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4. Fully non-scanning three-dimensional imaging using an all-optical Hilbert transform enabled by an optical frequency comb

Author

Kato, Takashi, Ishii, Hirotaka, Terada, Kazuhiro, Morito, Tamaki, and Minoshima, Kaoru

Subjects
Physics - Optics
Abstract

This paper demonstrates that the precise phase controllability of an optical frequency comb enables all-optical signal processing for the first time. A novel all-optical Hilbert transform is presented with precise control of relative carrier-phase and envelope of optical pulse train based on frequency control utilizing an optical frequency comb. With the proposed all-optical signal processing method, fully non-scanning one-shot three-dimensional (3D) imaging can be realized with high image resolution. The technique can be applied to coherent phase imaging simultaneously. A precise pair of 90$^\circ$-phase-shifted optical pulses over the entire spectral bandwidth can be generated based on the precise optical phase controllability of an optical frequency comb, thereby facilitating a real-time and precise all-optical Hilbert transform to obtain amplitude and phase of optical signal in a single shot of ultrashort pulses. In our experiments, we realized single-shot 3D imaging with an uncertainty of 5 $\rm{\mu}$m and obtained a surface profile with a resolution of 200 $\times$ 200 pixels., Comment: 7 pages

Published
2020

8. Primary hyperparathyroidism : minimally invasive parathyroidectomy techniques and the impact on neurocognitive and health related quality of life symptoms

Author

Ishii, Hirotaka

Subjects
616.4
Abstract

The incidence of primary hyperparathyroidism (PHPT) is rising, with an associated change in presentation. More patients are presenting with non-specific, neurocognitive and quality of life (Qol) symptoms, rather than classical symptoms of hypercalcaemia. In parallel with these changes the surgical management is also evolving. The aims of this work were to investigate current and future roles of minimally invasive parathyroidectomy (MIP) and the significance of successful parathyroidectomies on long-term nonspecific symptoms in PHPT. The United Kingdom Registry of Endocrine and Thyroid Surgeons (UKRETS) database was reviewed, and a national questionnaire performed to report on the current role and utility of MIP. A systematic review examined long-term surgical effectiveness of MIP. A case series of 140 central incision MIP (CiMIP) cases demonstrated continuing evolution of MIP and its strengths. Validated tools prospectively investigated long-term impact of parathyroidectomy on neurocognitive and QoL symptoms in 115 PHPT and 30 control patients. The UKRETS review and questionnaire revealed considerable variation in management. MIP was only performed in 50.9% of cases, but its safety and efficacy matched that of BNE in all clinical scenarios. The systematic review demonstrated excellent safety and efficacy of MIP from 5282 cases after at least one-year follow-up. Bilateral neck exploration through CiMIP cured one third of imagenegative/ non-concordant cases, demonstrating its novelty and efficacy. PHPT does negatively affect QoL compared to controls, with no association between pre-operative biochemistry and severity. Parathyroidectomy improved symptoms back to levels of controls. No pre-operative symptoms strongly predicted post-operative improvement. Frequently, certain questions scored ,extremely highly, this will improve pre-operative counselling. This work demonstrated that on a national scale, MIP is safe and effective, and this is echoed by the systematic review. Image-negative/non-concordant cases are difficult to manage, but CiMIP proves it can be done both safely and effectively. Successful parathyroidectomy does improve debilitating nonspecific symptoms, which should then be considered as indications for surgery.

