In-vitro Characterization of YM872, a Selective,Potent and Highly Water-soluble α-Amino-3-hydroxy-5-methylisoxazole-4-propionate Receptor Antagonist

The in-vitro pharmacological properties of (2,3-dioxo-7-(1H-imidazol-***1-yl)-6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl)-acetic acid monohydrate, YM872, a novel and highly water-soluble α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)-receptor antagonist were investigated. YM872 is highly water soluble (83 mg mL^?1 in Britton-Robinson buffer) compared with 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo(F)quinoxaline (NBQX), 6-(1H-imidazol-1-yl)-7-nitro-2,3(1H,4H)-quinoxalinedione hydrochloride (YM90K) or 6-cyano-7-nitroquinoxa-line-2,3-dione (CNQX). YM872 potently inhibits [³H]AMPA binding with a K_i (apparent equilibrium dissociation constant) value of 0.096 ± 0.0024 μM. However, YM872 had very low affinity for other ionotropic glutamate receptors, as measured by competition with [³H]kainate (high-affinity kainate binding site, concentration resulting in half the maximum inhibition (IC50) = 4.6 ± 0.14 μm), [³H]glutamate (N-methyl-D-aspartate (NMDA) receptor glutamate binding site, IC50 > 100 μM) and [³H]glycine (NMDA receptor glycine-binding site, IC50 > 100 μM). YM872 competitively antagonized kainate-induced currents in Xenopus laevis oocytes which express rat AMPA receptors, with a pA₂ value of 6.97 ± 0.01. In rat hippocampal primary cultures, YM872 blocked a 20-μM AMPA-induced increase of intracellular Ca²⁺ concentration with an IC50 value of 0.82 ± 0.031 μM, and blocked 300-μM kainate-induced neurotoxicity with an IC50 value of 1.02 μM. These results show that YM872 is a potent and highly water-soluble AMPA antagonist with great potential for treatment of neurodegenerative disorders such as stroke.     

Cyclic peptides

In order to explore the route for the preparation of cyclodepsipeptide by cyclization through an ester bond formation, two analogs of AM-toxin II, cyclotetradepsipeptide, were synthesized. As a preliminary experiment, synthesis of [L-Phe³, L-Ser(Bzl)⁴]-AM-toxin II, containing L-Phe and L-Ser(Bzl) in place of L-App (2-amino-5-phenyl-pentanoic acid) and ΔAla (α,β-dehydroalanine), respectively, was attempted. Cyclization of H-L-Hmb-L-Phe-L-Ser(Bzl)-L-Ala-OH in CH₂CI₂ at 10mM concentration using water-soluble carbodiimide (EDC) and 4-dimethylaminopyridine (DMAP) successfully gave a cyclic monomer in 16% yield. Cyclization of H-L-Hmb-L-App-L-Ser(Bzl)-L-Ala-OH under the same conditions also afforded a cyclic monomer, [L-Ser(Bzl)⁴]AM-toxin II, in 19% yield. Analytical parameters of these cyclic monomers obtained were identical to those of the authentic samples obtained by cyclization through a peptide bond formation.     

Prevalence of use of medically prescribed hypnotics among adult Japanese women in urban residential areas

Abstract Based on a population survey on insomnia among 3600 adult Japanese women living in urban areas, the prevalence of use of medically prescribed hypnotics is determined. The prevalence of use of medically prescribed hypnotics increases with an increase in age (<1.0% for those aged 49 or younger, while 14.3% for those aged 70 or older), in agreement with the results reported in many Western nations. The current sleep disturbance is mild in nearly half of these hypnotics users. More than one-third of the hypnotic users are receiving health care not for sleep problems but for depression, anxiety, or other reasons. More than one-third of the hypnotic users are found to be receiving hypnotics from non-psychiatrists. The percentage of this group is particularly high among those aged 60 or over, probably reflecting the fact that they are often consulting physicians for physical reasons. On the other hand, more than 80% of insomniacs are suggested to be untreated. Future public health research should focus on the quality of life and health care behaviors of untreated insomniacs and hypnotic users, especially among the elderly people, in order to assess the need for primary health care to prevent accidents, mortality, and psychiatric disorders related to sleep problems.     

