Halogenated Cyclic Monoterpenoids with Anti-Biofouling Activity from the Okinawan Red Marine Algae Portieria Hornemannii

The red algal genus Portieria is a prolific producer of halogenated monoterpenoids. In this study, we isolated and characterised monoterpenoids from the Okinawan red algae Portieria hornemannii. A new polyhalogenated cyclic monoterpenoid, 2(R)-chloro-1,6(S)-dibromo-3(8)(Z)-ochtoden-4(R)-ol (1), along with three known monoterpenoids, (2R,3(8)E,4S,6R)-6-bromo-2-chloro-1,4-oxido-3(8)-ochtodene (2), 1-bromo-2-chloroochtoda-3(8),5-dien-4-one (3), and 2-chloro-1-hydroxyochtoda-3(8),5-dien-4-one (4) were isolated from the methanol extract of three populations of P. hornemannii. These compounds were characterised using a combination of spectroscopic methods and chemical synthesis, and the absolute stereochemistry of compounds 1 and 2 was determined. In addition, all isolated compounds were screened for their anti-biofouling activity against the mussel Mytilus galloprovincialis, and 1 exhibited strong activity. Therefore, halogenated monoterpenoids have the potential to be used as natural anti-biofouling drugs.

Divergent Nine-Step Syntheses of Perhydrohistrionicotoxin Analogs and Their Inhibition Activity Toward Chicken α4β2-Neuronal Nicotinic Acetylcholine Receptors

Histrionicotoxin (HTX) alkaloids, which are isolated from Colombian poison dart frogs, are analgesic neurotoxins that modulate nicotinic acetylcholine receptors (nAChRs) as antagonists. Perhydrohistrionicotoxin (pHTX) is the potent synthetic analogue of HTX and possesses a 1-azaspiro[5.5]undecane skeleton common to the HTX family. Here, we show for the first time the divergent nine-step synthesis of pHTX and its three stereoisomers from the known aldehyde through a one-step construction of the 1-azaspiro[5.5]undecane framework from a linear amino ynone substrate. Surprisingly, some pHTX diastereomers exhibited antagonistic activities on the chicken α4β2-neuronal nAChRs that were more potent than pHTX.

Establishment of "Ring-Size-Divergent" Synthetic Strategy: Divergent Synthesis, Stereochemical Assignments, and Biological Activity Studies of Nerolidol-Type Sesquiterpenoids and Feroniellins

Biomimetic epoxide-opening cascade cyclizations of polyepoxides enable the efficient and rapid construction of polyether skeletons. In this study, we discovered a method for switching the cyclization mode from tetrahydrofuran to tetrahydropyran (THP) formation in epoxide-opening cascades of polyepoxides. The THP formation proceeded via an epoxonium-ion intermediate by simple heating in neutral water. Next, by expanding the switching reaction, we successfully established a "ring-size-divergent" synthetic strategy that enabled the synthesis of the five-, six-, and seven-membered ether rings from identical diepoxide cyclization precursors under simple acidic or neutral conditions. The "ring-size-divergent" synthetic strategy was applied to the short divergent synthesis of nerolidol-type sesquiterpenoids and feroniellins, resulting in the revision of the proposed stereochemistry of certain natural products and the determination of all of the absolute configurations. Additionally, the anti-inflammatory activities of the synthetic samples were evaluated.

Varenicline enhances recognition memory via α7 nicotinic acetylcholine receptors in the medial prefrontal cortex in male mice

