Iron complexes supported by silyl-NHC chelate ligands: synthesis and use for double hydroboration of nitriles.

Iron complexes bearing new silyl-NHC bidentate ligands were synthesised by treating Fe3(CO)12 with a mixture of N-(hydrosilyl)methyl imidazolium salts and a base. These complexes showed high performance in the catalytic double hydroboration of nitrile with pinacolborane (HBpin) to produce N,N-bis(boryl)amine by a combination of UV irradiation and mild heating (60 °C). The product yields for the hydroboration of aromatic and aliphatic nitriles reached 85%-95% (NMR) using an iron complex (5 mol%). Reducing the loading amount of the iron complex to 0.5 mol% still afforded the products in high yields. An analogous ruthenium complex, which was similarly synthesised using Ru3(CO)12, showed lower activity. Stoichiometric reactions of the iron complex with nitriles afforded Fe(0)-N-silylimine complexes, which may be dormant states in nitrile hydroboration. A catalytic mechanism including Fe(0) N-silylimine species is proposed.

Body positioning-related laryngeal narrowing pattern and expiratory mechanical constraints in advanced chronic obstructive pulmonary disease: A case report.

We previously reported that laryngeal widening led to improved exercise tolerance in COPD. However, it is not clear whether laryngeal narrowing occurs as a compensatory response to tracheal movement or is affected by posture. Here, we report the case of an advanced COPD patient whose more prolonged expiration in a head-forward leaning position compared with that in a neck-extended position occurred with an excessive duration of severe laryngeal narrowing without tracheal obstruction, which led to exercise intolerance with expiratory mechanical constraints. This case provided useful insights into the regulation of the upper airway with body positioning for improving exercise tolerance.

Neutral Chromium Complex with a Cr≡Si Triple Bond: Synthesis and Photoinduced H-H and Benzene C-H Bond Activation.

A neutral silylyne complex with a Cr≡Si triple bond was prepared by dehydrogenation of a chromium silylene complex with Cr-H and Si-H bonds, and was isolated as monomeric crystals, unlike dimeric forms of its tungsten and molybdenum congeners. The strong Cr(δ-)-Si(δ+) bond polarity was revealed by the reaction with MeOH and DFT calculations. The chromium silylyne complex reacted with H2 under LED (365 nm) irradiation to reproduce the precursor silylene complex with a (H)Cr=Si(H) moiety, as a result of 1,2-H-H addition across the Cr≡Si triple bond. Similarly, the chromium silylyne complex reacted with benzene under irradiation to afford an 1,2-addition product with a (H)Cr=Si(Ph) moiety, via benzene C-H bond activation accompanied by Si-C bond forming.

Π-Character of Chromium Germylyne Complex in the Reactions with Enone, Butadiene, and Alkynes: Formation of Germacycles through [2+4] Cycloaddition with Conjugated Molecules.

Germylyne complex Cp*(OC)2 Cr≡Ge{C(SiMe3 )3 } (1) reacted with methyl vinyl ketone to give an η3 -allyl complex 2 with an oxagermacyclopentenyl ring. An analogous η3 -allyl complex 3 with a germacyclopentenyl ring was obtained by the reaction with butadiene, a non-polar conjugated molecule, under photoirradiation. These reactions are accompanied by cleavage of the Cr≡Ge triple bond. On the other hand, the reactions of complex 1 with alkynes under photoirradiation resulted in clean substitution of a CO ligand of 1 to afford (η2 -alkyne)germylyne complexes, where the Cr≡Ge triple bond is intact.

Neutral Silylyne Complex of Molybdenum: Synthesis, Properties, and Access to Silaiminoacyl Complexes via [2+3] Cycloaddition.

A neutral silylyne complex of molybdenum was synthesized by the stepwise dehydrogenation method and its properties were compared with those of the tungsten analog. The complex takes a dimeric form as crystals but afford a monomer-dimer equilibrium in solution. The replacement of the central metal from W to Mo led to a monomer dominant (~98 %) solution at room temperature. The monomer-dimer dynamics was investigated based on thermodynamic parameters. The molybdenum silylyne complex underwent [2+2] cycloaddition with alkynes much faster than the tungsten analog. The reactions with organic azides led to the formation of the first example of silaiminoacyl complexes through [2+3] cycloaddition. The structures and bonding aspects of the products were clarified by multiple measurements and DFT calculations.

Laryngeal widening and adequate ventilation by expiratory pressure load training improve aerobic capacity in COPD: a randomised controlled trial.

