Shortest Double-Walled Carbon Nanotubes Composed of Cycloparaphenylenes

Invited for this month's cover is the group of Prof. Dr. Shigeru Yamago at the Kyoto University (Japan). The image shows the host-guest possibilities of cycloparaphenylenes (CPPs) of different sizes. Size selective interaction between [n]CPP and [n+5]CPP affords a host-guest complex, [n+5]CPP⊃[n]CPP, which is the shortest double-walled armchair carbon nanotube. The size-selective complex formation illustrates the importance of van der Waals interactions. A ternary complex, [15]CPP⊃[10]CPP⊃C₆₀ , also forms from [15]CPP, [10]CPP, and C₆₀ . Read the full text of the article at 10.1002/cplu.201700097.

Shortest Double-Walled Carbon Nanotubes Composed of Cycloparaphenylenes

The host-guest chemistry of cycloparaphenylenes (CPPs) of different sizes is described. [n]CPPs (n=5, 6, 7, 8, and 10) selectively interact with [n+5]CPPs, forming complexes [n+5]CPP⊃[n]CPP, which are the shortest double-walled armchair carbon nanotubes. The size selectivity is dictated by the difference in diameters of the CPPs (that is, 0.34-0.35 nm), which maximizes attractive van der Waals interactions. Theoretical calculations suggest that the orbital energies of the CPPs become perturbed upon complex formation, and orbital mixing between the two CPPs is predicted for large CPP pairs. The association constants in 1,1,2,2-[D₂ ]tetrachloroethane, estimated by ¹ H NMR titration, are approximately 10³  mol L^-1 at 50 °C. Van't Hoff plot analysis reveals that complexation is driven mainly by entropy owing to desolvation of the CPPs. [13]CPP also forms a complex with [4]cyclo-2,7-pyrenylene ([4]CPY), which is a π-extended [8]CPP. Theoretical calculations suggest that the formation of [13]CPP⊃[4]CPY is more exothermic than that of [13]CPP⊃[8]CPP. A ternary complex, [15]CPP⊃[10]CPP⊃C₆₀ , is also formed by mixing [15]CPP and [10]CPP⊃C₆₀ .

Phosphinoselenothioic Acids and Their Salts: Synthesis, Characterization, and Reaction with Electrophiles

[reaction: see text] Phosphinoselenothioic acid ammonium salts were synthesized in good yields by reacting phosphinoselenothioic acid S-[2-(trimethylsilyl)ethyl] esters with ammonium fluorides. Phosphinoselenothioic acid alkali metal salts were obtained as 18-crown-6 ether complexes with high efficiency by treating the esters with alkali metal fluorides and 18-crown-6 ether. The salts were stable under air and soluble in water. The structures of the phosphinoselenothioic acid tetramethylammonium salt and P-methylseleno-P-methylthiophosphonium triflate were determined by X-ray molecular structure analyses. These salts exhibited monomeric structures, and the central phosphorus atoms adopted tetrahedral structures. Alkylation of the ammonium salts selectively gave phosphinoselenothioic acid Se-alkyl esters, whereas acylation of the salts preferentially gave S-acyl products. Protonation of the salts selectively gave the phosphinoselenothioic S-acid. The S-acid generated in situ was reacted with alpha,beta-unsaturated carbonyl compounds and cyclohexene oxide to give the adducts. Molecular orbital calculations were carried out for the model compound H2P(Se)S- to elucidate the electronic structure.

Degranulation of eosinophils mediated by intercellular adhesion molecule-1 and its ligands is involved in adhesion molecule expression on endothelial cells-selective induction of VCAM-1

BACKGROUND

Adhesion molecules and eosinophils may play an important role in the pathogenesis of allergic inflammatory reactions.

OBJECTIVE

We attempted to clarify eosinophil activation, such as degranulation, by signaling through adhesion molecule and to determine whether degranulation is involved in adhesion molecule expression on endothelial cells.

