In situ electrochemical regeneration of active 1,4-NADH for enzymatic lactic acid formation via concerted functions on Pt-modified TiO2/Ti

Nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) are key cofactors serving as essential hydrogen acceptors and donors to facilitate energy and material conversions under mild conditions. We demonstrate direct electrochemical conversion to achieve highly efficient regeneration of enzymatically active 1,4-NADH using a Pt-modified TiO2 catalyst grown directly on a Ti mesh electrode (Pt-TOT). Spectral analyses revealed that defects formed by the inclusion of Pt species in the lattice of TiO2 play a critical role in the regeneration process. In particular, Pt-TOT containing approximately 3 atom% of Pt exhibited unprecedented efficiency in the electrochemical reduction of NAD+ at the lowest overpotential to date. This exceptional performance led to the production of active 1,4-NADH with a significantly high yield of 86 ± 3% at -0.6 V vs. Ag/AgCl (-0.06 V vs. RHE) and an even higher yield of 99.5 ± 0.4% at a slightly elevated negative potential of -0.8 V vs. Ag/AgCl (-0.2 V vs. RHE). Furthermore, the electrochemically generated NADH was directly applied in the enzymatic conversion of pyruvic acid to lactic acid using lactate dehydrogenase.

External validation of the HACOR score and ROX index for predicting treatment failure in patients with coronavirus disease 2019 pneumonia managed on high-flow nasal cannula therapy: a multicenter retrospective observational study in Japan

BACKGROUND

The HACOR score for predicting treatment failure includes vital signs and acid-base balance factors, whereas the ROX index only considers the respiratory rate, oxygen saturation, and fraction of inspired oxygen (FiO2). We aimed to externally validate the HACOR score and ROX index for predicting treatment failure in patients with coronavirus disease 2019 (COVID-19) on high-flow nasal cannula (HFNC) therapy in Japan.

METHODS

This retrospective, observational, multicenter study included patients, aged ≥ 18 years, diagnosed with COVID-19 and treated with HFNC therapy between January 16, 2020, and March 31, 2022. The HACOR score and ROX index were calculated at 2, 6, 12, 24, and 48 h after stating HFNC therapy. The primary outcome was treatment failure (requirement for intubation or occurrence of death within 7 days). We calculated the area under the receiver operating characteristic curve (AUROC) and assessed the diagnostic performance of these indicators. The 2-h time-point prediction was considered the primary analysis and that of other time-points as the secondary analysis. We also assessed 2-h time-point sensitivity and specificity using previously reported cutoff values (HACOR score > 5, ROX index < 2.85).

RESULTS

We analyzed 300 patients from 9 institutions (median age, 60 years; median SpO2/FiO2 ratio at the start of HFNC therapy, 121). Within 7 days of HFNC therapy, treatment failure occurred in 127 (42%) patients. The HACOR score and ROX index at the 2-h time-point exhibited AUROC discrimination values of 0.63 and 0.57 (P = 0.24), respectively. These values varied with temporal changes-0.58 and 0.62 at 6 h, 0.70 and 0.68 at 12 h, 0.68 and 0.69 at 24 h, and 0.75 and 0.75 at 48 h, respectively. The 2-h time-point sensitivity and specificity were 18% and 91% for the HACOR score, respectively, and 3% and 100% for the ROX index, respectively. Visual calibration assessment revealed well calibrated HACOR score, but not ROX index.

CONCLUSIONS

In COVID-19 patients receiving HFNC therapy in Japan, the predictive performance of the HACOR score and ROX index at the 2-h time-point may be inadequate. Furthermore, clinicians should be mindful of time-point scores owing to the variation of the models' predictive performance with the time-point. Trial registration UMIN (registration number: UMIN000050024, January 13, 2023).

Impact of intraoperative fluid management on postoperative complications in patients undergoing minimally invasive esophagectomy for esophageal cancer: a retrospective single-center study

BACKGROUND

Esophagectomy is a high-risk procedure that can involve serious postoperative complications. There has been an increase in the number of minimally invasive esophagectomies (MIEs) being performed. However, the relationship between intraoperative management and postoperative complications in MIE remains unclear.

METHODS

After the institutional review board approval, we enrolled 300 patients who underwent MIE at Tohoku University Hospital between April 2016 and March 2021. The relationships among patient characteristics, intraoperative and perioperative factors, and postoperative complications were retrospectively analyzed. The primary outcome was the relationship between intraoperative fluid volume and anastomotic leakage, and the secondary outcomes included the associations between other perioperative factors and postoperative complications.

RESULTS

Among 300 patients, 28 were excluded because of missing data; accordingly, 272 patients were included in the final analysis. The median [interquartile range] operative duration was 599 [545-682] minutes; total intraoperative infusion volume was 3,747 [3,038-4,399] mL; total infusion volume per body weight per hour was 5.48 [4.42-6.73] mL/kg/h; and fluid balance was + 2,648 [2,015-3,263] mL. The postoperative complications included anastomotic leakage in 68 (25%) patients, recurrent nerve palsy in 91 (33%) patients, pneumonia in 62 (23%) patients, cardiac arrhythmia in 13 (5%) patients, acute kidney injury in 5 (2%) patients, and heart failure in 5 (2%) patients. The Cochrane-Armitage trend test indicated significantly increased anastomotic leakage among patients with a relatively high total infusion volume (P = 0.0085). Moreover, anastomotic leakage was associated with male sex but not with peak serum lactate levels. Patients with a longer anesthesia duration or recurrent nerve palsy had a significantly higher incidence of postoperative pneumonia than those without. Further, the incidence of postoperative pneumonia was not associated with the operative duration, total infusion volume, or fluid balance. The operative duration and blood loss were related to the total infusion volume. Acute kidney injury was not associated with the total infusion volume or serum lactate levels.

CONCLUSIONS

Among patients who underwent MIE, the total infusion volume was positively correlated with the incidence of anastomotic leakage. Further, postoperative pneumonia was associated with recurrent nerve palsy but not total infusion volume or fluid balance.

Aortic valve replacement in a 41-year-old woman with uncorrected tetralogy of Fallot, pulmonary atresia, and major aortopulmonary collateral arteries: a case report

BACKGROUND

Tetralogy of Fallot (TOF) is a complex cyanotic congenital heart disease. As most patients with TOF undergo palliative or radical surgical repair during childhood, cardiac surgery under cardiopulmonary bypass (CPB) for adult survivors with unrepaired TOF is exceedingly rare.

CASE PRESENTATION

A 41-year-old woman with unrepaired TOF, pulmonary atresia (PA), and major aortopulmonary collateral arteries (MAPCAs) developed acute infectious endocarditis (IE). As vegetation gradually increased despite intravenous antibiotic administration, she was scheduled for urgent aortic valve replacement under CPB. Pulmonary blood flow was primarily provided by the MAPCAs originating from the descending aorta. Intra-aortic balloon occlusion for MAPCAs was performed to ensure a bloodless surgical field. Aortic valve replacement was successful.