Previous studies postulated that chronic administration of varenicline, a partial and full agonist at α4β2 and α7 nicotinic acetylcholine receptors (nAChRs), respectively, enhances recognition memory. However, whether its acute administration is effective, on which brain region(s) it acts, and in what signaling it is involved, remain unknown. To address these issues, we conducted a novel object recognition test using male C57BL/6J mice, focusing on the medial prefrontal cortex (mPFC), a brain region associated with nicotine-induced enhancement of recognition memory. Systemic administration of varenicline before the training dose-dependently enhanced recognition memory. Intra-mPFC varenicline infusion also enhanced recognition memory, and this enhancement was blocked by intra-mPFC co-infusion of a selective α7, but not α4β2, nAChR antagonist. Consistent with this, intra-mPFC infusion of a selective α7 nAChR agonist augmented object recognition memory. Furthermore, intra-mPFC co-infusion of U-73122, a phospholipase C (PLC) inhibitor, or 2-aminoethoxydiphenylborane (2-APB), an inositol trisphosphate (IP3) receptor inhibitor, suppressed the varenicline-induced memory enhancement, suggesting that α7 nAChRs may also act as Gq-coupled metabotropic receptors. Additionally, whole-cell recordings from mPFC layer V pyramidal neurons in vitro revealed that varenicline significantly increased the summation of evoked excitatory postsynaptic potentials, and this effect was suppressed by U-73122 or 2-APB. These findings suggest that varenicline might acutely enhance recognition memory via mPFC α7 nAChR stimulation, followed by mPFC neuronal excitation, which is mediated by the activation of PLC and IP3 receptor signaling. Our study provides evidence supporting the potential repositioning of varenicline as a treatment for cognitive impairment.

Two New Eremophilane-Type Sesquiterpenoids from Japanese Liverwort Bazzania japonica

Two new eremophilane-type sesquiterpenoids, fusumaols A (1) and B (2), were isolated from the stem-leafy liverwort, Bazzaniajaponica collected in Mori-Machi, Shizuoka, Japan. Their structures were established using extensive spectroscopic (IR, MS, and 2D NMR) data, and the absolute configuration of 1 was determined by the modified Mosher's method. This is the first time eremophilanes have been discovered in the liverwort genus Bazzania. Compounds 1 and 2 were evaluated for their repellent activity against the adult population of the rice weevil Sitophilus zeamais using the modified filter paper impregnation method. Both sesquiterpenoids showed moderate repellent activities.

Dose-dependent alkaloid sequestration and N-methylation of decahydroquinoline in poison frogs

Sequestration of chemical defenses from dietary sources is dependent on the availability of compounds in the environment and the mechanism of sequestration. Previous experiments have shown that sequestration efficiency varies among alkaloids in poison frogs, but little is known about the underlying mechanism. The aim of this study was to quantify the extent to which alkaloid sequestration and modification are dependent on alkaloid availability and/or sequestration mechanism. To do this, we administered different doses of histrionicotoxin (HTX) 235A and decahydroquinoline (DHQ) to captive-bred Adelphobates galactonotus and measured alkaloid quantity in muscle, kidney, liver, and feces. HTX 235A and DHQ were detected in all organs, whereas only DHQ was present in trace amounts in feces. For both liver and skin, the quantity of alkaloid accumulated increased at higher doses for both alkaloids. Accumulation efficiency in the skin increased at higher doses for HTX 235A but remained constant for DHQ. In contrast, the efficiency of HTX 235A accumulation in the liver was inversely related to dose and a similar, albeit statistically nonsignificant, pattern was observed for DHQ. We identified and quantified the N-methylation of DHQ in A. galactonotus, which represents a previously unknown example of alkaloid modification in poison frogs. Our study suggests that variation in alkaloid composition among individuals and species can result from differences in sequestration efficiency related to the type and amount of alkaloids available in the environment.

Furanocembranoid from the Okinawan soft coral Sinularia sp

One new furanocembranoid diterpene, 11-hydroxy-Δ¹²⁽¹³⁾-pukalide (1), along with six known secondary metabolites, 11-acetoxy-Δ¹²⁽¹³⁾-pukalide (2), 13α-acetoxypukalide (3), pukalide (4), 3α-methoxyfuranocembranoid (5), Δ⁹⁽¹⁵⁾-africanene (6), and methyl (5'E)-5-(2',6'-dimethylocta-5',7'-dienyl)furan-3-carboxylate (7) were isolated from the Okinawan soft coral Sinularia sp. Their chemical structures were elucidated based on spectroscopic analysis (FTIR, NMR, and HRESIMS), and the relative stereochemistry of 1 was determined by NOESY experiments and acetylation, which yielded derivative 2. In addition, compounds 1 and 7 exhibited toxicity in the brine shrimp lethality test.

