Synthesis of a novel series of benzocycloalkene derivatives as melatonin receptor agonists

We synthesized a novel series of benzocycloalkene derivatives and evaluated their binding affinities to melatonin receptors. To control the spatial position of the amide group, one of the important pharmacophores, we incorporated an endo double bond, an exo double bond (E- and Z-configurations), and a chiral center (R- and S-configurations) at position 1. The indan derivatives with the S-configuration at position 1 were the most promising in terms of potency and selectivity for the human melatonin receptor (MT(1) site), while compounds with the R-configuration showed little potential. Our next attempt was to investigate the most favorable conformation of the methoxy group, the other important pharmacophore for binding to the MT(1) receptor. The introduction of a methyl group at position 5 of the indene ring conserved affinity; however, at position 7, it caused a decrease in affinity. These results suggested that the substitution at position 7 forced the methoxy group to adopt an unfavorable orientation. The optimization of the condensed ring size and substituents led to (S)-8d [(S)-N-[2-(2,3-dihydro-6-methoxy-1H-inden-1-yl)ethyl]propionamide], which had high affinity for the human MT(1) receptor (K(i) = 0.041 nM) but no significant affinity for the hamster MT(3)receptor (K(i) = 3570 nM). In addition, a practical synthetic method of chiral N-[2-(2,3-dihydro-1H-inden-1-yl)ethyl]alkanamides employing asymmetric hydrogenation with (S)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl-Ru has been established.     

Monocarboxylate transporter mediates uptake of lovastatin acid in rat cultured mesangial cells

To clarify the uptake mechanism(s) for statins, we examined whether monocarboxylate transporter (MCT) contributed to the uptake of lovastatin acid by rat cultured mesangial cells. Expression of mRNAs for MCT1, 2, and 4 was confirmed in mesangial cells. The uptake of lovastatin acid by mesangial cells increased with decreasing extracellular pH. There was clear overshooting in lovastatin acid uptake by the ATP-depleted cells in the presence, but not in the absence, of an inwardly directed H(+)-gradient. The representative MCT substrates/inhibitors inhibited the lovastatin acid uptake. In particular, the inhibition of lovastatin acid uptake by L-lactic acid at the concentration of 80 mM reached 70%, and L-lactic acid and valproic acid inhibited the uptake competitively. On preloading of mesangial cells with L-lactic acid or valproic acid, the lovastatin acid uptake was significantly stimulated. The inhibition constant of L-lactic acid for the lovastatin acid uptake was 32 mM, and this value is comparable to the Michaelis constant (>20 mM) of L-lactic acid for MCT4 described elsewhere. These results demonstrate that lovastatin acid was largely taken up by mesangial cells via MCT, and suggest that MCT4 might contribute to lovastatin acid uptake in the cells.     

Simvastatin and lovastatin, but not pravastatin, interact with MDR1

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, pravastatin, was compared with simvastatin and lovastatin from the viewpoint of susceptibility to interaction with or via the multidrug transporter, MDR1 (P-glycoprotein). This was carried out using the MDR1-overexpressing cell line LLC-GA5-COL150, established by transfection of MDR1 cDNA into porcine kidney epithelial LLC-PK1 cells, and [3H]digoxin, which is a well-documented substrate for MDR1. Pravastatin, at 25-100 microM, had no effect on the transcellular transport of [3H]digoxin whereas simvastatin and lovastatin suppressed the basal-to-apical transport of [3H]digoxin and increased the apical-to-basal transport. It was suggested that recognition by MDR1 was due to the hydrophobicity. In conclusion, simvastatin and lovastatin are susceptible to interaction with or via MDR1, but pravastatin is not. This is important information when selecting the HMG-CoA reductase inhibitors for patients taking drugs that are MDR1 substrates.     

An improved method for measuring vascular permeability in rat and mouse skin

INTRODUCTION: We have improved a rodent vascular permeability measurement method employing fluorescent dye-labeled bovine serum albumin. METHODS: The incubation duration for direct fluorescent detection of skin injected with an inflammatory agent was decided based on regression curve parameters with the correlation coefficient obtained from the least squares method. RESULTS: A suitable incubation time was determined to be 2-6 h. The recovery of FITC-BSA from the skin sample was very good, and the correlation coefficient of the linear regression curve was .99. The linear relation between the previous dye extraction method using brilliant blue 6B and the new and improved fluorescence method was very high. In mice, histamine-induced serum exudation in the back skin increased from 0.31 to 1.25 microg/site in a dose-dependent manner and reached a plateau at 1.25-2.5 microg/site. The serum exudation caused by histamine increased to 10 microg/site and almost reached a plateau at 10-40 microg/site in rats. The time required for the measurement of fluorescence intensity was very short because a microplate reader was used as the measurement apparatus. CONCLUSION: The improved method is easy to use and sensitive and does not necessitate extraction of dye from the skin.     