METHODS

Eosinophils were cultured with or without recombinant soluble intercellular adhesion molecule-1 (ICAM-1), and the levels of eosinophil cationic protein and eosinophil-derived neurotoxin were determined. The influence of these eosinophil granule proteins or supernatant from eosinophil cultured with ICAM-1 on the expression of ICAM-1 or vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells was also examined by flow-cytometric analysis.

RESULTS

Supernatant levels of eosinophil granule protein were significantly increased by culture for 4 hourss or 16 hours with recombinant soluble ICAM-1, suggesting degranulation by adherence to ICAM-1. Both granule proteins and the supernatants of eosinophils cultured with recombinant soluble ICAM-1 induced expression of ICAM-1 and VCAM-1 on endothelial cells, with the latter showing a more prominant increase.

CONCLUSION

Degranulation mediated through adherence to endothelial cells by ICAM-1 and its ligands may be involved in the expression of adhesion molecules, such as ICAM-1 or VCAM-1, on these cells. Our finding of the selective induction of VCAM-1 expression suggests that eosinophil adherence to endothelial cells, even if it is because of ICAM-1, may be involved in selective eosinophil recruitment and accumulation at sites of allergic inflammation.

Priming effect of RANTES on eosinophil oxidative metabolism

BACKGROUND

RANTES has been shown to possess chemotactic activity for eosinophils, which have also been considered to play a role in allergic inflammation through reactive oxygen species. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils.

METHODS

Purified eosinophils by CD16-negative selection or an eosinophilic cell line (EoL-1) were incubated with or without RANTES (2.5 x 10(-6) M). To the mixture of eosinophils and luminol, calcium ionophore (A23187) or opsonized zymosan (OZ) was added, and radical oxygen products were determined by luminol-dependent chemiluminescence for 600 s.

RESULTS

Eosinophil-mediated radical oxygen products of untreated eosinophils produced with A23187 gave a peak value of 14.09 +/- 2.40 (mean +/- SE, n = 12) relative light units (RLU) and an integrated value of 3232.20 +/- 513.09 RLU. However, with treatment with RANTES, a peak value of 18.66 +/- 2.40 RLU and an integrated value of 5301.05 +/- 561.02 RLU were obtained. Eosinophil oxidative metabolism-induced A23187 or OZ was apparently augmented by the preincubation with RANTES. In addition, the radical oxygen products of EoL-1 showed similar results.

CONCLUSIONS

Thus, we concluded that RANTES may play an important role in the pathogenesis of allergic inflammation through its involvement in eosinophil activation, as evidenced by oxygen products, as well as in selective eosinophil infiltration as selective eosinophil chemoattractant.

Inhibitory effect of ibudilast (KC-404) on the expression of the beta2 integrin family on an eosinophilic cell line (EoL-1)

BACKGROUND

Adhesion molecules are thought to play a key role in inflammatory processes in bronchial asthma. We previously observed an increased expression of the beta2-integrin family on an eosinophilic cell line (EoL-1) by platelet-activating factor (PAF).

OBJECTIVE

In the present study, we examined the effect of ibudilast (KC-404), a novel anti-asthma agent, on beta2 integrin expression induced by PAF.

MATERIAL AND METHODS

EoL-1 cells (1x10(6)/mL) were incubated in the presence or absence of 10(-6) M ibudilast (KC-404), then cells were cultured in the presence or absence of PAF (10(-7) M) for 45 minutes. Flow cytometric analysis for CD11a, CD11b, and CD18 expression was examined.

RESULTS

Ibudilast had an inhibitory effect on beta2 integrin expression induced by PAF [CD11a: 84.8% versus 73.1% (preincubation with ibudilast), CD11b: 35.8% versus 26.2%, CD18 74.9% versus 65.6%].

CONCLUSIONS

Ibudilast (KC-404) has anti-inflammatory activities through its inhibitory effect on the expression of adhesion molecules on eosinophils.