Asymmetric Total Synthesis of Toxicodenane A by Samarium-Iodide-Induced Barbier-Type Cyclization and Its Cell-Protective Effect against Lipotoxicity

The asymmetric total synthesis of toxicodenane A, a sesquiterpenoid expected to be promising for diabetic nephropathy, was achieved. In the synthesis, a samarium iodide (SmI₂)-induced Barbier-type cyclization and a regio- and stereoselective allylic oxidation followed by a dehydration cyclization were employed as key steps. Furthermore, the first asymmetric syntheses of both enantiomers were accomplished using the previously mentioned synthetic strategy. Finally, the synthetic compounds significantly inhibited lipotoxicity-mediated inflammatory and fibrotic responses in mouse renal proximal tubular cells.

Asymmetric Total Syntheses, Stereostructures, and Cytotoxicities of Marine Bromotriterpenoids Aplysiol B (Laurenmariannol) and Saiyacenol A

There are marine cytotoxic bromotriterpenoids, named the thyrsiferol family that are structurally characterized by some tetrahydropyran (THP) and tetrahydrofuran (THF) rings. The thyrsiferol family belongs to natural products that are often difficult to determine their stereostructures even by the current, highly advanced spectroscopic methods, especially in acyclic systems including stereogenic tetrasubstituted carbon centers. In such cases, it is effective to predict and synthesize the possible stereostructures. Herein, to elucidate ambiguous stereostructures and unassigned absolute configurations of aplysiol B, laurenmariannol, and saiyacenol A, members of the thyrsiferol family, we carried out their asymmetric chemical syntheses featuring 6‐exo and 5‐exo oxacyclizations of epoxy alcohol precursors and 6‐endo bromoetherification of a bishomoallylic alcohol. In this paper, we report total assignments of their stereostructures through their asymmetric chemical syntheses and also their preliminary cytotoxic activities against some tumor cells. These results could not have been achieved without depending on asymmetric total synthesis.

Establishing a "Ring-Size-Divergent" Synthetic Strategy: Synthesis, Structural Revision, and Absolute Configuration of Feroniellins

Feroniellin analogs isolated from Feroniella lucida possess a furanocoumarin skeleton connected to monoterpenic five- to seven-membered ethereal rings by an ether linkage and exhibit a broad spectrum of biological activities. In this contribution, we intended to establish a "ring-size-divergent" synthetic strategy for the monoterpenic five- to seven-membered ethereal rings through the chemical sythesis of feroniellins. The short and comprehensive synthesis of feroniellins was achieved in only two steps from easily available bergamottin based on the "ring-size-divergent" strategy. In addition, these syntheses resulted in revision of the proposed structures for feroniellins A and B and the determination of all the absolute configurations of feroniellins; their preliminary anti-inflammatory activities were investigated as well.

One-Step Synthesis of the 1-Azaspiro[5.5]undecane Skeleton Characteristic of Histrionicotoxin Alkaloids from Linear Substrates via Hg(OTf)2 -Catalyzed Cycloisomerization

Histrionicotoxin (HTX) alkaloids isolated from the poison arrow frogs possess a unique structure characterized by a 1-azaspiro[5.5]undecane skeleton common to the HTX family. The unique molecular architecture of HTXs and the interest as potential target drugs have prompted synthetic chemists to promote the total synthesis so far. However, all of the synthetic strategies to access the 1-azaspiro[5.5]undecane framework of HTXs take a multistep approach from linear starting materials due to stepwise construction of either six-membered carbo- or azacycle. Herein, we report the direct one-step construction of the 1-azaspiro[5.5]undecane skeleton from linear amino ynone substrates bearing an N-methoxycarbonyl group utilizing our mercuric triflate (Hg(OTf)₂ )-catalyzed cycloisomerization reaction. The utility of this novel methodology was demonstrated by the total and formal syntheses of HTX-235A and HTX-283A, respectively, from the azaspirocycle.