RATIONALE: Despite strategies acting on peripheral airway obstruction in chronic obstructive pulmonary disease (COPD), exercise intolerance remains inadequately improved. We hypothesised that laryngeal narrowing is a potential treatment target of expiratory pressure load training (EPT) to improve exercise intolerance in COPD. METHODS: The effect of 3-month EPT was assessed in 47 patients with COPD divided into Global Initiative for Chronic Obstructive Lung Disease (GOLD) mild-to-moderate (I-II) and severe-to-very severe (III-IV), randomly allocating 1:1 to EPT or control groups. The primary outcome was endurance time in the constant work rate exercise test in GOLD III-IV patients. RESULTS: Compared with controls, EPT increased: (1) endurance time, with estimated treatment effect: +703 (95% CI: 379 to 1031) s, p=0.0008 (GOLD I-II); +390 (95% CI: 205 to 574) s, p=0.0006 (GOLD III-IV); (2) peak oxygen uptake (p=0.0086 in GOLD I-II; p=0.0004 in GOLD III-IV); (3) glottic dilatation ratio at maximum collapse on laryngoscopy in the submaximal exercise (p=0.0062 in GOLD I-II; p=0.0001 in GOLD III-IV); and (4) the inflection point of expiratory tidal volume relative to minute ventilation during the incremental exercise (p=0.0015 in GOLD I-II; p=0.0075 in GOLD III-IV). Across GOLD grades, the responses of glottic dilatation ratio at maximum collapse and the expiratory tidal volume at the inflection point were selected as more influential variables correlating with the improvement in peak oxygen uptake and endurance time, respectively. CONCLUSION: These results show that EPT improved aerobic capacity and endurance time with larger laryngeal widening and adequate ventilation despite advanced COPD. TRIAL REGISTRATION NUMBER: UMIN000041250.

Iridium and rhodium complexes bearing a silyl-bipyridine pincer ligand: synthesis, structures and catalytic activity for C-H borylation of arenes.

Unsaturated 16-electron iridium and rhodium complexes bearing a silyl-bipyridine-based SiNN-pincer ligand (BpySiNN) were synthesised and characterised by X-ray crystallography and NMR spectroscopy. The iridium-BpySiNN complex facilitated the catalytic C(sp2)-H borylation of arenes to give arylboronate esters in high yields (≥93%) under mild conditions (∼40 °C).

Increased Oxygen Extraction by Pulmonary Rehabilitation Improves Exercise Tolerance and Ventilatory Efficiency in Advanced Chronic Obstructive Pulmonary Disease.

BACKGROUND: In cardiopulmonary exercise testing (CPET), oxygen uptake (V'O2) is calculated using the product of minute ventilation (V'E) and the difference between inspiratory and expiratory O2 concentrations (ΔFO2). However, little is known about the response of ΔFO2 to pulmonary rehabilitation (PR). The aim of the present study was (1) to investigate whether PR increases peak V'O2, based on whether ΔFO2 or V'E at peak exercise increase after PR, and (2) to investigate whether an improvement in ΔFO2 correlates with an improvement in ventilatory efficiency. METHODS: A total of 38 patients with severe and very severe COPD, whose PR responses were evaluated by CPET, were retrospectively analyzed. RESULTS: After PR, peak V'O2 was increased in 14 patients. The difference in ΔFO2 at peak exercise following PR correlated with the difference in peak V'O2 (r = 0.4884, p = 0.0019), the difference in V'E/V'CO2-nadir (r = -0.7057, p < 0.0001), and the difference in V'E-V'CO2 slope (r = -0.4578, p = 0.0039), but it did not correlate with the difference in peak V'E. CONCLUSIONS: The increased O2 extraction following PR correlated with improved exercise tolerance and ventilatory efficiency. In advanced COPD patients, a new strategy for improving O2 extraction ability might be effective in those in whom ventilatory ability can be only minimally increased.

Corrigendum: Oxygen Extraction Based on Inspiratory and Expiratory Gas Analysis Identifies Ventilatory Inefficiency in Chronic Obstructive Pulmonary Disease.

[This corrects the article DOI: 10.3389/fphys.2021.703977.].

Oxygen Extraction Based on Inspiratory and Expiratory Gas Analysis Identifies Ventilatory Inefficiency in Chronic Obstructive Pulmonary Disease.