CONCLUSION

An adult with uncorrected TOF developed acute IE and subsequently had successful cardiac surgery under CPB. Understanding TOF physiology with PA and MAPCAs, particularly pulmonary blood flow through MAPCAs, is crucial.

Intensive care unit mortality and cost-effectiveness associated with intensivist staffing: a Japanese nationwide observational study

BACKGROUND

Japan has four types of intensive care units (ICUs) that are divided into two categories according to the management fee charged per day: ICU management fees 1 and 2 (ICU1/2) (equivalent to high-intensity staffing) and 3 and 4 (ICU3/4) (equivalent to low-intensity staffing). Although ICU1/2 charges a higher rate than ICU3/4, no cost-effectiveness analysis has been performed for ICU1/2. This study evaluated the clinical outcomes and cost-effectiveness of ICU1/2 compared with those of ICU3/4.

METHODS

This retrospective observational study used a nationwide Japanese administrative database to identify patients admitted to ICUs between April 2020 and March 2021 and divided them into the ICU1/2 and ICU3/4 groups. The ICU mortality rates and in-hospital mortality rates were determined, and the incremental cost-effectiveness ratio (ICER) (Japanese Yen (JPY)/QALY), defined as the difference between quality-adjusted life year (QALY) and medical costs, was compared between ICU1/2 and ICU3/4. Data analysis was performed using the Chi-squared test; an ICER of < 5 million JPY/QALY was considered cost-effective.

RESULTS

The ICU1/2 group (n = 71,412; 60.7%) had lower ICU mortality rates (ICU 1/2: 2.6% vs. ICU 3/4: 4.3%, p < 0.001) and lower in-hospital mortality rates (ICU 1/2: 6.1% vs. ICU 3/4: 8.9%, p < 0.001) than the ICU3/4 group (n = 46,330; 39.3%). The average cost per patient of ICU1/2 and ICU3/4 was 2,249,270 ± 1,955,953 JPY and 1,682,546 ± 1,588,928 JPY, respectively, with a difference of 566,724. The ICER was 718,659 JPY/QALY, which was below the cost-effectiveness threshold.

CONCLUSIONS

ICU1/2 is associated with lower ICU patient mortality than ICU3/4. Treatments under ICU1/2 are more cost-effective than those under ICU3/4, with an ICER of < 5 million JPY/QALY.

Effectiveness of substantial shortening of the endotracheal tube for decreasing airway resistance and increasing tidal volume during pressure-controlled ventilation in pediatric patients: a prospective observational study

The endotracheal tubes (ETTs) used for children have a smaller inner diameter. Accordingly, the resistance across ETT (RETT) is higher. Theoretically, shortening the ETTs can decrease total airway resistance (Rtotal), because Rtotal is sum of RETT and patient's airway resistance. However, the effectiveness of ETT shortening for mechanical ventilation in the clinical setting has not been reported. We assessed the effectiveness of shortening a cuffed ETT for decreasing Rtotal, and increasing tidal volume (TV), and estimated the RETT/Rtotal ratio in children. In anesthetized children in a constant pressure-controlled ventilation setting, Rtotal and TV were measured with a pneumotachometer before and after shortening a cuffed ETT. In a laboratory experiment, the pressure gradient across the original length, shortened length, and the slip joint alone of the ETT were measured. We then determined the RETT/Rtotal ratio using the above results. The clinical study included 22 children. The median ETT percent shortening was 21.7%. Median Rtotal was decreased from 26 to 24 cmH2O/L/s, and median TV was increased by 6% after ETT shortening. The laboratory experiment showed that ETT length and the pressure gradient across ETT are linearly related under a certain flow rate, and approximately 40% of the pressure gradient across the ETT at its original length was generated by the slip joint. Median RETT/Rtotal ratio were calculated as 0.69. The effectiveness of ETT shortening on Rtotal and TV was very limited, because the resistance of the slip joint was very large.

Transvenous Radiofrequency Catheter Ablation for an Aldosterone-Producing Tumor of the Left Adrenal Gland: A First in Human Case Report

PURPOSE

To describe a novel technique of transvenous radiofrequency catheter ablation of an aldosterone-producing adenoma (APA) of the left adrenal gland using the GOS System (Japan Lifeline, Tokyo, Japan). Using the GOS system, a flexible radiofrequency tip catheter can be inserted into the adrenal central and tributary veins, the drainers for functional tumors.

MATERIALS AND METHODS

An APA at the left adrenal gland, which was diagnosed by segmental adrenal venous sampling following administration of 0.25 mg cosyntropin, was ablated using the GOS catheter inserted into adrenal tributary veins via a right femoral vein 7-Fr sheath. The effect of radiofrequency ablation on APA was assessed using the international consensus on surgical outcomes for unilateral primary aldosteronism (PA).

RESULTS

No device-related complications were observed. The patient was deeply sedated under blood pressure and heart rate control with continuous administration of β-blockers. Then, the tumor and surrounding adrenal gland were cauterized at 7000 J two times each in sequence. The output time was 7-11 min for each ablation and 80 min in total. For blood pressure and pulse rate control, esmolol hydrochloride and phentolamine mesylate were used. The contrast enhancement of APA disappeared on dynamic CT immediately after the procedure. PA was biochemically cured until 12 months after the procedure.

CONCLUSION

Using the radiofrequency device with the GOS catheter and system is a method for cauterizing adrenal tumors from blood vessels. This approach resulted in a marked reduction in aldosterone concentrations and a complete biochemical cure of PA over the observation period.

Association Between Intraoperative Landiolol Use and In-Hospital Mortality After Coronary Artery Bypass Grafting: A Nationwide Observational Study in Japan

BACKGROUND

Ischemic heart disease is a leading cause of death worldwide, and coronary artery bypass grafting (CABG) is a major treatment. Landiolol is an ultra-short-acting beta-antagonist known to prevent postoperative atrial fibrillation. However, the effectiveness of intraoperative landiolol on mortality remains unknown. This study aimed to evaluate the association between intraoperative landiolol use and the in-hospital mortality in patients undergoing CABG.

METHODS

To conduct this retrospective cohort study, we used data from the Japanese Diagnosis Procedure Combination inpatient database. All patients who underwent CABG during hospitalization between July 1, 2010, and March 31, 2020, were included. Patients who received intraoperative landiolol were defined as the landiolol group, whereas the other patients were defined as the control group. The primary outcome was in-hospital mortality. Propensity score matching was used to compare the landiolol and control groups.

RESULTS

In total, 118,506 patients were eligible for this study, including 25,219 (21%) in the landiolol group and 93,287 (79%) in the control group. One-to-one propensity score matching created 24,893 pairs. After propensity score matching, the in-hospital mortality was significantly lower in the landiolol group than that in the control group (3.7% vs 4.3%; odds ratio 0.85; 95% confidence interval 0.78 to 0.94; P = .010).

CONCLUSIONS

Intraoperative landiolol use was associated with decreased in-hospital mortality in patients undergoing CABG. Further randomized controlled trials are required to confirm these findings.