Published
2019

9. Low-noise 750-MHz spaced Yb:fiber frequency combs

Author

Ma, Yuxuan, Xu, Bo, Ishii, Hirotaka, Meng, Fei, Nakajima, Yoshiaki, Matsushima, Isao, Schibli, Thomas R., Zhang, Zhigang, and Minoshima, Kaoru

Subjects
Physics - Instrumentation and Detectors, Physics - Optics
Abstract

We demonstrate two fully and tightly phase locked 750 MHz ytterbium (Yb) fiber frequency combs that are independently stabilized to a continuous wave (CW) laser with <1 rad RMS phase error. A bulk EOM and a single stack PZT are separately utilized as the fast actuators for cavity length stabilization. The carrier envelop frequencies are phase locked by single loop feedback to laser diode current, showing 1.6 MHz servo bumps. The in-loop fractional frequency instabilities are ~1.5e-18 at 1s for both combs. To the best of our knowledge, this is the highest repetition rate in fiber based low phase noise combs tightly locked to optical frequency reference., Comment: 4 pages, 5 figures, 1 table

Published
2018
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18. Chronic estradiol exposure suppresses luteinizing hormone surge without affecting kisspeptin neurons and estrogen receptor alpha in anteroventral periventricular nucleus†

Author

Kunimura, Yuyu, Iwata, Kinuyo, Ishii, Hirotaka, and Ozawa, Hitoshi

Abstract

Mammalian ovulation is induced by a luteinizing hormone surge, which is triggered by elevated plasma estrogen levels; however, chronic exposure to high levels of estradiol is known to inhibit luteinizing hormone secretion. In the present study, we hypothesized that the inhibition of the luteinizing hormone surge by chronic estradiol exposure is due to the downregulation of the estrogen receptor alpha in kisspeptin neurons at hypothalamic anteroventral periventricular nucleus, which is known as the gonadotropin-releasing hormone/luteinizing hormone surge generator. Animals exposed to estradiol for 2 days showed an luteinizing hormone surge, whereas those exposed for 14 days showed a significant suppression of luteinizing hormone. Chronic estradiol exposure did not affect the number of kisspeptin neurons and the percentage of kisspeptin neurons with estrogen receptor alpha or c-Fos in anteroventral periventricular nucleus, but it did affect the number of kisspeptin neurons in arcuate nucleus. Furthermore, chronic estradiol exposure did not affect gonadotropin-releasing hormone neurons. In the pituitary, 14-day estradiol exposure significantly reduced the expression of LhbmRNA and LHβ-immunoreactive areas. Gonadotropin-releasing hormone-induced luteinizing hormone release was also reduced significantly by 14-day estradiol exposure. We revealed that the suppression of an luteinizing hormone surge by chronic estradiol exposure was induced in association with the significant reduction in kisspeptin neurons in arcuate nucleus, luteinizing hormone expression in the pituitary, and pituitary responsiveness to gonadotropin-releasing hormone, and this was not caused by changes in the estrogen receptor alpha-expressing kisspeptin neurons in anteroventral periventricular nucleus and gonadotropin-releasing hormone neurons, which are responsible for estradiol positive feedback.Suppression of luteinizing hormone surge by chronic estradiol exposure was induced in association with alterations of arcuate nucleus kisspeptin, pituitary luteinizing hormone, and pituitary responsiveness and was not caused by the changes in anteroventral periventricular nucleus kisspeptin neurons, which are responsible for estradiol positive feedback.Graphical Abstract

Published
2024
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34. Identification of Novel C-Terminally Truncated Estrogen Receptor β Variant Transcripts and Their Distribution in Humans

Author

Ishii, Hirotaka, Hattori, Yujiro, Ozawa, Hitoshi, Hirotaka, Ishii, Yujiro, Hattori, and Hitoshi, Ozawa

Subjects
Male, Transcription, Genetic, Biology, 03 medical and health sciences, Exon, 0302 clinical medicine, Complementary DNA, Testis, Estrogen Receptor beta, Humans, Tissue Distribution, RNA, Messenger, Gene, Genomic organization, Genetics, Base Sequence, Alternative splicing, Brain, Genetic Variation, General Medicine, Exons, Nuclear receptor, 030220 oncology & carcinogenesis, RNA splicing, 030211 gastroenterology & hepatology, Human genome
Abstract