Aims: In contrast to cardiovascular disease, low rather than high ventilatory inefficiency, evaluated by the minute ventilation-carbon dioxide output (V'E-V'CO2)-slope, has been recognized as being related to greater disease severity in chronic obstructive pulmonary disease (COPD). To better care for patients with cardiopulmonary disease, understanding the physiological correlation between ventilatory inefficiency and exercise limitation is necessary, but remains inadequate. Given that oxygen uptake (V'O2) evaluated by cardiopulmonary exercise testing (CPET) depends on both the ventilatory capability and oxygen extraction, i.e., the difference between inspiratory and expiratory oxygen concentration (ΔFO2), the aim of this study was to investigate the correlations between V'E-V'CO2-slope and the ΔFO2 during exercise and their physiological implications in patients with COPD. Methods: A total of 156 COPD patients (mean age, 70.9 ± 7.2 years) with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages I-IV and 16 controls underwent CPET with blood gas analysis. Results: With the progression of COPD, mechanical ventilatory constraints together with a slower respiratory frequency led to exertional respiratory acidosis. In GOLD IV cases, (1) decrease in the dependence of reduced peak V'O2 on V'E led to an increase in its dependence on peak ΔFO2 during exercise; and (2) the ΔFO2-V'CO2-slope became steeper, correlating with the severity of exertional respiratory acidosis (r = 0.6359, p < 0.0001). No significant differences in peak exercise ΔFO2 or V'E-V'CO2-slope were observed among the various GOLD stages. In all subjects, including controls, peak exercise ΔFO2 had the strongest correlation with the V'E-V'CO2-slope (r = -0.8835, p < 0.0001) and correlated well with body mass index (r = 0.3871, p < 0.0001), although it did not correlate with the heart rate-V'CO2-relationship and V'E. Conclusions: Ventilatory efficiency related to CO2 clearance might depend on exertional oxygen extraction in the body. Measuring ΔFO2 might be a key component for identifying ventilatory inefficiency and oxygen availability. Increasing ΔFO2 would help to improve ventilatory inefficiency and exercise tolerance separately from cardiac and ventilatory capability in COPD patients.

High-dose cytarabine chemotherapy (≥4 g/m2/day) before allogeneic hematopoietic stem cell transplantation for non-core-binding-factor AML in the first complete remission.

Benefit of high-dose cytarabine (HD-AraC) for acute myeloid leukemia (AML) prior to allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unknown. We retrospectively analyzed data from 79 non-core-binding-factor AML patients who underwent allo-HSCT in their first complete remission (CR1). In univariate analysis, HD-AraC (≥4 g/m2/day) before allo-HSCT improved disease-free survival (DFS) (p = .018), overall survival (OS) (p = .029), and cumulative incidence of relapse (CIR) (p = .033). Four-year DFS, OS, and CIR of patients receiving and not receiving HD-AraC were 79% vs. 49%, 82% vs. 56%, and 18% vs. 42%, respectively. In multivariate analysis, HD-AraC was a positive prognostic factor for DFS (hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.14-0.88), OS (HR = 0.37, 95% CI: 0.14-0.99), and CIR (HR = 0.38, 95% CI; 0.14-1.0). Our study demonstrates that HD-AraC before allo-HSCT at a dose ≥4 g/m2/day is effective for treating AML patients in CR1.

Reactions of a Silylyne Complex with Aldehydes: Formation of W-Si-O-C Four-Membered Metallacycles and Their Metathesis-Like Fragmentation.

A tungsten silylyne complex having a W≡Si triple bond reacted with two molecules of aldehydes at room temperature to give W-Si-O-C four-membered metallacycles by [2+2] cycloaddition and subsequent formyl hydrogen transfer from one aldehyde molecule to another. Upon heating to 70 °C, the four-membered metallacycles underwent metathesis-like fragmentation cleanly to afford carbyne complexes and "silanoic esters," in a manner similar to that of metallacyclobutadiene, an intermediate of alkyne metathesis reactions, and dimerization of the latter products gave 1,3-cyclodisiloxanes. The "silanoic ester" was also trapped by pivalaldehyde to give a [2+2] cycloaddition product in high yield.

Clinical Implications of t(11;14) in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation.

Conventional cytogenetic analyses and fluorescent in situ hybridization (FISH) are helpful for stratifying patients with multiple myeloma (MM) into high-risk [t(4;14), t(14;16), and/or del 17p] and standard-risk [t(11;14)] categories. However, the prognosis of patients with MM treated with autologous stem cell transplantation (ASCT) stratified according to these categories remains unclear. This retrospective observational study analyzed 97 patients with MM who received a single, planned ASCT after treatment with 200 mg/m2 melphalan between 2001 and 2011. The patients were grouped according to chromosomal abnormality, including t(11;14) (n = 45), t(4;14) (n = 31), del 17p (n = 10), t(11;14) with del 17p (n = 7), and t(4;14) with del 17p (n = 4). Median overall survival (OS) of the t(11;14) group (64.1 months) was not significantly different from that of the t(4;14) group (not reached), but it was significantly longer than that of the del 17p group (23.0 months; P = .002). G-banding revealed that the median OS of the t(11;14) group with additional chromosomal abnormalities (ACAs) (46.2 months) was significantly shorter than that of the t(11;14) group without ACAs (not reached; P = .005) and the t(4;14) group (not reached; P = .010). These findings highlight the importance of G-banding in patients with t(11;14) MM.