Elevated local production of neopterin from alveolar macrophages in patients with internal lung diseases

1. We measured the neopterin level in the supernatant of cultured alveolar macrophages from patients with interstitial lung diseases (ILD patients) as a marker for the activation of alveolar macrophage. 2. In ILD patients, the supernatant neopterin level (40.1 +/- 7.8 pmol/ml) was significantly higher (P < 0.01) than that in control subjects (10.0 +/- 1.6 pmol/ml). 3. We also found that macrophage-colony stimulating factor (M-CSF) and interleukin-2 (IL-2) augmented neopterin production from alveolar macrophage in both ILD patients (51.6 +/- 10.4 and 60.1 +/- 10.8 pmol/ml, respectively, P < 0.01) and control subjects (28.1 +/- 6.0 and 25.7 +/- 4.9 pmol/ml, respectively). 4. These findings suggest that alveolar macrophages produce neopterin by M-CSF or IL-2.

Possible involvement of mononuclear cells stimulated with specific allergen from asthmatic patients in ICAM-1 expression on the eosinophilic cell line

Adhesion molecules, particularly intercellular adhesion molecule-1 (ICAM-1), recently have been considered to play a key role in inflammatory processes in asthma. Thus, from the point of view of cell interactions between mononuclear cells and eosinophils, we examined whether the supernatant of mononuclear cells (MNC) obtained from mite-allergic asthmatic patients cultured with specific allergen is involved in ICAM-1 expression using an eosinophilic cell line (EoL). ICAM-1 expression was induced by the supernatant of MNC from mite-allergic asthmatic patients stimulated with mite allergen as well as by a combination of IL-3, GM-CSF, and IL-5. Thus, we could conclude that some cytokines produced by specific allergen-stimulated MNC in asthmatics might be involved in allergic inflammation through the induction of adhesion molecule expression such as ICAM-1 on eosinophils in asthma or allergic disorders.

Adhesion to fibronectin augments eosinophil radical oxygen products

Fibronectin, an extracellular matrix component, is a ligand for very late activation antigen (VLA)-4, which is one of the beta 1-integrin family of molecules expressed by eosinophils. This study examined the effect of adherence to fibronectin on radical oxygen products from eosinophils. Adhesion of eosinophils to fibronectin resulted in enhancement of eosinophil production of radical oxygen species, as determined by luminol-dependent chemiluminescence of eosinophils stimulated with calcium ionophore. It was concluded that eosinophil adhesion to extracellular matrix via adhesion molecules may be important in the pathogenesis of allergic inflammation through eosinophil activation.

Increased eosinophil oxidative metabolism by treatment with soluble intercellular adhesion molecule-1

Adhesion molecules may play an important role not only in adherence of inflammatory cells (particularly eosinophils) to an inflamed focus but also in activation of these cells. It is therefore of interest to evaluate eosinophil activation via intercellular adhesion molecule-1 (ICAM-1) and the beta 2-integrin family, namely CR3 (Mac-1), lymphocyte function-associated antigen (LFA)-1 alpha and LFA-1 beta, which are ligands for ICAM-1. Reactive oxygen species generated by eosinophils have also been considered capable of causing airway injury at the inflamed focus. This study examined the effect of recombinant soluble ICAM-1 and its ligands on eosinophil-induced radical oxygen products in terms of luminol-dependent chemiluminescence. Recombinant soluble ICAM-1 augmented eosinophil oxidative metabolism. It was concluded that signaling via adhesion molecules might play an important role in the pathogenesis of allergic inflammation through activation of eosinophils, e.g. an increase in oxidative metabolism.