Quantification of muscle tone by using shear wave velocity during an anaesthetic induction: a prospective observational study

OBJECTIVES

The quantitative assessment of muscle stiffness or weakness is essential for medical care. Shear wave elastography is non-invasive ultrasound method and provides quantitative information on the elasticity of soft tissue. However, the universal velocity scale for quantification has not been developed. The aim of the study is to determine the shear wave velocities of abdominal muscle during anesthetic induction and to identify methods to cancel the effects of confounders for future development in the quantitative assessment of muscle tone using the universal scale.

METHODS

We enrolled 75 adult patients undergoing elective surgery with ASA-PS I - III in the period between December 2018 and March 2021. We measured and calculated the shear wave velocity (SWV) before and after opioid administration (i.e., the baseline at rest and opioid-induced rigidity condition), and after muscle relaxant administration (i.e., zero reference condition). The SWV value was adjusted for the subcutaneous fat thickness by our proposed corrections. The SWVs after the adjustment were compared among the values in baseline, rigidity, and relaxation using one-way repeated-measures ANOVA and post hoc Tukey-Kramer test. A p-value of < 0.05 was considered to be statistically significant. UMIN Clinical Trials Registry identifier UMIN000034692, registered on October 30, 2018.

RESULTS

The SWVs in the baseline, opioid-induced rigidity, and muscle relaxation conditions after the adjustment were 2.08 ± 0.48, 2.41 ± 0.60, and 1.79 ± 0.30 m/s, respectively (p < 0.001 at all comparisons).

CONCLUSION

The present study suggested that the SWV as reference was 1.79 m/s and that the SWVs at rest and opioid-induced rigidity were ~ 10% and ~ 30% increase from the reference, respectively. The SWV adjusted for the subcutaneous fat thickness may be scale points for the assessment of muscle tone.

Continuous visualization and validation of pain in critically ill patients using artificial intelligence: a retrospective observational study

Machine learning tools have demonstrated viability in visualizing pain accurately using vital sign data; however, it remains uncertain whether incorporating individual patient baselines could enhance accuracy. This study aimed to investigate improving the accuracy by incorporating deviations from baseline patient vital signs and the concurrence of the predicted artificial intelligence values with the probability of critical care pain observation tool (CPOT) ≥ 3 after fentanyl administration. The study included adult patients in intensive care who underwent multiple pain-related assessments. We employed a random forest model, utilizing arterial pressure, heart rate, respiratory rate, gender, age, and Richmond Agitation-Sedation Scale score as explanatory variables. Pain was measured as the probability of CPOT scores of ≥ 3, and subsequently adjusted based on each patient's baseline. The study included 10,299 patients with 117,190 CPOT assessments. Of these, 3.3% had CPOT scores of ≥ 3. The random forest model demonstrated strong accuracy with an area under the receiver operating characteristic curve of 0.903. Patients treated with fentanyl were grouped based on CPOT score improvement. Those with ≥ 1-h of improvement after fentanyl administration had a significantly lower pain index (P = 0.020). Therefore, incorporating deviations from baseline patient vital signs improved the accuracy of pain visualization using machine learning techniques.

Endotracheal tube, by the venturi effect, reduces the efficacy of increasing inlet pressure in improving pendelluft

In mechanically ventilated severe acute respiratory distress syndrome patients, spontaneous inspiratory effort generates more negative pressure in the dorsal lung than in the ventral lung. The airflow caused by this pressure difference is called pendelluft, which is a possible mechanisms of patient self-inflicted lung injury. This study aimed to use computer simulation to understand how the endotracheal tube and insufficient ventilatory support contribute to pendelluft. We established two models. In the invasive model, an endotracheal tube was connected to the tracheobronchial tree with 34 outlets grouped into six locations: the right and left upper, lower, and middle lobes. In the non-invasive model, the upper airway, including the glottis, was connected to the tracheobronchial tree. To recreate the inspiratory effort of acute respiratory distress syndrome patients, the lower lobe pressure was set at -13 cmH2O, while the upper and middle lobe pressure was set at -6.4 cmH2O. The inlet pressure was set from 10 to 30 cmH2O to recreate ventilatory support. Using the finite volume method, the total flow rates through each model and toward each lobe were calculated. The invasive model had half the total flow rate of the non-invasive model (1.92 L/s versus 3.73 L/s under 10 cmH2O, respectively). More pendelluft (gas flow into the model from the outlets) was observed in the invasive model than in the non-invasive model. The inlet pressure increase from 10 to 30 cmH2O decreased pendelluft by 11% and 29% in the invasive and non-invasive models, respectively. In the invasive model, a faster jet flowed from the tip of the endotracheal tube toward the lower lobes, consequently entraining gas from the upper and middle lobes. Increasing ventilatory support intensifies the jet from the endotracheal tube, causing a venturi effect at the bifurcation in the tracheobronchial tree. Clinically acceptable ventilatory support cannot completely prevent pendelluft.

Circulating Extracellular Vesicle Levels in Patients with Coronavirus Disease 2019 Coagulopathy: A Prospective Cohort Study

Coronavirus disease 2019 (COVID-19) is associated with coagulopathy. However, the underlying mechanisms are not completely understood. We evaluated the association between COVID-19 coagulopathy and extracellular vesicle (EV) levels. We hypothesized that several EV levels would be higher in COVID-19 coagulopathy patients than in non-coagulopathy patients. This prospective observational study was conducted in four tertiary care faculties in Japan. We enrolled 99 COVID-19 patients (48 with coagulopathy and 51 without coagulopathy) aged ≥20 years who required hospitalization, and 10 healthy volunteers; we divided the patients into coagulopathy and non-coagulopathy groups according to the D-dimer levels (≥1 μg/mL and <1 μg/mL, respectively). We used flow cytometry to measure the tissue-factor-bearing, endothelium-derived, platelet-derived, monocyte-derived, and neutrophil-derived EV levels in platelet-free plasma. The EV levels were compared between the two COVID-19 groups as well as among the coagulopathy patients, non-coagulopathy patients, and healthy volunteers. No significant difference was found in EV levels between the two groups. Meanwhile, the cluster of differentiation (CD) 41 + EV levels were significantly higher in COVID-19 coagulopathy patients than in healthy volunteers (549.90 [255.05-984.65] vs. 184.3 [150.1-254.1] counts/µL, p = 0.011). Therefore, CD41+ EVs might play an essential role in COVID-19 coagulopathy development.

Accuracy of Cardiac Output Measured by Fourth-Generation Flotrac and Lidcorapid, and Their Characteristics Regarding Systemic Vascular Resistance in Patients Undergoing Cardiac Surgery

OBJECTIVES

The clinical use of less-invasive devices that calculate the cardiac output from arterial pressure waveform is increasing. The authors aimed to evaluate the accuracy and characteristics of the systemic vascular resistance index (SVRI) of the cardiac index measured by 2 less-invasive devices, fourth-generation FloTrac (CI_FT) and LiDCOrapid (CI_LR), compared with the intermittent thermodilution technique, using a pulmonary artery catheter (CI_TD).