Impact of frailty on super elderly patients with peripheral artery disease from the I-PAD 3 year registry

Background

Unlike age, frailty is often not taken into account in treatment indications of Endovascular treatment (EVT). One of the reason is that there was little known the relationship between frailty and the outcome of EVT for super elderly patients with peripheral artery disease (PAD). We investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Purpose

To investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Methods

From August 2015 to July 2016, 335 consecutive patients who underwent EVT were enrolled in the I-PAD registry from 7 institutes in Nagano prefecture. Among them, we selected and analyzed 91 super elderly PAD patients (≥80 years-old) and divided them into two groups:those with moderate or higher frailty (Clinical Frailty Scale (CFS) ≥6, n=28) and those without (CFS ≤5, n=63). The primary endpoints were cardiovascular death and major adverse cardiovascular and limb events (MACLE), defined as a composite of cardiovascular death, myocardial infarction, stroke, admission for heart failure, major amputation and revascularization.

Results

The median follow-up period was 2.7 years. Freedom rate from cardiovascular death and MACLE were significantly lower among patients with moderate or higher frailty than among those without (47.0% vs. 58.0%, P=0.03; 39.1% vs. 68.5%, P<0.01).

Conclusion

The prognosis of super elderly patients with moderate or higher frailty is worse than those without.

Funding Acknowledgement

Type of funding source: None

Use of whole-body cryosectioning and desorption electrospray ionization mass spectrometry imaging to visualize alkaloid distribution in poison frogs

Ambient mass spectrometry is useful for analyzing compounds that would be affected by other chemical procedures. Poison frogs are known to sequester alkaloids from their diet, but the sequestration pathway is unknown. Here, we describe methods for whole-body cryosectioning of frogs and use desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to map the orally administered alkaloid histrionicotoxin 235A in a whole-body section of the poison frog Dendrobates tinctorius. Our results show that whole-body cryosectioning coupled with histochemical staining and DESI-MSI is an effective technique to visualize alkaloid distribution and help elucidate the mechanisms involved in alkaloid sequestration in poison frogs.

0453 Longitudinal Relationship Between Insomnia and Work Productivity in Japanese City Government Employees

Introduction

“Presenteeism” refers to the decrease in productivity in employees who are present but not functioning at full capacity due to illness or other medical conditions. It is reported that the cost of presenteeism to businesses is 10 times higher than absenteeism (away from work due to illness or disability). Relative presenteeism is a ratio of actual performance to the performance of most workers at the same job. We analyzed effects of insomnia and depression two years before on presenteeism in a Japanese working population.

Methods

Questionnaire survey was conducted as a part of a cohort study named “Night in Japan Home Sleep Monitoring Study (NinJaSleep Study)” in 2016 and 2018. Participants were the city government employees in a rural city in Shiga prefecture, Japan. Presenteeism, insomnia and depression were analyzed by WHO-HPQ (Health and Work Performance Questionnaire), ISI (insomnia severity index) and PHQ-9 (Patient Depression Questionnaire), respectively. Pearson correlation coefficient analyses were performed to determine the strength of the association between two variables. Logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) of poor relative presenteeism (the lowest tertile of the relative presenteeism scores) after 2-year follow up.

Results

1143 subjects (participation rate: 61.7%, 36.7% male, 44.5±11.4 years, BMI: 22.3±3.30) participated in both 2016 and 2018. Participants with poor productivity (poor relative presenteeism) in 2018 was significantly associated with ISI in 2016 (OR: 1.050, 95%CI: 1.010-1.090, p=0.013) but not with PHQ-9 in 2016 (OR: 1.008, 95%CI: 0.972-1.045, p=0.664) after adjusting for age, gender and BMI. Positive correlation was found between the total score of ISI and item 3 of PHQ-9 which asks insomnia or hypersomnia symptom (r=0.6122, P<0.0001).

Conclusion

Insomnia may be an independent risk factor for poor presenteeism. ISI may be useful to predict poor productivity in the future.