PREPARATION AND PROPERTIES OF Nα-9-FLUORENYLMETHYLOXYCARBONYLAMINO ACIDS BEARING TERT.-BUTYL SIDE CHAIN PROTECTION

The preparation is described of several Nα-9-fluorenylmethyloxycarbonylamino acids and derivatives bearing tert.-butyl type side-chain protection of amine, carboxyl, guanido, hydroxyl, imidazol, and sulfhydryl functionalities. Physicochemical properties of these compounds have been determined. Cleavage of the Fmoc group by various amines appears to depend on the base strength and steric hindrance. Premature deblocking of Fmoc group by amine on solid support is very slow and may be negligible under the conditions of solid-phase synthesis.     

Hyperbaric oxygen stimulates cell proliferation and normalizes multidrug resistance protein-2 protein localization in primary rat hepatocytes

Hyperbaric oxygen therapy (HBO) has been used for many clinical treatments, including primary liver non-function. However, the cellular mechanism by which HBO treatment ameliorates liver function is not understood. Therefore, the purpose of this study was to elucidate this cellular mechanism using primary cultured rat hepatocytes in in vitro studies. Hepatocytes were treated with HBO at 1 day after plating, and the morphological and functional characteristics of bile canaliculi formed in cultured hepatocytes were observed by time-lapse microscopy. Multidrug resistance protein-2 localization was observed by confocal laser microscopy. In cultured hepatocytes, the labeling index in the HBO group at 2 days after treatment was significantly higher than that in the control group. In addition, the proliferating cellular nuclear antigen level in the HBO group was significantly higher than that in the control group. The contraction of the bile canaliculi in the HBO group was slower than in the control group and the dilatation of bile canaliculi in the HBO group was much larger than in the control group. Multidrug resistance protein-2 in the HBO group was localized at the apical membrane. These results show that HBO stimulates hepatocytes to proliferate and HBO normalizes multidrug resistance protein-2 localization to the apical membrane, which could dilate bile canaliculi.     

Cyclic peptides

Four cyclic dehydrodipeptides, cyclo (-Δaminoacyl-L-Ala-), in which aminoacyl is Phe, Apb (2-amino-4-phenylbutanoic acid), App (2-amino-5-phenylpentanoic acid) and Aph (2-amino-6-phenylhexanoic acid), were prepared by condensation of cyclo (-N-Ac-Gly-N-Ac-L-Ala-) with the corresponding aldehydes. Among them, the yield of cyclo (-ΔApb-L-Ala-) was exceptionally low. Each compound was hydrogenated in the presence of Pd black at various temperatures and chiral induction in hydrogenation was evaluated. Low chiral induction at high temperature (50d?) was observed in the case of cyclo (-ΔPhe-L-Ala-). Optically pure L-Apb, L-App and L-Aph were obtained from the corresponding cyclic dehydrodipeptides, respectively, by hydrogenation and subsequent acid hydrolysis.     

Phase I and Preliminary Phase II Studies on Aclacinomycin A in Patients with Acute Leukemia

Eight patients with acute nonlymphocytic leukemia (ANLL) andfive patients with acute lymphocytic leukemia were treated withaclacinomycin A. It was given daily by one-hour infusion indoses ranging from 0.33 to 0.70 mg/kg for seven to 20 days withoutother antileukemic agents. Two patients with ANLL achieved completeremission and one with ANLL achieved partial remission. Itsmajor toxic effects were myelosuppression and gastrointestinalsymptoms.     