DESIGN

This was a prospective observational study.

SETTING

This study was conducted at a single university hospital.

PARTICIPANTS

Twenty-nine adult patients undergoing elective cardiac surgery.

INTERVENTIONS

Elective cardiac surgery was used as an intervention.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic parameters, CI_FT, CI_LR, and CI_TD, were measured after the induction of general anesthesia, at the start of cardiopulmonary bypass, after completion of weaning from cardiopulmonary bypass, 30 minutes after weaning, and at sternal closure (135 measurements in total). The CI_FT and CI_LR had moderate correlations with CI_TD (r = 0.62 and 0.58, respectively). Compared with CI_TD, CI_FT, and CI_LR had a bias of -0.73 and -0.61 L/min/m², limit of agreement of -2.14-to-0.68 L/min/m² and -2.42-to-1.20 L/min/m², and percentage error of 39.9% and 51.2%, respectively. Subgroup analysis for evaluating SVRI characteristics showed that the percentage errors of CI_FT and CI_LR were 33.9% and 54.5% in low SVRI (<1,200 dyne×s/cm⁵/m), 37.6% and 47.9% in moderate SVRI (1,200-1,800 dyne×s/cm⁵/m), 49.3% and 50.6% in high SVRI (>1,800 dyne·s/cm⁵/m²), respectively.

CONCLUSIONS

The accuracy of CI_FT or CI_LR was not clinically acceptable for cardiac surgery. Fourth-generation FloTrac was unreliable in high SVRI. LiDCOrapid was inaccurate across a broad range of SVRI, and minimally affected by SVRI.

Doxorubicin induces cardiomyocyte death owing to the accumulation of dysfunctional mitochondria by inhibiting the autophagy fusion process

Doxorubicin (Dox), an anthracycline antibiotic, is an anticancer drug that inhibits DNA replication and cellular metabolic processes in cancer cells with high proliferative potential. However, Dox causes severe side effects, including myocardial damage and heart failure, but the molecular mechanism underlying Dox-induced myocardial injury remains uncertain. In the present study, we evaluated the effects of Dox on the mitochondrial quality control system and regulation of mitochondrial respiration and autophagy in an in vitro rat myoblast H9c2 cell culture model using western blotting, immunohistochemistry, the Seahorse XF24 system, and flow cytometry. Our results showed that Dox did not impair the initiation of autophagic flux or the functions of lysosomes; however, Dox affected the mitochondrial quality control system, leading to a fission-dominant morphology and impaired regulation of mitochondrial respiration, thereby increasing oxidative stress and inhibited progression of autophagy, particularly the fusion of autophagosomes with lysosomes. This inhibition caused a significant decrease in the formation of autolysosomes and was responsible for the accumulation of dysfunctional mitochondria and subsequent increase in oxidative stress, eventually leading to increased myocardial cell death.

Postreperfusion Syndrome Presenting as Posttransplant Portal Hypertension due to Prolonged Elevation of Pulmonary Vascular Resistance and the Role of Nitroglycerin in Diagnosis and Treatment: A Case Report of Budd-Chiari Syndrome

Postreperfusion syndrome is one of the responsible mechanisms of portal hypertension in patients undergoing liver transplantation. And post-transplant portal hypertension causes graft dysfunction. Postreperfusion syndrome is characterized by a decrease in arterial pressure and cardiac output, and an increase in central venous pressure, pulmonary artery pressure, and pulmonary vascular resistance that occurs after the release of the portal vein clamp. Although early recovery from postreperfusion syndrome is desired, there is a little medication therapy such as the administration of calcium chloride, sodium bicarbonate, and beta-agonist for postreperfusion syndrome. We present a case of postreperfusion syndrome manifested as post-transplant portal hypertension and reversed after nitroglycerin administration. A 49-year-old Asian woman was scheduled for liver transplantation because of Budd-Chiari syndrome. After portal vein reperfusion, she experienced severe postreperfusion syndrome. Administration of ephedrine and calcium restored arterial pressure; however, pulmonary artery pressure, pulmonary vascular resistance, and central venous pressure elevations were sustained, causing right ventricular overload. This condition did not improve after hepatic artery reperfusion, and caused post-transplant portal hypertension. After nitroglycerin administration, pulmonary vascular resistance and central venous pressure decreased, mean arterial pressure increased, right heart contractility recovered, and portal hypertension disappeared. Hemodynamic improvement by nitroglycerin administration helped in diagnosing postreperfusion syndrome and avoiding unnecessary splenectomy. If portal vein pressure increases after liver transplantation, the change in hemodynamic parameters by nitroglycerin administration should be assessed, which will lead to accurate diagnosis and appropriate treatment. Furthermore, postreperfusion syndrome should be listed as a differential diagnosis of post-transplant portal hypertension.

Sevoflurane administration from extracorporeal membrane oxygenation via the AnaConDa device for a patient with COVID-19: a breakthrough solution for the shortage of intravenous anesthetics

One of the major issues encountered during the coronavirus disease 2019 (COVID-19) pandemic has been the shortage of intravenous anesthetics. Moreover, patients undergoing extracorporeal membrane oxygenation (ECMO) need large quantities of intravenous anesthetics for sedation. We report the case of a 52-year-old man who was admitted to our hospital due to acute respiratory distress syndrome by COVID-19 and treated with ECMO. As controlling sedation with intravenous anesthetics was challenging, we attempted to administer inhaled anesthetics via the gas flow of ECMO. We decreased the quantity of intravenous anesthetics and opioids. This method might help overcome the shortage of intravenous anesthetics.

Antiemetic effects of baclofen in a shrew model of postoperative nausea and vomiting: Whole-transcriptome analysis in the nucleus of the solitary tract

Aims

The molecular genetic mechanisms underlying postoperative nausea and vomiting (PONV) in the brain have not been fully elucidated. This study aimed to determine the changes in whole transcriptome in the nucleus of the solitary tract (NTS) in an animal model of PONV, to screen a drug candidate and to elucidate the molecular genetic mechanisms of PONV development.

Methods

Twenty‐one female musk shrews were assigned into three groups: the Surgery group (shrew PONV model, n = 9), the Sham group (n = 6), and the Naïve group (n = 6). In behavioral studies, the main outcome was the number of emetic episodes. In genetic experiments, changes in the transcriptome in the NTS were measured. In a separate study, 12 shrews were used to verify the candidate mechanism underlying PONV.

Results

A median of six emetic episodes occurred in both the Sham and Surgery groups. Whole‐transcriptome analysis indicated the inhibition of the GABA_B receptor‐mediated signaling pathway in the PONV model. Baclofen (GABA_B receptor agonist) administration eliminated emetic behaviors in the shrew PONV model.

Conclusions

Our findings suggest that the GABA_B receptor‐mediated signaling pathway is involved in emesis and that baclofen may be a novel therapeutic or prophylactic agent for PONV.