Support

Supported in part by a research grant from Investigator-Initiated Studies Program of Merck Sharp & Dohme Corp. / MSD K.K. The opinions expressed in this paper are those of the authors and do not necessarily represent those of Merck Sharp & Dohme Corp. / MSD K.K.”

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

P943The impact of diabetes on patients with frail after endovascular treatments: from I-PAD registry

Background

Diabetes mellitus (DM) is known to be one of the risks of arteriosclerosis. However, it is still unknown whether DM is a risk factor also in secondary prevention of frail patients after endovascular treatments (EVT)

Purpose

To investigate impact of diabetes on patients with frail after EVT.

Methods

From July 2015 to July 2016, 371 consecutive PAD patients who performed EVT were enrolled in I-PAD registry. We could conduct follow up survey 361 patients (446 lesions) and divided into 2 groups; with diabetes (185 patients, 226 lesions) or without diabetes (176 patients, 220 lesions) and analyzed. And among them,we selected 96 patients with frail and divided into 2 groups; with diabetes (49 patients, 70 lesions) or without diabetes (46 patients, 58 lesions) and analyzed. We defined frail patients as the patients with Clinical Frailty Scale 5 (mild frail) or higher. The primary end point was all-cause-death and major adverse limb events (MALE: TLR, TVR, major amputations) at 1 year.

Result

At 1 years in the patients group with diabetes, overall survival and freedom from MALE were significantly lower (81.7% vs 95.8% P<0.0001; 80.0% vs 94.6%, P<0.0001) than the group without diabetes.Among the patients with frail, between the patients group with diabetes and the group without, there is no significant differences in overall survival and freedom from MALE (88.2% vs 88.9% P=0.83; 80.7% vs 84.1%, P=0.55) at 5 years.

Conclusion

The prognosis of patients with diabetes after EVT was worse than the patient without. On the other hand, the prognosis of frail patients with diabetes after EVT was no difference with the frail patient without diabetes in this study.

Critical Switching of Cyclization Modes of Polyepoxides in Acidic Aqueous Media and Neutral Water: Synthesis and Revised Structure of a Nerolidol-Type Sesquiterpenoid

Biomimetic epoxide-opening cascades of polyepoxides enable the efficient and rapid construction of polyether frameworks. Herein, we show that the epoxide-opening cascade cyclization that affords tetrahydrofuran products in acidic aqueous media produces tetrahydropyran (THP) in neutral water. THP formation proceeded by simply heating polyepoxides in neutral water and followed a different cyclization mode from those observed so far. The novel cascade cyclization in H₂ O was applied to the synthesis of a new nerolidol-type sesquiterpenoid, resulting in revision of the proposed structure and determination of the absolute configuration.

Correlation and Linear Regression between Blood Pressure Decreases after a Test Dose Injection of Propofol and that following Anaesthesia Induction

Propofol reduces systemic vascular resistance and suppresses cardiac function when injected rapidly. In this study we investigated whether blood pressure decrease after a minimal dose (test-dose) injection of propofol correlates with that after an induction-dose injection.

Patients were randomly divided into two groups; anaesthesia was induced in group A (n=60) using 1.5 mg/kg propofol and in group B (n=61) using 2.0 mg/kg. Blood pressure reduction after a minimal dose injection (0.4 mg/kg) was examined non-invasively prior to anaesthetic induction. Bispectral Index monitoring was measured and sedation level scored to evaluate anaesthetic depth.

After the minimal dose injection, 18 of 121 patients showed behaviour suggesting minor disinhibition, five patients were sedated and seven were drowsy. Oxygen saturation was not significantly changed after test-dose injection. Reduction in systolic blood pressure (mean±SD) was 17±11 mmHg after the minimal dose injection, 42±20 mmHg after a 1.5 mg/kg induction dose injection, and 42±22 mmHg after a 2.0 mg/kg induction-dose injection. In both groups, blood pressure after induction was significantly lower than the control value (P<0.05). In both groups, a positive correlation was observed between blood pressure reduction after the minimal dose injection and that after the induction-dose injection [P<0.01, R value for systolic blood pressure correlation in group A 0.712 (P<0.01) and in group B 0.758 (P<0.01)].

