1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes nigrostriatal dopaminergic neurotoxicity and behavioral impairment in rodents, and previous studies suggest that nitric oxide and reactive oxygen species are involved in MPTP-induced neurotoxicity. The present study examines the effect of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a radical scavenger, on MPTP-induced neurotoxicity in the striatum and substantia nigra pars compacta (SNc) of C57BL/6J mice. MPTP treatment (10 mg/kg s.c. ϫ 4 with 2-h intervals) decreased dopamine levels and tyrosine hydroxylase immunostaining in the striatum and SNc. Pretreatment with edaravone (1 and 3 mg/kg i.p.) significantly reduced the neurotoxicity in the SNc but not striatum. An immunohistochemical study showed that MPTP caused microglial activation both in the striatum and SNc, whereas it increased 3-nitrotyrosine immunoreactivity, an in vivo biomarker of peroxynitrite production, in the SNc but not the striatum. Furthermore, MPTP increased lipid peroxidation product thiobarbituric acid reactive substance in the midbrain, but not the striatum. Edaravone inhibited activation of the microglia and the increased 3-nitrotyrosine immunoreactivity in the SNc but not the striatum, and it also inhibited thiobarbituric acid reactive substance levels in the midbrain. Behavioral analyses showed that edaravone improved MPTP-induced impairment of locomotion and Rotorod performance. These results suggest that edaravone protects against MPTP-induced neurotoxicity in the SNc by blocking the production of reactive oxygen species or peroxynitrite and imply that dopaminergic degeneration in the SNc may play an important role in MPTP-induced motor dysfunction of mice.
Capmatinib is a highly specific, potent and selective
MET
inhibitor. This was an open‐label, multicenter, dose‐escalation, phase I study conducted in Japanese patients with advanced solid tumors (not selected based on their
MET
status). The primary objective was to determine the maximum tolerated dose (
MTD
) and/or highest studied dose being safe. Secondary objectives included safety, pharmacokinetics and preliminary antitumor activity. Dose escalation was guided by a Bayesian Logistic Regression Model dependent on dose‐limiting toxicities (
DLT
) in cycle 1. Of 44 adult Japanese patients with confirmed advanced solid tumors enrolled, 29 received capmatinib capsules (doses ranging from 100 mg once daily [q.d.] to 600 mg twice daily [b.i.d.]) and 15 received tablets (200 mg b.i.d. and 400 mg b.i.d.).
DLT
occurred in two patients: grade 2 suicidal ideation (600 mg b.i.d. capsule) and grade 3 depression (400 mg b.i.d. tablet).
MTD
was not reached. The highest studied dose determined to be safe as tablet was 400 mg b.i.d., whereas it is not yet determined for capsules. Most common adverse events suspected to be drug‐related were increased blood creatinine, nausea, decreased appetite, vomiting and diarrhea. Following repeated daily dosing up to day 15 by q.d. or b.i.d. regimen using capsules, median time to reach maximum plasma drug concentration (
T
max
) was 1.0‐4.0 hours; absorption was more rapid after dosing using tablets, with median
T
max
of 1.0 hour on both days 1 and 15. Eight patients had a best overall response of stable disease. These data support further clinical development of capmatinib.
A novel method was developed for
the synthesis of tetrazoles from
amides utilizing diphenyl phosphorazidate or bis(p-nitrophenyl) phosphorazidate as both the activator of amide–oxygen
for elimination and azide source. Various amides were converted into
the corresponding tetrazoles in good yields. This synthetic method
allows to prepare 1,5-disubstituted and 5-substituted 1H-tetrazoles from various amides without the use of toxic or explosive
reagents.
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