Evaluation of contrast-enhanced ultrasonography with Sonazoid® in visualization of local anesthetic distribution in rectus sheath block: a prospective, clinical study

PURPOSE

Clear visualization of ultrasound (US) images is crucial for successful US-guided nerve block. However, accurate determination of local anesthetic (LA) distribution from US images remains difficult. Sonazoid^®, which comprises perflubutane microbubbles, is used to diagnose hepatic and breast tumors. This study aimed to investigate the visibility of Sonazoid^® in perioperative US-guided nerve block.

METHODS

We performed rectus sheath block (RSB) in patients scheduled for laparoscopic abdominal surgery (n = 10). 10 mL of a mixture containing equal amounts of 0.75% ropivacaine and iohexol with the addition of Sonazoid^® diluted 100-fold was administered. We investigated the correlation and agreement between Sonazoid^® and iohexol distributions. The brightness of the solution and tissues was calculated: a grayscale value between 0 (dark) and 255 (bright) was measured in all pixels of the region of interest. Adverse events were also investigated.

RESULTS

Sonazoid^® was clearly visualized and distinguished from the surrounding tissues both during and after RSB. The spread of Sonazoid® and iohexol was significantly correlated (spearman's ρ = 0.53, p = 0.0004). Bland-Altman analyses revealed significant mean difference between two methods (15.6 mm; 95% confidence interval [CI]: 10.6, 20.6; standard deviation (SD) 15.65; p < 0.0001). Limits of agreement were - 14.94 to 46.24 mm. Sonazoid^® significantly increased the mean grayscale values at the posterior rectus sheath (93.7 vs. 201.9, p < 0.0001). There were no complications.

CONCLUSION

Sonazoid diluted 100-fold^® was clearly visualized real-time, and the enhancement was sustained and measurable after RSB. Sonazoid^® could potentially be used for the contrast agent of US-guided nerve block.

Successive perioperative management of laparoscopic liver resection in the reverse Trendelenburg position for a patient with Fontan physiology: a case report

BACKGROUND

Laparoscopic surgery for a patient with Fontan physiology is challenging because pneumoperitoneum and positive pressure ventilation could decrease venous return and the accumulated partial pressure of arterial carbon dioxide (PaCO₂) could increase pulmonary vascular resistance, which might lead to disruption of the hemodynamics.

CASE PRESENTATION

A 25-year-old man with Fontan physiology was scheduled to undergo laparoscopic liver resection for Fontan-associated liver disease (FALD) with noninvasive monitoring of cardiac output (CO) by transpulmonary thermodilution in addition to transesophageal echocardiography. The abdominal air pressure was maintained low, and we planned to switch to open abdominal surgery promptly if hemodynamic instability became apparent because of the accumulated PaCO₂ or postural change. Consequently, the pneumoperitoneum had limited influence on circulatory dynamics, but central venous pressure significantly decreased with postural change to the reverse Trendelenburg position. Laparoscopic liver resection for FALD was performed successfully with no significant changes in CO and central venous saturation.

CONCLUSIONS

With strict circulation management, laparoscopic surgery for a patient with Fontan physiology can be performed safely. Comprehensive hemodynamic assessment by noninvasive transpulmonary thermodilution can provide valuable information to determine the time for shift to open abdominal surgery.

Crucial involvement of catecholamine neurotransmission in postoperative nausea and vomiting: Whole-transcriptome profiling in the rat nucleus of the solitary tract

The genetic mechanisms of postoperative nausea and vomiting (PONV) and the involvement of the catecholamine system in the brain have not been elucidated. Eating kaolin clay as a type of pica has been examined as an alternative behavior to emesis. Here, we evaluated changes in whole-transcriptome analysis in the nucleus of the solitary tract (NTS) in a rat pica model as a surrogate behavior of PONV to elucidate the molecular genetic mechanisms of the development of PONV and the involvement of the catecholamine system in the NTS. First, kaolin pica behaviors were investigated in 71 female Wistar rats following isoflurane anesthesia, surgical insult or morphine administration. Multiple linear regression analysis showed that 3 mg/kg morphine increased kaolin intake by 2.8 g (P = 0.0002). Next, total RNA and protein were extracted from the dissected NTS, and whole-transcriptome sequencing (RNA-seq) was performed to identify PONV-associated genes and to verify the involvement of the catecholamine system. The gene expression levels of tyrosine hydroxylase and dopamine beta-hydroxylase in the catecholamine biosynthesis pathway decreased significantly in the PONV model. Release of noradrenaline, a catecholamine pathway end product, may have increased at the synaptic terminal of the NTS neuron after pica behavior. Systematic administration of α2 adrenergic receptor agonists after surgery reduced kaolin intake from 3.2 g (control) to 1.0 g (P = 0.0014). These results indicated that catecholamine neurotransmission was involved in the development of PONV in the NTS.

Spurious electroencephalographic activity due to pulsation artifact in the depth of anesthesia monitor

Background

The depth of anesthesia (DOA) is estimated based on the anesthesia-induced electroencephalogram (EEG) changes. However, the surgical environment, as well as the patient him/herself, generates electrical interferences that cause EEG waveform distortion.

Case presentation

A 52-year-old patient required general anesthesia due to the right femur necrotizing fasciitis. He had no history of epilepsy or head injury. His cardiovascular status was stable without arrhythmia under propofol and remifentanil anesthesia. The DOA was evaluated with Root® with SedLine® Brain Function Monitoring (Masimo Inc, Irvine, CA). The EEG showed a rhythmic, heart rate time-locked pulsation artifact, which diminished after electrode repositioning. Offline analysis revealed that the pulse wave-like interference in EEG was observed at the heart rate frequency.

Conclusions

We experienced an anesthesia case that involves a pulsation artifact generated by the superficial temporal artery contaminating the EEG signal. Numerous clinical conditions, including pulsation artifact, disturb anesthesia EEG.

Semi-automated tracking of pain in critical care patients using artificial intelligence: a retrospective observational study

Monitoring the pain intensity in critically ill patients is crucial because intense pain can cause adverse events, including poor survival rates; however, continuous pain evaluation is difficult. Vital signs have traditionally been considered ineffective in pain assessment; nevertheless, the use of machine learning may automate pain assessment using vital signs. This retrospective observational study was performed at a university hospital in Sendai, Japan. Objective pain assessments were performed in eligible patients using the Critical-Care Pain Observation Tool (CPOT). Three machine-learning methods—random forest (RF), support vector machine (SVM), and logistic regression (LR)—were employed to predict pain using parameters, such as vital signs, age group, and sedation levels. Prediction accuracy was calculated as the harmonic mean of sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). Furthermore, 117,190 CPOT assessments were performed in 11,507 eligible patients (median age: 65 years; 58.0% males). We found that pain prediction was possible with all three machine-learning methods. RF demonstrated the highest AUROC for the test data (RF: 0.853, SVM: 0.823, and LR: 0.787). With this method, pain can be objectively, continuously, and semi-automatically evaluated in critically ill patients.

