An enantioselective total synthesis and stereochemical revision of (+)-citrinadin B

This manuscript describes an enantioselective synthesis of the naturally occurring alkaloid citrinadin B. The synthetic effort revealed an anomaly in the original structural assignment that has led to the proposal of a stereochemical revision. This revision is consistent with the structures previously reported for a closely related family of alkaloids, PF1270A-C. The synthesis is convergent and employs a stereoselective intermolecular nitrone cyloaddition reaction as a key step.

Synthetic studies toward the citrinadins: enantioselective preparation of an advanced spirooxindole intermediate

This manuscript describes the enantioselective preparation of a spirooxindole that is suited for advancedment to either Citrinadin A or B.

Solid-Phase Modular Synthesis of Park Nucleotide and Lipids I and II Analogues

A solid-phase synthesis of Park nucleotide as well as lipids I and II analogues, which is applicable to the synthesis of a range of analogues, is described in this work. This technique allows highly functionalized macromolecules to be modularly labeled. Multiple steps are used in a short time (4 d) with a single purification step to synthesize the molecules by solid-phase synthesis.

Renoprotective effects of telmisartan on renal injury in obese Zucker rats

The purpose of the present study was to investigate the renoprotective effect of telmisartan, an angiotensin II receptor antagonist, on the early stages of diabetic nephropathy in obese Zucker rats, which is a type 2-related diabetes mellitus model. Telmisartan 1, 3 or 10 mg/kg/day was orally administered to 7-week-old rats that demonstrated glucose tolerance without albuminuria or proteinuria, for 24 consecutive weeks (Experiment A). In another experiment (Experiment B), oral administration of telmisartan 10 mg/kg/day was initiated at the age of 16 weeks after the rats demonstrated marked proteinuria, and continued for 24 weeks. Telmisartan inhibited the increase in proteinuria and albuminuria in a dose-dependent manner, and the inhibition for all telmisartan groups was statistically significant by the completion of administration (Experiment A). Telmisartan also displayed similar inhibitory effects on proteinuria and albuminuria in Experiment B. Histologically, telmisartan [3 and 10 mg/kg/day] was associated with a significant decrease in the progression of glomerulosclerosis, and significantly improved interstitial cell infiltration, interstitial fibrosis and dilation and atrophy of renal tubules. Furthermore, telmisartan treatment was associated with a tendency towards normalized plasma lipids (total cholesterol and triglyceride). Our results suggest that telmisartan has a definite renoprotective effect against renal injury in type II diabetic nephropathy.

Synthesis of glycerolipids containing simple linear acyl chains or aromatic rings and evaluation of their Mincle signaling activity

The synthesized glycerolipid derivatives possessing simple alkyl chains can stimulate a Mincle-mediated signaling assay relevant for the innate immune system.

The key entity of a DCAR agonist, phosphatidylinositol mannoside Ac1PIM1: its synthesis and immunomodulatory function

Ac₁PIM₁ is a potential biosynthetic intermediate for phosphatidylinositol mannosides (PIMs) from Mycobacterium tuberculosis. We achieved the first synthesis of Ac₁PIM₁ by utilizing an allyl-type protecting group strategy and regioselective phosphorylation of inositol. A very potent agonist of an innate immune receptor DCAR, which is better than previously known agonists, is demonstrated.

Synthetic studies toward citrinadin A: construction of the pentacyclic core

This manuscript describes the preparation of an advanced intermediate toward the total synthesis of citrinadin A, featuring a [3+2] cycloaddition employing in situ generation of the dipole.

Elucidating the Structural Requirement of Uridylpeptide Antibiotics for Antibacterial Activity

The synthesis and biological evaluation of analogues of uridylpeptide antibiotics were described, and the molecular interaction between the 3'-hydroxy analogue of mureidomycin A (3'-hydroxymureidomycin A) and its target enzyme, phospho-MurNAc-pentapeptide transferase (MraY), was analyzed in detail. The structure-activity relationship (SAR) involving MraY inhibition suggests that the side chain at the urea-dipeptide moiety does not affect the MraY inhibition. However, the anti-Pseudomonas aeruginosa activity is in great contrast and the urea-dipeptide motif is a key contributor. It is also suggested that the nucleoside peptide permease NppA1A2BCD is responsible for the transport of 3'-hydroxymureidomycin A into the cytoplasm. A systematic SAR analysis of the urea-dipeptide moiety of 3'-hydroxymureidomycin A was further conducted and the antibacterial activity was determined. This study provides a guide for the rational design of analogues based on uridylpeptide antibiotics.

