5-Hydroxy-2-methylpyridine Isolated from Cigarette Smoke Condensate Aggravates Collagen-Induced Arthritis in Mice.

The risk of rheumatoid arthritis (RA) is linked to environmental and genetic factors. Cigarette smoking is an established environmental risk factor for the disease that contributes to its development and severity. Previously, we found that cigarette smoke condensate (CSC), both mainstream and sidestream, aggravates collagen type II-induced arthritis (CIA), which was observed following either intraperitoneal inoculation or nasal exposure.

Kinetic and molecular orbital analyses of dicarboxylic acylcarnitine methylesterification show that derivatization may affect the screening of newborns by tandem mass spectrometry.

Newborns are routinely screened for organic acidemias by acylcarnitine analysis. We previously reported the partial catalytic methylesterification of dicarboxylic acylcarnitines by benzenesulfonic acid moiety in the solid extraction cartridge during extraction from serum. Since the diagnosis of organic acidemias by tandem mass spectrometry is affected by the higher molecular weight of these derivatized acylcarnitines, we investigated the methylesterification conditions.

A new quadruple hydrogen-bonding module based on five-membered heterocyclic urea structure.

N,N'-Di-4-triazolylurea (DTU) has developed as a new ADDA module and DTU forms a stable ADDA*DAAD heterocomplex with 2,7-diamido-1,8-naphthyridine (DAN) (K(s) = 2.6 x 10(5) M(-1) in CHCl(3)). The K(s) value of the complex between DTU and DAN is 100-fold greater than that of the complex between N,N'-di-2-pyridylurea and DAN due to replacement of a pyridine ring with a 1,2,3-triazole ring.

A new quadruple hydrogen-bonding module with a DDAA array: formation of a stable homodimer without competition from undesired hydrogen-bonded dimers.

A new DDAA hydrogen-bonding module (UImp-2), based on a ureidoimidazo[1,2-a]pyrimidine structure, forms a highly stable homodimer (K(dim) > 1.1 x 10(5) M(-1) in CDCl(3)) without competition from undesired hydrogen-bonded dimers.

The effects of O-substituents of hexahomotrioxacalix[3]arene on potentiometric discrimination between dopamine and biological organic/inorganic cations.

As an interesting type of molecular recognition at a membrane surface, the tri-O-acetic acid ester (host 2) of hexahomotrioxacalix[3]arene, when incorporated into poly(vinyl chloride) (PVC) liquid membranes, displays a high potentiometric selectivity for dopamine over, not only other catecholamines (noradrenaline, adrenaline), but also quaternary ammonium guests (tetramethylammonium, choline, and acetylcholine) and inorganic cations (Na+, K+, NH4+). Interestingly, changes in membrane potential based on the host-guest complexation of host 2 that were observed dopamine/inorganic cation selectivity were not displayed by the related hosts 3 and 4, which contain amide substituents. This paper describes our efforts to separately estimate the two factors contributing to the dopamine selectivities, i.

Dopamine-selective potentiometric responses by new ditopic sensory elements based on a hexahomotrioxacalix[3]arene.

New ditopic sensory elements 2 and 3 for catecholamines based on a hexahomotrioxacalix[3]arene, with a boronic acid substituent appended, were designed and synthesized. As an interesting mode of molecular recognition at membrane surfaces, the host, when incorporated into poly(vinyl chloride) (PVC) liquid membranes, displayed excellent potentiometric selectivity for dopamine over other catecholamines (noradrenaline and adrenaline) and inorganic cations (Na+, K+, and NH4+).

Highly selective recognition of adenine nucleobases by synthetic hosts with a linked five-six-five-membered triheteroaromatic structure and the application to potentiometric sensing of the adenine nucleotide.

A new structure for an adenine-selective host molecule, featuring the pertinent link of five-six-five-membered heteroaromatic rings and two carbamoyl NH sites, was developed. This structure provides a correctly oriented array of complementary hydrogen bonding sites for the adenine nucleobase, which exploits both Watson-Crick and Hoogsteen-type interactions. The complexation with adenine nucleobases by multiple hydrogen bonding was supported by (1)H NMR spectroscopy.

New lignan glycosides from Chinese medicinal plant, Sinopodophillum emodi.

Two new podophillotoxin glucosides, L-picropodophillotpxin 7'-O-(beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside) (2) and L-picropodophillotpxin 7'-O-beta-D-glucopyranoside (3), were isolated from Chinese medicinal plant, Sinopodophillum emodi, together with 4 known compounds, podophillotoxin (1), podorhizol 4'-O-beta-D-glucopyranoside (4), deoxypodophillotoxin (5), and dehydropodophillotoxin (6). The structures of 2 and 3 were finally determined by the extensive decouping and nuclear Overhauser effect (NOE) experiments in NMR spectra and circular dichroism (CD) spectra. Compound 2 is the second example of podophillotoxin diglucoside, and both the first one and 2 were isolated from S.

Rearrangement of 2-Benzocycloammonium N-Methylides.

2-Methyl-2-[(trimethylsilyl)methyl]-2,3,4,5,6,7-hexahydro-1H-2-benzazoninium iodide (9), 2-methyl-2-[(trimethylsilyl)methyl]-1,2,3,4,5,6-hexahydro-2-benzazocinium iodide (15), and 2-methyl-2-[(trimethylsilyl)methyl]-2,3,4,5-tetrahydro-1H-2-benzazepinium iodide (23) exist as mixtures of two stable conformational isomers (types A and B) in an aprotic solvent at room temperature. The corresponding conformational isomers of N-methylides 10A,B, 16A,B, and 24A,B were generated by fluoride ion-induced desilylation, and their rearrangement was investigated. Type A ylides gave [2,3] sigmatropic rearrangement products (isotoluenes) 11, 17, 18, and 27, while type B ylides gave Stevens rearrangement products 8, 20, and 29 via radical-cleavage and -recombination pathways.