Nociceptive Sensitization by Activation of Protease-Activated Receptor 2 in a Rat Model of Incisional Pain

Postoperative pain and consequent inflammatory responses after tissue incision adversely affects many surgical patients due to complicated mechanisms. In this study, we examined whether activation of protease-activated receptor 2 (PAR-2), which is stimulated by tryptase from mast cells, elicits nociception and whether the PAR-2 antagonist could reduce incisional nociceptive responses in vivo and in vitro. The effects of a selective PAR-2 antagonist, N3-methylbutyryl-N-6-aminohexanoyl-piperazine (ENMD-1068), pretreatment on pain behaviors were assessed after plantar incision in rats. The effects of a PAR-2 agonist, SLIGRL-NH₂, on nociception was assessed after the injection into the hind paw. Furthermore, the responses of C-mechanosensitive nociceptors to the PAR-2 agonist were observed using an in vitro skin–nerve preparation as well. Intraplantar injection of SLIGRL-NH₂ elicited spontaneous nociceptive behavior and hyperalgesia. Local administration of ENMD-1068 suppressed guarding behaviors, mechanical and heat hyperalgesia only within the first few hours after incision. SLIGRL-NH₂ caused ongoing activity in 47% of C-mechanonociceptors in vitro. This study suggests that PAR-2 may support early nociception after incision by direct or indirect sensitization of C-fibers in rats. Moreover, PAR-2 may play a regulatory role in the early period of postoperative pain together with other co-factors to that contribute to postoperative pain.

Bicarbonate in Arteries Measured Preoperatively for Cadaveric Single-lung Transplantation is Related to Intraoperative Extra-Corporeal Membrane Oxygenation Use: A Retrospective Preliminary Study

Background

There are no known predictors of extracorporeal membrane oxygenation (ECMO) induction for single lung transplantation.

Objective

The purpose of the present study was to clarify the relationship between variables and ECMO requirements in single lung transplantation.

Methods

This study included adult patients who underwent cadaveric single lung transplantation between 2010 and 2019. After general anesthesia, the transplanted lungs were ventilated in all cases. The analysis included 38 patients in the ECMO required (RQ) group and 12 patients in the ECMO non-required (FR) group. Comparisons were made between the two groups for data affecting ECMO implementation, and data that were significantly different were subjected to multivariate analysis.

Results

Prior to anesthesia, the bicarbonate (HCO3-) value of the FR group was lower than that of the RQ group (24.6±2.7 vs. 29.7±5.3 mmol/L, p=0.005). Multivariate analysis showed that the cut-off bicarbonate value was 29.6. The area under the receiver operating characteristic curve (AUROC) of the model was 0.869 (R2: 0.331), with a sensitivity of 79% and a specificity of 88%. The odds ratio was 1.63 for every unit increase in the bicarbonate value (95%CI: 1.11-2.39, p<0.001). Further, the FR group had higher arterial blood pressure (mean: 79.0±11.5 vs. 68.9±8.3 mmHg, p=0.030), less blood loss (432±385 vs. 1,623±1,997 g, p<0.001), shorter operation time (417±44 vs. 543±111 min, p<0.001), and shorter ICU stay (11±9 vs. 25±38 days, p=0.039).

Conclusion

Preoperative evaluation of bicarbonate could predict the need for ECMO for single lung transplantation.

Effects of magnesium sulfate administration in attenuating chronic postsurgical pain in rats

Chronic postsurgical pain (CPSP) is a serious issue for many postoperative patients. Though there are numerous treatment options for the prevention of CPSP, none of them is optimal as the mechanisms of the transition from acute to chronic postoperative pain have not been elucidated. Ketamine and opioids have been administered for chronic postoperative pain treatment but induce severe adverse reactions and/or physical dependency. Here, we examined whether pre-administration of the nonselective N-methyl-d-aspartate (NMDA) receptor antagonist magnesium sulfate attenuates CPSP behavior and alters the expression of glutamate ionotropic receptor NMDA type subunit 1a (Grin1 mRNA) in a rat skin/muscle incision and retraction (SMIR) model. We assessed the effects of a single subcutaneous magnesium sulfate injection on nociceptive behaviors including guarding pain, mechanical hyperalgesia, and heat hypersensitivity in rats after SMIR surgery. We used reverse transcription-quantitative PCR (RT-qPCR) to evaluate Grin1 mRNA expression in the dorsal horn of the spinal cord on postoperative day 14. Compared with the vehicle, magnesium sulfate administration before SMIR surgery reduced mechanical hyperalgesia for 17 d Grin1 gene expression was significantly higher on the ipsilateral side than the contralateral side (P = 0.001) on postoperative day 14. The magnesium sulfate injection prevented Grin1 mRNA upregulation in the spinal cord dorsal horn. A single magnesium sulfate injection mitigated SMIR-induced mechanical hyperalgesia possibly by modulating Grin1 expression. Preoperative magnesium sulfate administration could prove to be a simple and safe CPSP treatment.

Management of cesarean section in a patient with Fontan circulation: a case report of dramatic reduction of maternal oxygen consumption after delivery

Background

The anesthetic management of cesarean sections in Fontan-palliated parturients requires strict hemodynamic control. However, patient management with central venous oxygen saturation (ScvO₂) and oxygen consumption (VO₂) has never been reported.

Case presentation

A 30-year-old woman, who had received a total cavopulmonary connection for tricuspid atresia, was planned to undergo cesarean section at 38 weeks’ gestation. During combined spinal-epidural anesthesia, ScvO₂ in addition to arterial pressure-based cardiac output (APCO) and central venous pressure (CVP) was monitored, and the change of VO₂ was evaluated. After delivery, her APCO was almost unchanged. However, her ScvO₂ increased dramatically from 42.1 to 67.3% and her CVP increased from 9 to 11 mm Hg. The calculated mean maternal VO₂ changed from 443 to 295 mL/min.

Conclusions

In a cesarean section for a Fontan-palliated parturient, ScvO₂ dramatically increased and maternal VO₂ decreased by more than 25% after delivery.

Long non-coding RNA MIR4300HG polymorphisms are associated with postoperative nausea and vomiting: a genome-wide association study

Background

Genetic factors such as single-nucleotide polymorphisms (SNPs) play a key role in the development of postoperative nausea and vomiting (PONV). However, previous findings are not widely applicable to different populations because of population-specific genetic variation. We developed a Japanese-specific DNA microarray for high-throughput genotyping. The aim of the current study was to identify SNPs associated with PONV on a genome-wide scale using this microarray in a sample of Japanese surgical patients.

Methods

Associations between 659,636 SNPs and the incidence of PONV 24 h after surgery in a limited sample of 24 female patients were assessed using the microarray. After imputation of genotypes at 24,330,529 SNPs, 78 SNPs were found to be associated with the incidence of PONV. We chose 4 of the 78 SNPs to focus on by in silico functional annotation. Finally, we genotyped these 4 candidate SNPs in 255 patients using real-time PCR to verify association with the incidence of PONV.

Results

The T > C variant of rs11232965 in the long non-coding RNA MIR4300HG was significantly associated with reduced incidence of PONV among genotypes and between alleles (p = 0.01 and 0.007).