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 10). Testicular toxicity of adriamycin observed 2 and 4 weeks after a single intravenous administration

The present study was performed to clarify whether toxic effects of the antitumor drug, adriamycin (ADR) on the male genital organ can be adequately detected 2 and 4 weeks after a single intravenous administration in the rat. ADR was intravenously administered once to 10 Crj:CD (SD) male rats/group aged 6 weeks (4-week group) and 8 weeks (2-week group) at doses of 0, 2 and 6 mg/kg. The rats were sacrificed at the age of 10 weeks. For comparison 10 rats/group were killed 2 weeks after a single intravenous administration at the age of 4 weeks (immature group). Saline was administered to control rats. Histopathological examination and a quantitative morphometry were carried out after measurement of testes weights at necropsy. In rats of the 4-week and 2-week groups, mean absolute testicular weight in all groups was significantly decreased. However, changes in mean relative weight were not evident in the 2-week group. Disappearance of seminiferous epithelial cells was observed histopathologically in rats dosed with 2 and 6 mg/kg in the 2-week group. The change was more severe in the 4-week group, when reduction of spermatogenesis and giant cells were also observed at 6 mg/kg. The quantitative morphometry in the 2-week group showed decreases in the numbers of spermatogonia and spermatocytes in stages X and XII at 2 mg/kg, and in the numbers of spermatogonia in all stages and spermatocytes in all stages except stage V at 6 mg/kg. Moreover, the numbers of spermatogonia and spermatocytes in all stages and spermatids in stages II-III and V were decreased with dose related manner in the 4-week group. In contrast, no obvious change in testes weights was apparent in the immature group. However, the numbers of spermatogonia and spermatocytes in all stages were decreased at 6 mg/kg. In conclusion, testicular toxicity of ADR could be detected 2 weeks after a single administration. Susceptibility of the testes of immature rats to ADR might be less than that of older animals.

Structural basis for plastic glycolipid recognition of the C-type lectin Mincle

Mincle (macrophage-inducible C-type lectin, CLEC4E) is a C-type lectin immune-stimulatory receptor for cord factor, trehalose dimycolate (TDM), which serves as a potent component of adjuvants. The recognition of glycolipids by Mincle, especially their lipid parts, is poorly understood. Here, we performed nuclear magnetic resonance analysis, revealing that titration of trehalose harboring a linear short acyl chain showed a chemical shift perturbation of hydrophobic residues next to the Ca-binding site. Notably, there were split signals for Tyr201 upon complex formation, indicating two binding modes for the acyl chain. In addition, most Mincle residues close to the Ca-binding site showed no observable signals, suggesting their mobility on an ∼ ms scale even after complex formation. Mutagenesis study supported two putative lipid-binding modes for branched acyl-chain TDM binding. These results provide novel insights into the plastic-binding modes of Mincle toward a wide range of glycol- and glycerol-lipids, important for rational adjuvant development.

Structure, solubility, and permeability relationships in a diverse middle molecule library

To develop methodology to predict the potential druggability of middle molecules, we examined the structure, solubility, and permeability relationships of a diverse library (HKDL ver.1) consisting of 510 molecules (359 natural product derivatives, 76 non-natural products, 46 natural products, and 29 non-natural product derivatives). The library included peptides, depsipeptides, macrolides, and lignans, and 476 of the 510 compounds had a molecular weight in the range of 500-2000 Da. The solubility and passive diffusion velocity of the middle molecules were assessed using the parallel artificial membrane permeability assay (PAMPA). Quantitative values of solubility of 471 molecules and passive diffusion velocity of 287 molecules were obtained, and their correlations with the structural features of the molecules were examined. Based on the results, we propose a method to predict the passive diffusion characteristics of middle molecules from their three-dimensional structural features.

Toward the total synthesis of luminamicin; an anaerobic antibiotic: construction of highly functionalized cis-decalin containing a bridged ether moiety

Synthesis of a cis-decalin moiety, containing an oxa-bridged cis-decalin ring system (11-oxatricyclo(5.3.1.^1,70^3,8)undecane), as a key intermediate of the total synthesis of luminamicin (1) was accomplished. One of the essential steps in our synthetic route is construction of a cis-decaline framework using a one-pot Michael addition-aldol reaction. Additionally, the bridged ether moiety was obtained by an intramolecular 1,6-oxa-Michael reaction of a conjugated aldehyde.

Synthesis and biological evaluation of a MraY selective analogue of tunicamycins

Tunicamycins, which are nucleoside natural products, inhibit both bacterial phospho-N-acetylmuraminic acid (MurNAc)-pentapeptide translocase (MraY) and human UDP-N-acetylglucosamine (GlcNAc): polyprenol phosphate translocase (GPT). The improved synthesis and detailed biological evaluation of an MraY-selective inhibitor, 2, where the GlcNAc moiety was modified to a MurNAc amide, has been described.