We concluded there was a positive correlation between blood pressure reduction after a minimal (test-dose) injection and that after an induction-dose injection.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Evaluation of Aculeatin and Toddaculin Isolated from Toddalia asiatica as Anti-inflammatory Agents in LPS-Stimulated RAW264 Macrophages

Anti-inflammatory activity of aculeatin and toddaculin, which are coumarins with a similar structure isolated from Toddalia asiatica (L.) LAM., was evaluated using lipopolysaccharide (LPS)-stimulated RAW264 mouse macrophage cells. Both aculeatin and toddaculin significantly inhibited mRNA expression of inflammatory mediators and nitric oxide production. Furthermore, Toddaculin suppressed LPS-induced phosphorylation of p38 and extracellular signal-regulated kinase (ERK)1/2 and inhibited LPS-induced activation of nuclear factor-kappaB (NF-κB). However, aculeatin did not exhibit such effects, suggesting that aculeatin and toddaculin suppress LPS-induced inflammation of RAW264 cells via different mechanisms. The cellular uptake of these compounds was also evaluated. Toddaculin was detected in RAW264 cells after 4 and 24 h. However, aculeatin levels were not observed in RAW264 cells at all incubation intervals. These results indicate that de-epoxidation of a prenyl group can increase hydrophobicity of molecule and is thought to accelerate cellular uptake and/or interactions with the phospholipid bilayers of cell membranes.

Antioxidants from the Brown Alga Dictyopteris undulata

An investigation of anti-oxidative compounds from the brown alga Dictyopteris undulata has led to the isolation and identification of isozonarol, isozonarone, chromazonarol, zonaroic acid and isozonaroic acid. Their structures were identified by comparison of MS and NMR spectra. Full NMR assignment and absolute configuration of isozonaroic acid are described. Isozonarol showed the most potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity among the compounds isolated.

Early results of a randomized two-by-two factorial phase II trial comparing neoadjuvant chemotherapy with two and four courses of cisplatin/S-1 and docetaxel/cisplatin/S-1 as neoadjuvant chemotherapy for locally advanced gastric cancer

Background

Neoadjuvant chemotherapy (NAC) is a promising method of improving the survival of resectable gastric cancer. Cisplatin/S-1 (CS) and docetaxel/cisplatin/S-1 (DCS) are both effective against metastatic gastric cancer. This report clarified the impact of these regimens on early endpoints, including the pathological responses, chemotherapy-related toxicities, and surgical results.

Methods

Patients with M0 and either T4 or T3 in case of junctional cancer or scirrhous type received two or four courses of cisplatin (60 mg/m2 at day 8)/S-1 (80 mg/m2 for 21 days with 1 week rest) or docetaxel (40 mg/m2 at day 1)/cisplatin (60 mg/m2 at day 1)/S-1 (80 mg/m2 for 14 days with 2 weeks rest) as NAC. Patients then underwent D2 gastrectomy and adjuvant S-1 chemotherapy for 1 year. The primary endpoint was the 3-year overall survival.

Results

Between October 2011 and September 2014, 132 patients were assigned to receive CS (n = 66; 33 in 2 courses and 33 in 4 courses) or DCS (n = 66; 33 in 2 courses and 33 in 4 courses). The respective major grade 3 or 4 hematological toxicities (CS/DCS) were leukocytopenia (14.1%/26.2%), neutropenia (29.7%/47.7%), anemia (14.1%/12.3%), and platelet reduction (3.1%/1.5%). The rate of pathological response, defined as a complete response or < 10% residual cancer remaining, was 19.4% in the CS group and 15.4% in the DCS group, and 15.6% in the two-course group and 19.0% in the 4-course group. The R0 resection rate was 72.7% in the CS group and 81.8% in the DCS group and 80.3% in the two-course group and the 74.2% in the four-course group. No treatment-related deaths were observed.

Conclusions

Our results do not support three-drug therapy with a taxane over two-drug therapy, or any further treatment beyond two cycles as an attractive candidate for the test arm of NAC.