Correlation of Middle Cerebral Artery Tortuosity with Successful Recanalization Using the Merci Retrieval System with or without Adjunctive Treatments

The Merci retrieval system is a useful modality for the recanalization of acute cerebral artery occlusion. However, it remains unclear whether the tortuosity of the middle cerebral artery (MCA) plays a role in successful recanalization. In this study, we investigated the association between the shape of the horizontal MCA segment (M1) and successful recanalization using the Merci retrieval system with or without adjunctive treatments. Twenty-three patients with M1 occlusion underwent thrombectomy using the Merci retrieval system with or without adjunctive treatments between July 2010 and July 2012. The anteroposterior view of final angiograms was used to measure the M1 curve angles. M1 with a curve angle measuring < 100° was defined as arch-type M1, whereas that with a curve angle measuring ≥ 100° was defined as straight-type M1. Angiographic findings were evaluated on the basis of the thrombolysis in cerebral infarction grade; grade 2B or 3 corresponds to successful recanalization. Eight patients had arch-type M1 and 15 patients had straight-type M1. Successful recanalization was achieved in 2 patients (25%) with arch-type M1 and 12 patients (80%) with straight-type M1 (p = 0.023). The mean M1 curve angle was significantly greater in the 14 patients in whom successful recanalization was achieved than in the 9 patients in whom it was not achieved (129 ± 21° vs. 93 ± 29°, p = 0.002). Arch-type M1 was an independent predictive factor of unsuccessful recanalization (odds ratio, 0.045; 95% confidence interval, 0.03–0.696). A tortuous M1 was associated with unsuccessful recanalization by the Merci retrieval system, even when adjunctive treatments were used.     

Low prevalence of hepatitis C virus infection in patients with auto-immune hepatitis type 1

Hepatitis C virus (HCV) antibodies were measured in 28 patients with auto-immune hepatitis type 1 using six different assay kits, three for C100–3 antibody and three for second generation HCV antibody, and two confirmatory tests to determine the prevalence of HCV infection in auto-immune hepatitis. These patients were confirmed to have human leucocyte antigen DR 4 or 2 which is susceptible to auto-immune hepatitis in Japanese. Of the 28 patients, four (14.3%) were positive for HCV antibody in all assays and reacted positively in at least one of the two confirmatory tests, indicating a true positive finding. Eight were positive for HCV antibody only by the Ortho ELISA kit and were negative in both confirmatory tests. The cut-off level for these results was low and became negative soon after the patients received corticosteroid treatment. Thus, these eight patients are presumed to be false-positive reactors. Hepatitis C virus RNA was detected in the serum of two of the four patients with HCV antibody and in none of 24 patients without HCV antibody. No significant difference was observed between the patients with and without HCV antibody in terms of clinical background, liver function tests and auto-antibodies. Our results showed that the prevalence of a past or present HCV infection in patients with auto-immune hepatitis in Japan is low; thus, auto-immune hepatitis is thought to be distinct from hepatitis type C. However, it is also suggested that HCV infection can potentially trigger auto-immune hepatitis.     

Epidemiology of genotypes of hepatitis C virus in Japanese patients with type C chronic liver diseases: A multi-institution analysis

Sixteen medical institutions in Japan collaborated in this study of the epidemiology of hepatitis C virus (HCV) genotypes. A total of 4176 patients with type C chronic liver disease, from the four main islands of Japan, were evaluated. Of those evaluated, 2794 had chronic hepatitis, 727 had liver cirrhosis and 655 had hepatocellular carcinoma. The HCV genotype of the patients was determined by an enzyme-linked immunosorbent assay based on serological genotype 1- and 2-specific recombinant peptides (SG-1 and SG-2, respectively) of the NS4 region. The prevalence of SG-1 and SG-2 HCV was similar in the four main islands of Japan. SG-1 HCV predominated in each disease category (69–76%). The percentage of patients with SG-1 HCV increased by 7%, while that of patients with SG-2 HCV decreased by 7%, as liver disease progressed in severity from chronic hepatitis to carcinoma (P < 0.001). Patients with either SG-1 or SG-2 had a similar mean age and history of blood transfusion. In conclusion, SG-1 HCV was found to predominate in Japan, and the HCV genotype was found to be related to the stage of hepatitis C disease.