Pd-catalyzed Regio- and Stereoselective Hydrostannylation of an Alkyl Ethynyl Ether/One-Pot Stille Coupling Enables the Synthesis of 14-Membered Macrolactone of Luminamicin

Regio- and stereoselective hydrostannylation of alkyl ethynyl ethers generates alkenyl ethers, which are useful building blocks in organic synthesis. This efficient synthetic method, however, is limited. Here, we report not only an efficient method for a highly regio- and stereoselective Pd-catalyzed hydrostannylation of alkyl ethynyl ethers but also a scalable synthesis and construction of the core framework of luminamicin possessing all functional groups and stereocenters.

Trehalose diesters containing a polar functional group-modified lipid moiety: Synthesis and evaluation of Mincle-mediated signaling activity

Mincle, a C-type lectin receptor (CLR), activates the innate immune system by recognizing certain complex lipid compounds. In this study, we designed and synthesized trehalose disteate (TDS) and dibehenate (TDB), containing a polar-functional group in the middle of fatty acid moieties, based on a model of the Mincle-glycolipids interaction. The modified fatty acids were prepared using hydroxy fatty acids as common intermediates, and conjugated with an appropriate trehalose moiety to synthesize the desired trehalose diesters. TDE derivatives containing the modified fatty acid have different Mincle-mediated signaling activities depending on the position of the functional group and the length of the lipids. The newly developed TDE derivatives exhibit signaling activity comparable or superior to that of TDS or TDB, and the results suggest that Mincle tolerates polar functional groups at a certain position of the lipid chain of TDE. The introduction of the polar functional groups into the lipid moiety of the glycolipids also resulted in improved solubility in polar solvents, which would be advantageous for various analyses and applications.

[Evaluation for factors associated to early tracheal extubation after coronary artery bypass grafting]

Recent studies suggest that early tracheal extubation after coronary artery bypass grafting (CABG) may reduce intensive care unit use and cost. During recent two years, 96 patients were underwent CABG under cardiopulmonary bypass by low-dose fentanyl and isoflurane anesthesia. We compared two groups of patients for evaluation of factors associated to early tracheal extubation. 47 cases (Group A) were extubated within six hours (average 4.4 hrs) following operation, and 26 cases (Group B) were extubated later than twelve hours (average 57.5 hrs). It is suggested that emergency cases, female, elderly patients, dysfunction of kidney and long operation time associated to late extubation. But early extubation after CABG does not increase perioperative morbidity except for the cases that fell in low cardiac output syndrome or postoperative respiratory complications.

[Surgical treatment of coronary artery-pulmonary artery fistula with coronary aneurysm]

We experienced 4 cases of coronary artery-pulmonary artery fistula with coronary aneurysm, three patients had symptoms of chest pain, and 1 patient had cardiac murmur. Coronary arteriography showed that three patients had fistulas from the left coronary artery to the pulmonary artery; and that 1 patient had a fistula from both the right and left coronary arteries to the pulmonary artery. Moreover, 1 patient had 90% diameter stenosis of segment 7. The maximum diameter of the coronary aneurysm ranged from 12 to 20 mm (average: 15.3 mm). One patient underwent closure of the opening of the fistula, 2 patients underwent multiple ligatures of fistulas, and 1 patient underwent multiple ligatures of fistulas with coronary artery bypass grafting. The postoperative course of every patient was uneventful. There have been 42 reports on this abnormality in Japan. We should treat the fistula as early as possible to prevent cardiac complications such as myocardial ischemia and rupture of coronary aneurysm.

Correction: Synthesis of glycerolipids containing simple linear acyl chains or aromatic rings and evaluation of their Mincle signaling activity

Correction for 'Synthesis of glycerolipids containing simple linear acyl chains or aromatic rings and evaluation of their Mincle signaling activity' by Takanori Matsumaru et al., Chem. Commun., 2019, 55, 711-714, DOI: 10.1039/C8CC07322H.

Highly Selective Cytokine Induction of Nitrated Lipid-Modified α-GalCer Derivatives Demonstrating High Binding Affinity to the Lipid Antigen Presenting Molecule CD1d

Glycolipid antigens are presented by CD1d on antigen-presenting cells to T cell receptors (TCRs) of natural killer T (NKT) cells, leading to immune responses via cytokine induction. Although various lipid antigens have been found, there are only a limited number of glycolipid antigens having selective cytokine induction. In this study, we identified the glycolipids (α-GalCer nitro-type) that exhibit highly selective induction of Th2 and Th17 type cytokines, with very high binding affinity to CD1d, by introducing nature-inspired nitro-modified fatty acyl groups. The natural nitroalkene moiety of fatty acyl groups in the glycolipids effectively enhances the affinity to CD1d through presumed hydrogen-bonding and NO2-π interactions, leading to the distinctive function in cytokine induction and selectivity.