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Aim Dysfunction of dopaminergic neurons in the central nervous system is considered to be related to major depressive disorder (MDD). Especially, MDD in geriatric patients is characterized by anhedonia, which is assumed to be associated with reduced dopamine neurotransmission in the reward system. Dopamine transporter (DAT) is considered to reflect the function of the dopamine nerve system. However, previous DAT imaging studies using single photon emission computed tomography or positron emission tomography (PET) have shown inconsistent results. The radioligand [18 F]FE-PE2I for PET enables more precise evaluation of DAT availability. Hence, we aimed to evaluate the DAT availability in geriatric patients with MDD using [18 F]FE-PE2I. Methods Eleven geriatric patients with severe MDD and 27 healthy controls underwent PET with [18 F]FE-PE2I, which has high affinity and selectivity for DAT. Binding potentials (BPND ) in the striatum (caudate and putamen), nucleus accumbens (NAc), and substantia nigra were calculated. BPND values were compared between MDD patients and healthy controls. Results MDD patients showed significantly lower DAT BPND in the NAc (P = 0.009), and there was a trend of lower BPND in the putamen (P = 0.032) compared to controls. Conclusion We found low DAT in the NAc and putamen in geriatric patients with severe MDD, which could be related to dysregulation of the reward system.

Electroconvulsive therapy (ECT) is an effective treatment for major depression. Previous studies suggested that dopaminergic neurotransmission plays a crucial role in the mechanism of the action of ECT. Since dopamine transporters (DAT) regulate extracellular dopamine concentration, DAT represents an interesting target for the study of the mechanism of action of ECT. Eight inpatients (7 patients with major depressive disorder and 1 patient with bipolar disorder with a DSM-IV diagnosis) received a series of 7-15(11.3±5.2) bilateral ECT sessions.The severity of symptoms was assessed using the 21-item Hamilton Depression Rating Scale (HDRS) and Clinical Global Impression-Severity (CGI-S). All patients were examined with [

Electroconvulsive therapy (ECT) is an effective treatment for major depression. Previous studies suggested that dopaminergic neurotransmission plays a crucial role in the mechanism of the action of ECT. Since dopamine transporters (DAT) regulate extracellular dopamine concentration, DAT represents an interesting target for the study of the mechanism of action of ECT. Eight inpatients (7 patients with major depressive disorder and 1 patient with bipolar disorder with a DSM-IV diagnosis) received a series of 7–15(11.3±5.2) bilateral ECT sessions.The severity of symptoms was assessed using the 21-item Hamilton Depression Rating Scale (HDRS) and Clinical Global Impression-Severity (CGI-S). All patients were examined with [18F]FE-PE2I positron emission tomography (PET) at pre-ECT, after the 10th ECT, and at post-ECT. Striatal DAT-binding potential (BPND) of all patients was reduced, with an average change ratio of DAT-BPND of -13.1±5.6%. In the 2 cases with 15 ECT sessions, the ratio change of DAT-BPND after the 15th ECT was larger than that after the 10th ECT. Also, HDRS and CGI-S were reduced. These results indicate that the dopamine nervous system is part of themechanism of action of ECT.

愛知県は，天然珪砂の全国生産量の約70％を占める日本最大の産出地であるとともに，大量の窯業副産物が排出する．現在，この副産物の処分の問題が顕在化するとともに，窯業生産への影響も年々大きくなっており，窯業副産物のリサイクルに対するニーズが高まっている．本文の実施事例では，愛知万博藤岡駐車場工事において，駐車場予定地に埋められていた微粒珪砂通称キラと同区域に廃棄されていた豆砂利を破砕·拡散混合技術により100％有効利用した．また，キラと骨材およびセメントを破砕·拡散混合することにより，都市のヒートアイランド現象対策としての「保水性舗装」と地下水の涵養，交通事故の低減の観点からの「透水性舗装」という相反する機能を同時に有するハイブリッド舗装材料を創出し，バスターミナル歩道部に採用した．