Background The nuclear receptor genes, including estrogen receptor β (ERβ), contain non-conventional internal and terminal exons, and alternative choice of the exons yields multiple mRNA and protein variants with unique structures and functions. However, the genomic structure of the intronic and 3'-downstream regions of the human ERβ gene and the presence of novel ERβ variants with non-conventional sequences have not been re-examined in about 20 years. Therefore, we attempted to re-characterize the structure of the human ERβ gene and identify novel non-conventional exons and distinct splice variants. Methods Rapid amplification of cDNA 3'-end and RT-PCR cloning were used to isolate human ERβ mRNA variants from the testis. The identified cDNA sequences were mapped on the human genome assembly. Expression profiles of the variants were assessed by RT-PCR analysis. Results We cloned multiple ERβ mRNA variants with novel nucleotide sequences from the testis and identified several alternative splice sites, 3'-elongation of conventional coding exons, and novel terminal exons in the human ERβ gene. The variants encode C-terminally truncated ERβ proteins termed ERβ6, ERβ7, ERβEx. 4L, and ERβEx. 6L. Furthermore, we identified exon 7-defective forms of ERβ2/βcx, ERβ4, ERβ6, and ERβ7. Subsequently, we noted distinct expression patterns of the variants in human peripheral organs and brain subregions. Conclusion This study clarified complicated genomic organization and splicing patterns of the human ERβ gene that contribute to the distinct heterogeneity of human ERβ mRNAs and proteins.

Published
2020

35. Local production of sex hormones and their modulation of hippocampal synaptic plasticity

Author

Ishii, Hirotaka, Tsurugizawa, Tomokazu, Ogiue-Ikeda, Mari, Asashima, Makoto, Mukai, Hideo, Murakami, Gen, Hojo, Yasushi, Kimoto, Tetsuya, and Kawato, Suguru

Subjects
Hippocampus (Brain) -- Chemical properties -- Research, Dehydroepiandrosterone -- Research, Hormones, Sex -- Research -- Chemical properties, Psychology and mental health, Chemical properties, Research
Abstract

It is believed that sex hormones are synthesized in the gonads and reach the brain via the blood circulation. In contrast with this view, the authors have demonstrated that sex [...]

Published
2007

48. Subunit profiling and functional characteristics of acetylcholine receptors in GT1-7 cells

Author

Arai, Yuki, Ishii, Hirotaka, Kobayashi, Makito, and Ozawa, Hitoshi

Subjects
Thermo Fisher Scientific Inc., Scientific equipment and supplies industry, Cyclic adenylic acid, Pituitary hormones, Psychology and mental health
Abstract

GnRH neurons form a final common pathway for the central regulation of reproduction. Although the involvement of acetylcholine in GnRH secretion has been reported, direct effects of acetylcholine and expression profiles of acetylcholine receptors (AChRs) still remain to be studied. Using immortalized GnRH neurons (GT1-7 cells), we analyzed molecular expression and functionality of AChRs. Expression of the mRNAs were identified in the order [alpha]7 > [beta]2 = [beta]1 ⧠[alpha]4 ⧠[alpha]5 = [beta]4 = [delta] > [alpha]3 for nicotinic acetylcholine receptor (nAChR) subunits and m4 > m2 for muscarinic acetylcholine receptor (mAChR) subtypes. Furthermore, this study revealed that [alpha]7 nAChRs contributed to Ca.sup.2+ influx and GnRH release and that m2 and m4 mAChRs inhibited forskolin-induced cAMP production and isobutylmethylxanthine-induced GnRH secretion. These findings demonstrate the molecular profiles of AChRs, which directly contribute to GnRH secretion in GT1-7 cells, and provide one possible regulatory action of acetylcholine in GnRH neurons. Keywords: Acetylcholine, Acetylcholine receptors, Gonadotropin-releasing hormone, GnRH neurons, GT1-7, Author(s): Yuki Arai[sup.1,2], Hirotaka Ishii[sup.1], Makito Kobayashi[sup.2] and Hitoshi Ozawa[sup.1] Introduction Acetylcholine is the first neurotransmitter identified in the nervous systems and plays pivotal roles in a wide variety of [...]

Published
2016
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