Possible release of eosinophil granule proteins in response to signaling from intercellular adhesion molecule-1 and its ligands

The presence of a large variety of membrane receptors and the identification of cytotoxic molecules (mainly granule basic proteins) have indicated that eosinophils should br considered as effector cells. It has recently been suggested that adhesion molecules, particularly intercellular adhesion molecule-1 (ICAM-1), play an important role in allergic inflammation, for example in bronchial asthma. This study therefore investigated the possible release of granule protein in response to signaling from ICAM-1 and its ligands. The concentrations of eosinophil cationic protein and eosinophil-derived neurotoxin in supernatants of eosinophils were significantly greater (p < 0.05) in the presence of recombinant soluble ICAM-1 than without it. These results suggest that signaling from ICAM-1 and its ligands might induce eosinophil activation and might be involved in degranulation of eosinophil granule proteins, e.g. eosinophil cationic protein and eosinophil-derived neurotoxin.

Effect of RANTES on intracellular expression of EG2 antigen in eosinophils

RANTES, which is released from thrombin-stimulated platelets, is a member of the 8-kDa cytokine family that has been shown to possess chemotactic activity for eosinophils. The effect of RANTES on the intracellular expression of EG2 antigen in eosinophils was examined in this study. RANTES augmented the intracellular expression of EG2 antigen in eosinophils. These findings suggest that RANTES not only modulates the chemotactic activity of eosinophils but also intensifies the function of eosinophil activation.

A comparative study of eosinophil isolation by different procedures of CD16-negative depletion

Eosinophils were isolated by the three methods of CD16-negative depletion: 1) magnetic beads, 2) fluorescence-activated cell sorter (FACS), and 3) complement reaction. Their purity, yield, and viability were compared. The second procedure produced well purity and viability (94.65 +/- 1.51% and 94.98 +/- 1.40%, respectively) but low yield of eosinophils (65.47 +/- 2.47%). The viability of cells obtained by the third procedure was not efficient (80.83 +/- 2.85%), while the purity and the yield were efficient (96.23 +/- 1.09% and 90.75 +/- 1.72%, respectively). In conclusion, the magnetic beads method (purity: 98.02 +/- 0.45%, yield: 91.05 +/- 2.43%, viability: 97.57 +/- 0.37%) was the most advantageous of these three procedures. Moreover, in the functional assay, radical oxygen products from eosinophils isolated by the procedure with complement reaction were less than with the magnetic beads or FACS procedures.

Induction of beta 2 integrin expression on an eosinophilic cell line (EoL-1) by the supernatant of mononuclear cells stimulated with specific allergen from asthmatic patients

Adhesion molecules recently have been considered to play an important role in inflammatory processes in bronchial asthma. Our previous study revealed high expression of beta 2-integrin family (CR3, LFA-1 alpha, CD18) on hypodense eosinophils. Thus, from the point of view of cell-to-cell interaction between mononuclear cells and eosinophils, we examined whether the supernatant of mononuclear cells obtained from mite-allergic asthmatic patients cultured with specific allergen mite-allergen is involved in adhesion molecule expression using an eosinophilic cell line (EoL-1). These characteristics of beta 2-integrin family expression (high expression of beta 2 integrin) were induced by the supernatant of mononuclear cells from mite-allergic asthmatic patients stimulated with mite-allergen as well as with a combination of the recombinant eosinophilopoietic growth cytokines (IL-3, GM-CSF and IL-5). Thus, we could conclude that some cytokines produced by specific allergen stimulated mononuclear cells in asthmatics might be involved in allergic inflammation through the induction of adhesion molecule expression on eosinophils in asthma or allergic disorders.

[Effect of platelet-activating factor (PAF) on eosinophil adhesion to plasma-coated glass using eosinophilic cell lines (EoL-1, EoL-3)]

Adhesion molecules on various inflammatory cells, especially on eosinophils are now considered to play an important role in allergic inflammations such as bronchial asthma. In this study, we examined the effect of platelet-activating factor (PAF) on eosinophil adhesion to plasma-coated glass using eosinophilic cell lines (EoL-1, EoL-3), since PAF might be an important mediator as an eosinophil chemotactic agent in bronchial asthma. PAF markedly augmented adherence to plasma-coated plates. This finding suggests that PAF might up-regulate the inflammatory reaction in bronchial asthma through its action as an augmentative agent for eosinophil adhesion as well as its action as an eosinophil chemotactic agent.