Electrophysiological effects of desflurane in children with Wolff-Parkinson-White syndrome: a randomized crossover study

BACKGROUND

We hypothesized that, compared with propofol, desflurane prolongs the antegrade accessory pathway effective refractory period (APERP) in children undergoing radiofrequency catheter ablation for Wolff-Parkinson-White (WPW) syndrome.

METHODS

In this randomized crossover study, children aged 4.1-16.1 years undergoing radiofrequency catheter ablation for WPW syndrome were randomly divided into four groups according to the concentration of desflurane and anesthetics used in the first and the second electrophysiological studies (EPS). After induction of general anesthesia with propofol and tracheal intubation, they received one of the following regimens: 0.5 minimum alveolar concentration (MAC) desflurane (first EPS) and propofol (second EPS) (Des0.5-Prop group, n = 8); propofol (first EPS) and 0.5 MAC desflurane (second EPS) (Prop-Des0.5 group, n = 9); 1 MAC desflurane (first EPS) and propofol (second EPS) (Des1.0-Prop group, n = 10); propofol (first EPS) and 1 MAC desflurane (second EPS) (Prop-Des1.0 group, n = 9). Radiofrequency catheter ablation was performed upon completion of EPS. Sample size was determined to detect a difference in the APERP.

RESULTS

Desflurane at 1.0 MAC significantly prolonged the APERP compared with propofol, but did not affect the sinoatrial conduction time, atrio-His interval or atrioventricular node effective refractory period. Supraventricular tachycardia was induced in all children receiving propofol, but not induced in 1 and 4 children receiving 0.5 MAC and 1.0 MAC desflurane, respectively.

CONCLUSION

Desflurane enhances the refractoriness and may block the electrical conduction of the atrioventricular accessory pathway, and is therefore not suitable for use in children undergoing radiofrequency catheter ablation for WPW syndrome.

Pleth variability index can predict spinal anaesthesia-induced hypotension in patients undergoing caesarean delivery

BACKGROUND

Spinal anaesthesia carries a risk of hypotension. We hypothesized that pleth variability index and perfusion index would assess maternal volume status, and thus, allow identification of patients at higher risk of developing hypotension after spinal anaesthesia for caesarean delivery.

METHODS

Fifty patients undergoing elective caesarean delivery were enrolled. All patients received spinal anaesthesia with 0.5% hyperbaric bupivacaine (10 mg) and fentanyl (10 mcg). Blood pressure was measured every minute. Pleth variability index and perfusion index were automatically measured throughout the procedure using pulse oximetry on the index finger. In case of hypotension (systolic blood pressure below 90 mmHg or 80% of the baseline value), ephedrine 5 mg was administered. Receiver-operating characteristic and multivariate logistic regression analyses for spinal anaesthesia-induced hypotension were performed.

RESULTS

Hypotension occurred in 32 patients (64%). The areas under the receiver-operating characteristic curve were 0.751 (95% confidence interval: 0.597-0.904) for pleth variability index before anaesthesia, 0.793 (95% confidence interval: 0.655-0.930) for pleth variability index after anaesthesia and 0.731 (95% confidence interval: 0.570-0.892) for perfusion index change (percent change in perfusion index induced by spinal anaesthesia). The optimal threshold value of pleth variability index (after anaesthesia) for predicting hypotension was 18% (sensitivity: 78.1%, specificity: 83.3%). Pleth variability index after spinal anaesthesia was an independent factor for hypotension (odds ratio: 1.21, P = 0.041).

CONCLUSIONS

Pleth variability index after spinal anaesthesia was a good predictor of spinal anaesthesia-induced hypotension in patients undergoing caesarean delivery. In addition, perfusion index change after spinal anaesthesia has the potential to predict hypotension.

Formal total synthesis of histrionicotoxin alkaloids via Hg(OTf)2-catalyzed cycloisomerization and SmI2-induced ring expansion

The efficient formal total synthesis of histrionicotoxin alkaloids was achieved via Hg(OTf)₂-catalyzed cycloisomerization and SmI₂-induced ring expansion.