Dedicated phantom tools using traceable 68Ge/68Ga point-like sources for dedicated-breast PET and positron emission mammography scanners.

Since the early 2000s, many types of positron emission tomography (PET) scanners dedicated to breast imaging for the diagnosis of breast cancer have been introduced. However, conventional performance evaluation methods developed for whole-body PET scanners cannot be used for such devices. In this study, we developed phantom tools for evaluating the quantitative accuracy of positron emission mammography (PEM) and dedicated-breast PET (dbPET) scanners using novel traceable point-like 68Ge/68 Ga sources. The PEM phantom consisted of an acrylic cube (100 × 100 × 40 mm) and three point-like sources. The dbPET phantom comprised an acrylic cylinder (ø100 × 100 mm) and five point-like sources. These phantoms were used for evaluating the fundamental responses of clinical PEM and dbPET scanners to point-like inputs in a medium. The results showed that reasonable recovery values were obtained based on region-of-interest analyses of the reconstructed images. The developed phantoms using traceable 68Ge/68 Ga point-like sources were useful for evaluating the physical characteristics of PEM and dbPET scanners. Thus, they offer a practical, reliable, and universal measurement scheme for evaluating various types of PET scanners using common sets of sealed sources.

Effects of Shakuyaku-Kanzo-to on Extrapyramidal Symptoms During Antipsychotic Treatment: A Randomized, Open-Label Study.

Extrapyramidal symptoms (EPS) are common adverse effects of antipsychotic treatment. This study examined the effects of the traditional Japanese herbal medicine (kampo) shakuyaku-kanzo-to on EPS during antipsychotic treatment. Twenty-two Japanese patients with psychiatric disorders who had developed EPS during antipsychotic treatment were randomly allocated to receive either shakuyaku-kanzo-to (7.5 g/d) or biperiden (3 mg/d) for 2 weeks. Extrapyramidal symptoms were evaluated using the Drug-Induced Extrapyramidal Symptom Scale (DIEPSS) and the Barnes Akathisia Rating Scale. Plasma levels of the monoamine metabolite homovanillic acid and serum prolactin levels were measured to investigate the mechanisms of action of shakuyaku-kanzo-to. Twenty of the 22 patients completed the study (10 patients in the shakuyaku-kanzo-to group and 10 patients in the biperiden group). There was a time effect on the Drug-Induced Extrapyramidal Symptom Scale total score (P < 0.01), suggesting that both shakuyaku-kanzo-to and biperiden decreased EPS. Notably, there was a time × drug interaction in dystonia, suggesting that shakuyaku-kanzo-to had a greater effect on dystonia compared with biperiden. No significant changes were observed in plasma homovanillic acid or serum prolactin levels after 2 weeks of treatment in either group. The effects of shakuyaku-kanzo-to on abnormal muscle tonus and dopamine D2 receptors may have contributed to improve EPS. These results suggest that shakuyaku-kanzo-to may be useful in decreasing EPS, especially dystonia, in patients undergoing treatment with antipsychotic agents.

HIV-1 suppressive sequences are modulated by Rev transport of unspliced RNA and are required for efficient HIV-1 production.

The unspliced human immunodeficiency virus type 1 (HIV-1) RNAs are translated as Gag and Gag-Pol polyproteins or packaged as genomes into viral particles. Efficient translation is necessary before the transition to produce infective virions. The viral protein Rev exports all intron-containing viral RNAs; however, it also appears to enhance translation. Cellular microRNAs target cellular and viral mRNAs to silence their translation and enrich them at discrete cytoplasmic loci that overlap with the putative interim site of Gag and the genome. Here, we analyzed how Rev-mediated transport and the splicing status of the mRNA influenced the silencing status imposed by microRNA. Through identification and mutational analysis of the silencing sites in the HIV-1 genome, we elucidated the effect of silencing on virus production. Renilla luciferase mRNA, which contains a let-7 targeting site in its 3' untranslated region, was mediated when it was transported by Rev and not spliced, but it was either not mediated when it was spliced even in a partial way or it was Rev-independent. The silencing sites in the pol and env-nef regions of the HIV-1 genome, which were repressed in T cells and other cell lines, were Drosha-dependent and could also be modulated by Rev in an unspliced state. Mutant viruses that contained genomic mutations that reflect alterations to show more derepressive effects in the 3' untranslated region of the Renilla luciferase gene replicated more slowly than wild-type virus. These findings yield insights into the HIV-1 silencing sites that might allow the genome to avoid translational machinery and that might be utilized in coordinating virus production during initial virus replication. However, the function of Rev to modulate the silencing sites of unspliced RNAs would be advantageous for the efficient translation that is required to support protein production prior to viral packaging and particle production.