Characteristics of bone marrow cells of patients with eosinophilic pneumonia

Bone marrow features were studied to clarify the pathogenesis of peripheral blood eosinophilia in eosinophilic pneumonia. We observed (1) increases in the number of nucleated cells in patients with this disease as compared with that of control subjects (205,944 +/- 104,253 versus 118,154 +/- 76,306) (P < .05); (2) increases in the myelocyte to erythrocyte ratio (6.95 +/- 4.06 versus 4.02 +/- 1.36) (P < .05) mainly due to a marked increase in the eosinophilic series; and (3) an increase in the eosinophilic series with advance in the maturation process, the degree of increase becoming greater with the increase in eosinophilic maturation. These findings suggest that differentiation and maturation of the precursor cells into mature eosinophils were accelerated in the bone marrow in eosinophilic pneumonia by some lymphokines as eosinophilopoietic growth factors.

Induction of expression of adhesion molecules on an eosinophilic cell line (EoL-1) by the supernatant of lymphocytes stimulated with specific allergen from asthmatic patients

Recently, adhesion molecules have been considered to play an important role in inflammatory processes in bronchial asthma. To extend our understanding of the high-intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-1 beta, ICAM-1) on hypodense eosinophils, which was observed in our previous study, we examined whether the supernatant of lymphocytes from mite-allergic asthmatic patients is involved in adhesion molecule expression using an eosinophilic cell line (EoL-1). These characteristics of adhesion molecule expression were induced by the supernatant of lymphocytes obtained from mite-allergic asthmatic patients cultured with specific allergen as well as a combination of recombinant cytokines (IL-3, GM-CSF, IL-5). Thus, we could conclude that some lymphokines produced by specific allergen in asthma might be involved in the high-intensity expression of adhesion molecules on hypodense eosinophils in asthma or allergic disorders.

Effect of platelet-activating factor and platelet factor 4 on eosinophil adhesion

The effect of platelet-activating factor (PAF) and platelet factor 4 (PF4) on the adhesion of isolated human eosinophils or eosinophilic cell lines (EoL-1, EoL-3) was examined. Both PAF and PF4 augmented eosinophil adhesion to plates coated with AB plasma or recombinant soluble intercellular adhesion molecule-1 (r-sICAM-1). These findings suggest that PAF and PF4 not only modulate chemotactic activity of eosinophils but also intensify the function of eosinophil adhesion. Since PAF and PF4 induce the expression of adhesion molecules (LFA-1 alpha, LFA-1 beta, CR3) on eosinophils, we could conclude that PAF or PF4 are closely related to eosinophil accumulation not only as chemotactic agents but also as augmentative agents for eosinophil adhesion through involvement in functional eosinophil adherence as well as surface expression of adhesion molecules on eosinophils.

RANTES augments radical oxygen products from eosinophils

RANTES, which is released from thrombin-stimulated platelets, is a member of the 8-kD cytokine family that has been shown to possess chemotactic activity for eosinophils. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils. RANTES treatment resulted in the enhancement of peak value and integrated value of productivity of eosinophil-mediated radical oxygen products determined by luminol-dependent chemiluminescence of EoL-3 cells stimulated with A23187. In addition, the radical oxygen products of EoL-1 or eosinophils showed similar results. Thus, we could conclude that platelets might play an important role in the pathogenesis of allergic inflammation through the involvement in the selective eosinophil infiltration and eosinophil activation by releasing RANTES.

Possible induction of intercellular adhesion molecule-1 (ICAM-1) expression on endothelial cells by platelet-activating factor (PAF)

We demonstrated that PAF and IL-1 markedly induce ICAM-1 expression on endothelial cells. These findings suggest that PAF not only modulates inflammation by the attraction and activation of eosinophils or by platelet activation, but also intensifies such phenomena by induction of ICAM-1 expression on endothelial cells.