Conclusions

We identified a novel SNP (rs11232965) in the long non-coding RNA MIR4300HG that is associated with PONV. The rs11232965-SNP variant (T > C) is protective against the incidence of PONV.

Trial registration

This study was registered at the UMIN Clinical Trials Registry (Identifier: UMIN000022903, date of registration: June 27, 2016, retrospectively registered.

DEVELOPMENT OF A JAPANESE INFANT HEAD-CHEST PHANTOM AND INVESTIGATION OF THE CURRENT STATUS OF INFANT HEAD CT EXAMINATIONS IN JAPAN

The aim of this study was to develop a head-chest phantom that could mimic the physique of a Japanese 0.5-year-old child and to investigate the current status of exposure dose in infant head computed tomography examinations in Japan. The phantom was produced by machine processing, and radiophotoluminescence glass dosemeters were installed in the phantom for dose measurement. Organ doses were measured for seven different head scan protocols routinely used in three hospitals. In this study, the average dose of the brain and lens within the scan region was equivalent to that measured using infant phantoms in previous studies. In contrast, the doses of both salivary glands and thyroid glands adjacent to the scan region were 1.4-1.8 times higher than those in previous studies. Expansion of the scan area accompanied by a transition of the scan mode from non-helical to helical may have resulted in the differences in organ doses.

α 1-Adrenergic Receptor Blockade by Prazosin Synergistically Stabilizes Rat Peritoneal Mast Cells

BACKGROUND

Adrenaline quickly inhibits the release of histamine from mast cells. Besides β 2-adrenergic receptors, several in vitro studies also indicate the involvement of α-adrenergic receptors in the process of exocytosis. Since exocytosis in mast cells can be detected electrophysiologically by the changes in the membrane capacitance (Cm), its continuous monitoring in the presence of drugs would determine their mast cell-stabilizing properties.

METHODS

Employing the whole-cell patch-clamp technique in rat peritoneal mast cells, we examined the effects of adrenaline on the degranulation of mast cells and the increase in the Cm during exocytosis. We also examined the degranulation of mast cells in the presence or absence of α-adrenergic receptor agonists or antagonists.

RESULTS

Adrenaline dose-dependently suppressed the GTP-γ-S-induced increase in the Cm and inhibited the degranulation from mast cells, which was almost completely erased in the presence of butoxamine, a β 2-adrenergic receptor antagonist. Among α-adrenergic receptor agonists or antagonists, high-dose prazosin, a selective α 1-adrenergic receptor antagonist, significantly reduced the ratio of degranulating mast cells and suppressed the increase in the Cm. Additionally, prazosin augmented the inhibitory effects of adrenaline on the degranulation of mast cells.

CONCLUSIONS

This study provided electrophysiological evidence for the first time that adrenaline dose-dependently inhibited the process of exocytosis, confirming its usefulness as a potent mast cell stabilizer. The pharmacological blockade of α 1-adrenergic receptor by prazosin synergistically potentiated such mast cell-stabilizing property of adrenaline, which is primarily mediated by β 2-adrenergic receptors.

Successful management of an infant with hypertensive heart failure associated with Wilms' tumor: a case report

Background

Wilms’ tumor with hyperreninemia may result in critical cardiovascular decompensation. We report a case of severe hypertensive heart failure followed by tumor resection in a 3-month-old infant with Wilms’ tumor.

Case presentation

A 3-month-old girl was admitted to the intensive care unit for Wilms’ tumor with hypertension and hypoxia. Her systolic blood pressure was 110 mmHg, and her SpO₂ was 92%. She presented with severe hypertensive heart failure and received mechanical ventilation and antihypertensive therapy for hypertension and heart failure. An alpha 2-adrenergic receptor agonist was used for sedation as part of her antihypertensive therapy. On hospital day 16, nephrectomy with tumor resection was performed under general anesthesia. Her systolic blood pressure did not vary more than 20 mmHg during surgery due to appropriate preoperative management. Hemodynamic collapse did not occur.

Conclusions

The highlight of this case report is the successful management of an infant with Wilms’ tumor, particularly with respect to preoperative hemodynamic control and sedation.

SHAPE ESTIMATION OF BOWTIE FILTERS BASED ON THE LUMINESCENCE FROM POLYETHYLENE TEREPHTHALATE RESIN BY X-RAY IRRADIATION

In this study, we devised a novel method estimating the bowtie filter shapes by imaging luminescence from a polyethylene terephthalate (PET) resin with X-ray irradiation in a computed tomography (CT) scanner. The luminescence distribution of the PET resin corresponding to the thickness of bowtie filter was imaged using a charge-coupled device camera. On the assumption that the material of bowtie filter is aluminium (Al), the shape of bowtie filters was estimated from the correlation between Al attenuation curves and the angular-dependent luminance attenuation profiles according to the thickness of bowtie filters. Dose simulations based on the estimated bowtie filter shapes were performed using head and body PMMA phantoms with 16 and 32 cm in diameter. The simulated values of head and body weighted CT dose index (CTDIw) based on bowtie filter shape by the luminescence imaging method agreed within ~9% with the measured values by a dosemeter.

Perioperative anesthetic management for cesarean delivery of severe Wilson’s disease with liver failure: a case report

Background

Wilson’s disease is a rare autosomal recessive disorder affecting copper metabolism, which presents liver and brain dysfunction caused by abnormal copper accumulation. We report a patient who showed exacerbation of liver failure during pregnancy.

Case presentation

A 24-year-old woman with Wilson’s disease was scheduled for emergency cesarean delivery at 30 weeks of gestation. The patient exhibited severe coagulopathy and prominent body weight gain (+ 30 kg) caused by systemic edema and ascites. We decided to perform emergency cesarean delivery under general anesthesia. We used platelet concentrates, cryoprecipitate, and fibrinogen concentrate. Intraoperative hemorrhage was well controlled. On the 15th postpartum day, weight was reduced by 20 kg and liver function had improved. She and her baby were discharged without complications.

Conclusions

The appropriate continued treatment of Wilson’s disease and supplementation of coagulation factors and/or platelets when indicated greatly increase the likelihood of a successful pregnancy, even in patients with liver failure exacerbation.

Delayed Rectifier K+-Channel Is a Novel Therapeutic Target for Interstitial Renal Fibrosis in Rats with Unilateral Ureteral Obstruction

BACKGROUND

Delayed rectifier K+-channel, Kv1.3, is most predominantly expressed in T-lymphocytes and macrophages. In such leukocytes, Kv1.3-channels play pivotal roles in the activation and proliferation of cells, promoting cellular immunity. Since leukocyte-derived cytokines stimulate fibroblasts to produce collagen fibers in inflamed kidneys, Kv1.3-channels expressed in leukocytes would contribute to the progression of tubulointerstitial renal fibrosis.

METHODS

Male Sprague-Dawley rats that underwent unilateral ureteral obstruction (UUO) were used at 1, 2, or 3 weeks after the operation. We examined the histological features of the kidneys and the leukocyte expression of Kv1.3-channels. We also examined the therapeutic effects of a selective channel inhibitor, margatoxin, on the progression of renal fibrosis and the proliferation of leukocytes within the cortical interstitium.