Outcomes of patients who developed subsequent solid cancer after hematopoietic cell transplantation.

To characterize the outcomes of patients who developed a particular subsequent solid cancer after hematopoietic cell transplantation (HCT), age at cancer diagnosis, survival, and causes of death were compared with the respective primary cancer in the general population, using data from the national HCT registry and population-based cancer registries in Japan. Among 31 867 patients who underwent a first HCT between 1990 and 2013 and had progression-free survival at 1 year, 713 patients developed subsequent solid cancer. The median age at subsequent solid cancer diagnosis was 55 years, which was significantly younger than the 67 years for primary cancer patients in the general population (P < .001). The overall survival probability was 60% at 3 years after diagnosis of subsequent solid cancer and differed according to cancer type. Development of most solid cancers was associated with an increased risk of subsequent mortality after HCT. Subsequent solid cancers accounted for 76% of causes of death. Overall survival probabilities adjusted for age, sex, and year of diagnosis were lower in the HCT population than in the general population for colon, bone/soft tissue, and central nervous system cancers and did not differ statistically for other cancers. In conclusion, most subsequent solid cancers occurred at younger ages than primary cancers, emphasizing the need for cancer screening at younger ages. Subsequent solid cancers showed similar or worse survival compared with primary cancers. Biological and genetic differences between primary and subsequent solid cancers remain to be determined.

[Mitoxantrone, etoposide, and cytarabine combination therapy for acute myeloid leukemia patients failing to achieve a complete remission after induction chemotherapy: a single-center experience].

Optimal salvage chemotherapy has not been established for patients with acute myeloid leukemia (AML) who fail to attain complete remission (CR) after one course of induction chemotherapy. This retrospective study aimed to assess the efficacy and safety of an MEC (mitoxantrone, 6 mg/m2, 1-3 days; etoposide, 80 mg/m2, 1-6 days; cytarabine, 1 g/m2, 1-6 days) regimen in patients with AML who failed to attain CR after one course of induction chemotherapy. Twenty-four patients were included in this study (median age, 58 years; range, 28-79 years). After one course of MEC, 11 patients (45.8%) attained CR. Febrile neutropenia was observed in all patients, and acute infection was observed in 7 patients (29.2%). However, no therapy-related death occurred. All patients eligible for transplantation and who attained CR after MEC salvage chemotherapy underwent allogeneic hematopoietic stem cell transplantation. The MEC regimen exhibited a good response rate with tolerable adverse events. Therefore, the MEC regimen can be safely used as a salvage treatment for patients with AML who failed to attain CR after one course of induction chemotherapy.

Correction to: Impact of hematopoietic stem cell transplantation in patients with relapsed or refractory mantle cell lymphoma.

The original version of this article contained a mistake in fig. 1a. "Autologous HCT(n=111)" should be changed to "Allogeneic HCT (n=51)". Correct figure is presented below.

Population Pharmacokinetics of Vancomycin in Patients Undergoing Allogeneic Hematopoietic Stem-Cell Transplantation.

Vancomycin is a commonly used antimicrobial agent for patients undergoing allogeneic hematopoietic stem-cell transplantation (allo-HSCT). Vancomycin has large inter- and intraindividual pharmacokinetic variability, which is mainly described by renal function; various studies have indicated that vancomycin pharmacokinetics are altered in special populations. However, little is known regarding vancomycin pharmacokinetics in patients undergoing allo-HSCT. Therefore, we aimed to develop a population pharmacokinetic (PopPK) model of vancomycin in patients undergoing allo-HSCT for effective and safe antimicrobial therapy and to develop a vancomycin dosing nomogram for a vancomycin optimal-dosing strategy. In total, 285 observations from 95 patients undergoing allo-HSCT were available. The final PopPK parameter estimates were central volume of distribution (V1, L), 39.2; clearance (L/h), 4.25; peripheral volume of distribution (V2, L), 56.1; and intercompartmental clearance (L/h), 1.95. The developed vancomycin model revealed an increase in V1 and V2 compared with those in the general population that consisted of patients with methicillin-resistant Staphylococcus aureus. Moreover, serum creatinine was reduced because of an increase in the plasma fraction because of destruction of hematopoietic stem cells accompanying allo-HSCT pretreatment, suggesting that the Cockcroft-Gault equation-based creatinine clearance value was overestimated. To our knowledge, this is the first PopPK study to develop a dosing nomogram for vancomycin in patients undergoing allo-HSCT and was proven to be useful in optimizing the dosage and dosing interval of vancomycin in these patients. This strategy will provide more useful information for vancomycin therapy with an evidence-based dose adjustment.