44%, and interassay was 4.05-6.14 and 4.92-7.28% for ANA and 2-AG, respectively. Using this method, we first determined a 4-fold and 3-fold higher level of ANA and 2-AG, respectively, in the sera of patients with endotoxic shock than in normal serum. This finding should help in elucidating the role of the endogenous cannabinoids in the hypotension of human endotoxic shock. This method is rapid, sensitive, and reliable for simultaneously quantifying ANA and 2-AG in biological fluids, and has potential for clinical usage.