RESULTS

In rat kidneys with UUO, progression of renal fibrosis and the infiltration of leukocytes became most prominent at 3 weeks after the operation, when Kv1.3-channels were overexpressed in proliferating leukocytes. In the cortical interstitium of margatoxin-treated UUO rat kidneys, immunohistochemistry revealed reduced expression of fibrosis markers. Additionally, margatoxin significantly decreased the numbers of leukocytes and suppressed their proliferation.

CONCLUSIONS

This study clearly demonstrated that the numbers of T-lymphocytes and macrophages were markedly increased in UUO rat kidneys with longer postobstructive days. The overexpression of Kv1.3-channels in leukocytes was thought to be responsible for the proliferation of these cells and the progression of renal fibrosis. This study strongly suggested the therapeutic usefulness of targeting lymphocyte Kv1.3-channels in the treatment of renal fibrosis.

Increase in circulating ACE-positive endothelial microparticles during acute lung injury

Circulating endothelial microparticles (EMPs) are considered to be markers of endothelial injury, and lung microvascular endothelial cells express higher levels of angiotensin-converting enzyme (ACE). The aim of this study is to examine whether the number of ACE⁺ microvascular EMPs could be a prognostic marker for the development of acute respiratory distress syndrome (ARDS) in septic patients.The numbers of EMPs and ACE⁺ EMPs in the culture supernatant from human microvascular endothelial cells, as well as in the blood of mouse lung injury models and septic patients (n=82), were examined using flow cytometry.ACE⁺ EMPs in the culture supernatant from pulmonary microvascular endothelial cells increased after exposure to an inflammatory stimulus. In the mouse lung injury models, the circulating ACE⁺ EMPs and ACE⁺ EMP/EMP ratio were higher than in the controls (p<0.001). The ACE⁺ EMP/EMP ratio was correlated with the wet/dry lung ratio (r_s=0.775, p<0.001). The circulating ACE⁺ EMPs and ACE⁺ EMP/EMP ratio on admission were significantly increased in septic patients who developed ARDS compared with septic patients who did not (p<0.001).Therefore, circulating ACE⁺ EMPs may be a prognostic marker for the development of ARDS in the septic patients.

HIGH BACKGROUND AREA FOR RADIATION EDUCATION

This paper describes our trial experience of the use of high radiation area for radiation education. We used environmental samples collected from the high radiation area in Fukushima prefecture and India, for the practice of radiation measurement and health risk assessment in Nagasaki University Medical School. We also carried out the field monitoring seminar for students in the existing exposure areas in Tottori prefecture and the Yamakiya observatory in Fukushima. Although the evaluation of educational effectiveness is still underway, both types of education appeared attractive for the students mostly due to the exposure from natural environment in our real life which was not achieved by using an artificial radiation source in a classroom.

Second-Generation Histamine H1 Receptor Antagonists Suppress Delayed Rectifier K+-Channel Currents in Murine Thymocytes

BACKGROUND/AIMS

Voltage-dependent potassium channels (Kv1.3) are predominantly expressed in lymphocyte plasma membranes. These channels are critical for the activation and proliferation of lymphocytes. Since second-generation antihistamines are lipophilic and exert immunomodulatory effects, they are thought to affect the lymphocyte Kv1.3-channel currents.

METHODS

Using the patch-clamp whole-cell recording technique in murine thymocytes, we tested the effects of second-generation antihistamines, such as cetirizine, fexofenadine, azelastine, and terfenadine, on the channel currents and the membrane capacitance.

RESULTS

These drugs suppressed the peak and the pulse-end currents of the channels, although the effects of azelastine and terfenadine on the peak currents were more marked than those of cetirizine and fexofenadine. Both azelastine and terfenadine significantly lowered the membrane capacitance. Since these drugs did not affect the process of endocytosis in lymphocytes, they were thought to have interacted directly with the plasma membranes.

CONCLUSIONS

Our study revealed for the first time that second-generation antihistamines, including cetirizine, fexofenadine, azelastine, and terfenadine, exert suppressive effects on lymphocyte Kv1.3-channels. The efficacy of these drugs may be related to their immunomodulatory mechanisms that reduce the synthesis of inflammatory cytokine.

The human central nervous system discharges carbon dioxide and lactic acid into the cerebrospinal fluid

BACKGROUND

The central nervous system was previously thought to draw oxygen and nutrition from the arteries and discharge carbon dioxide and other metabolic wastes into the venous system. At present, the functional role of cerebrospinal fluid in brain metabolism is not fully known.

METHODS

In this prospective observational study, we performed gas analysis on venous blood and cerebrospinal fluid simultaneously acquired from 16 consecutive preoperative patients without any known neurological disorders.

RESULTS

The carbon dioxide partial pressure (pCO₂) (p < 0.0001) and lactic acid level (p < 0.001) in the cerebrospinal fluid were significantly higher than those in the peripheral venous blood, suggesting that a considerable proportion of metabolic carbon dioxide and lactic acid is discharged from the central nervous system into the cerebrospinal fluid. The oxygen partial pressure (pO₂) was much higher in the cerebrospinal fluid than in the venous blood, corroborating the conventional theory of cerebrospinal fluid circulatory dynamics. The pCO₂ of the cerebrospinal fluid showed a strong negative correlation with age (R = - 0.65, p = 0.0065), but the other studied variables did not show significant correlation with age.

CONCLUSION

Carbon dioxide and lactic acid are discharged into the circulating cerebrospinal fluid, as well as into the venules. The level of carbon dioxide in the cerebrospinal fluid significantly decreased with age.

Aberrant Collagen Cross-linking in Human Oral Squamous Cell Carcinoma

Tumor progression is a complex process involving extracellular matrix (ECM) remodeling and stiffening. However, the mechanisms that govern these processes and their roles in tumor progression are still poorly understood. In this study, we performed bioinformatics, immunohistochemical, and biochemical analyses to examine if collagen cross-linking is associated with tumor stage and regional lymph node metastasis (RLNM) in oral squamous cell carcinoma (OSCC). We found that the genes encoding key enzymes for cross-linking are frequently overexpressed in oral, head, and neck cancers. Specifically, the enzymes lysyl hydroxylase 2 (LH2) or lysyl oxidase (LOX) and LOX-like 2 (LOXL2) were significantly upregulated in late-stage tumors and associated with poor patient prognosis. The protein levels of these enzymes in the primary human OSCC were also significantly increased in late-stage tumors and markedly elevated in the RLNM-positive tumors. Notably, while overall LOX/LOXL2-catalyzed collagen cross-links were enriched in late-stage and RLNM-positive tumors, LH2-mediated stable cross-links were significantly increased. To our knowledge, this is the first study to investigate the association of collagen cross-linking and expression of key enzymes regulating this process with OSCC stage. The data indicate a critical role for collagen cross-linking in OSCC tumor progression and metastasis, which may provide insights into development of novel therapeutic strategies to prevent OSCC progression.