Lack of interaction between cefdinir and calcium polycarbophil: in vitro and in vivo studies

The effect of calcium polycarbophil on the absorption of cefdinir, cephalosporin derivative, was evaluated in both in vitro and in vivo studies. In the in vitro study, the release of cefdinir from a cellulose membrane in the presence or absence of metal cations was measured using the dissolution test procedure. In the in vivo study, volunteers and a randomized crossover design with two phases were used. In the first phase, the volunteers received 200 mg of cefdinir alone (Study 1); in the other phase, they received 200 mg of cefdinir and 1200 mg of fine calcium polycarbophil granules concomitantly (Study 2). The cefdinir concentrations in the samples or serum were measured by an UV-VIS spectrophotometer or high-performance liquid chromatography. Release in the presence of iron ions was slower than that in the absence of metal ions, however no difference was observed between release in the presence of calcium ions and that in the absence of metal ions. No difference was observed in AUC(0-10), C(max) and t(max) between Study 1 and Study 2. The absorption of cefdinir was not affected by co-administration of calcium polycarbophil. Moreover, the in vitro study on the release of drugs from a cellulose membrane may predict the absorption of a drug caused by the formation of chelate complexes between the drug and metal ions.     

Differential development of cation-chloride cotransporters and Cl- homeostasis contributes to differential GABAergic actions between developing rat visual cortex and dorsal lateral geniculate nucleus

A recent study suggested that gamma-aminobutyric acid (GABA) plays differential roles in activity-dependent plasticity between the visual cortex (VC) and the dorsal lateral geniculate nucleus (dLGN). In the present study, to investigate differential GABAergic functions in postnatal visual system development, the development of [Cl(-)](i), cation-Cl(-) cotransporter expression, and the [Ca(2+)](i) responses evoked by GABA were compared between VC and dLGN during the early stages of development. Using rat brain slices from postnatal days (P) 0-17, GABA-evoked [Ca(2+)](i) responses and resting [Cl(-)](i) were measured by means of optical imaging of Ca(2+) and Cl(-), respectively. Changes in the expression of cation-Cl(-) cotransporters (viz. the outwardly-directed K(+)-Cl(-) cotransporter, KCC2, and the inwardly-directed Na(+),K(+)-2Cl(-) cotransporter, NKCC1) were examined in VC and dLGN by in situ hybridization. At birth, the excitatory actions of GABA were powerful in VC, but missing in dLGN (as indicated by neuronal [Ca(2+)](i) transients), and the resting [Cl(-)](i) was significantly higher in VC than in dLGN. Signals for KCC2 mRNA expression were significantly higher in dLGN than in VC at P0. This suggests that extrusion of Cl(-) from neurons is stronger in dLGN than in VC at P0, so that a GABAergic excitatory effect was not observed in dLGN because of more negative equilibrium potential for Cl(-). The present study indicates clear differences in the molecular and physiological bases of Cl(-) homeostasis and GABA actions between the developing VC and dLGN. Such differential GABAergic actions may underlie the distinct mechanisms involved in VC and dLGN development within the visual system.     

Generation of free radicals and/or active oxygen by light or laser irradiation of hydrogen peroxide or sodium hypochlorite

Generation of free radical and/or active oxygen by light or laser irradiation of hydrogen peroxide (H2O2) or sodium hypochlorite (NaClO), which have been used for tooth whitening or root canal irrigation, was investigated using electron spin resonance spectroscopy combined with a spin-trapping technique. When H2O2 was exposed to light or laser radiation, the amount of hydroxyl radical generated changed according to the concentration of H2O2 and irradiation time. The amount of 5,5-dimethyl-1-pyrrolidone-(2)-oxyl-(1) (DMPO-X) also changed in accordance with irradiation time. The amounts of hydroxyl radical generated from H2O2 after irradiation were in the order: plasma lamp > halogen lamp > He-Ne laser > Yellow He-Ne laser. On the other hand, the amounts of DMPO-X generated from NaClO after irradiation were in the order: plasma lamp > Yellow He-Ne laser > halogen lamp > He-Ne laser.     

Four cases of non-clostridial gas gangrene with diabetes mellitus

We report four cases of non-clostridial gas gangrene. All cases were associated with diabetes mellitus as the underlying disease. Case 1: a 60-year-old male developed an ulcerative lesion on the dorsum of his left foot. Peptostreptococcus asaccharolyticus, Citrobacter freundii and Staphyrococcus epidermidis were identified in culture from odoriferous pus. Case 2: a 81-year-old female developed a lesion on her vulva spreading to the right lower abdomen. Bacteroides bivius, Peptostreptococcus asaccharolyticus and Streptococcus faecalis were identified in culture of the odoriferous pus. Case 3: a 80-year-old male developed a swollen area with ulcer on the right foot. Bacteroides fragiris, Enterococcus faecalis, Proteus mirabilis, Enterococcus avium and Enterococcus faecalis were identified by culture. Case 4: a 52-year-old female developed swelling of her left groin. Enterococcus faecalis and Streptococcus anginosus were identified in culture from the odoriferous pus. In all patients, a radiological examination revealed the presence of subcutaneous gas in the lesion. Prognosis of non-clostridial gas gangrene is usually poor. These four patients, however, all survived. Once an infectious sign is seen in the diabetic patient, it is important to discover a gas figure by using the radiological examination (plain film or computed tomography). Earlier diagnosis and debridement are the most important for a better prognosis. Because workers with diabetes mellitus are now increasing in number, occupational physicians should always keep in mind that a serious infectious disease like non-clostridial gas gangrene can develop even from minor accidental trauma, and they should control the working environment in the workplace where accidents often happen.