Synthesis of One Double Bond-Inserted Retinal Analogs and Their Binding Experiments with Opsins: Preparation of Novel Red-Shifted Channelrhodopsin Variants.

In optogenetics, red-shifted channelrhodopsins (ChRs) are eagerly sought. We prepared six kinds of new chromophores with one double bond inserted into the polyene side chain of retinal (A1) or 3,4-didehydroretinal (A2), and examined their binding efficiency with opsins (ReaChR and ChrimsonR). All analogs bound with opsins to afford new ChRs. Among them, A2-10ex (an extra double bond is inserted at the C10-C11 position of A2) showed the greatest red-shift in the absorption spectrum of ChrimsonR, with a maximum absorbance at 654 nm (67 nm red-shifted from that of A1-ChrimsonR). Moreover, a long-wavelength spectral boundary of A2-10ex-ChrimsonR was extended to 756 nm, which reached into the far-red region (710-850 nm).

Red-Tuning of the Channelrhodopsin Spectrum Using Long Conjugated Retinal Analogues.

As optogenetic studies become more popular, the demand for red-shifted channelrhodopsin is increasing, because blue-green light is highly scattered or absorbed by animal tissues. In this study, we developed a red-shifted channelrhodopsin by elongating the conjugated double-bond system of the native chromophore, all -trans-retinal (ATR1). Analogues of ATR1 and ATR2 (3,4-didehydro-retinal) in which an extra C═C bond is inserted at different positions (C6-C7, C10-C11, and C14-C15) were synthesized and introduced into a widely used channelrhodopsin variant, C1C2 (a chimeric protein of channelrhodopsin-1 and channelrhodopsin-2 from Chlamydomonas reinhardtii). C1C2 bearing these retinal analogues as chromophores showed broadened absorption spectra toward the long-wavelength side and photocycle intermediates similar to the conducting state of channelrhodopsin. However, the position of methyl groups on the retinal polyene chain influenced the yield of the pigment, absorption maximum, and photocycle pattern to a variable degree. The lack of a methyl group at position C9 of the analogues considerably decreased the yield of the pigment, whereas a methyl group at position C15 exhibited a large red-shift in the absorption spectra of the C1C2 analogue. Expansion of the chromophore binding pocket by mutation of aromatic residue Phe265 to Ala improved the yield of the pigment bearing elongated ATR1 analogues without a great alteration of the photocycle kinetics of C1C2. Our results show that elongation of the conjugated double-bond system of retinal is a promising strategy for improving the ability of channelrhodopsin to absorb long-wavelength light passing through the biological optical window.

Evaluation of Changes in Tumor Shadows and Microcalcifications on Mammography Following KORTUC II, a New Radiosensitization Treatment without any Surgical Procedure for Elderly Patients with Stage I and II Breast Cancer.

We introduced non-surgical therapy with a novel enzyme-targeting radiosensitization treatment, Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II) into early stages breast cancer treatment. The purpose of this study was to examine changes in tumor shadows and microcalcifications on mammography (MMG) following KORTUC II for elderly patients with breast cancer. We also sought to determine whether MMG was useful in evaluating the therapeutic effect of KORTUC II. In addition to MMG, positron emission tomography-computed tomography (PET-CT) was performed to detect both metastasis and local recurrence. In all 10 patients, tumor shadows on MMG completely disappeared in several months following the KORTUC II treatment. The concomitant microcalcifications also disappeared or markedly decreased in number. Disappearance of the tumors was also confirmed by the profile curve of tumor density on MMG following KORTUC II treatment; density fell and eventually approached that of the peripheral mammary tissue. These 10 patients have so far have also shown neither local recurrence nor distant metastasis on PET-CT with a mean follow-up period of approximately 27 months at the end of September, 2010. We conclude that breast-conservation treatment using KORTUC II, followed by aromatase inhibitor, is a promising therapeutic method for elderly patients with breast cancer, in terms of avoiding any surgical procedure. Moreover, MMG is considered to be useful for evaluating the efficacy of KORTUC II.

New radiosensitization treatment (KORTUC I) using hydrogen peroxide solution-soaked gauze bolus for unresectable and superficially exposed neoplasms.

We developed a new radiosensitization treatment using a hydrogen peroxide solution (Oxydol)-soaked gauze named KORTUC I (Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas) for superficially exposed and unresectable neoplasms, such as malignant melanoma and malignant fibrous histiocytoma (MFH), based on our experimental results which demonstrated hydrogen peroxide as a strong radiosensitizer for the highly radioresistant osteosarcoma cell line, HS-Os-1. Five patients entered our clinical trial, one of whom had unresectable malignant melanoma; one, unresectable MFH; one, unresectable extramammary Paget's disease; one, locally advanced breast cancer and one with locally recurrent skin cancer. These patients were treated with radiation therapy using a high-energy electron beam from a linear accelerator. The total dose was 48 Gy, and each fraction size was 4 Gy. Radiation therapy for these patients was performed three times per week. Each time the radiation therapy was carried out, the superficially exposed tumors of these patients were covered with hydrogen peroxide solution (Oxydol)-soaked gauze, and the lesion was gently massaged for several minutes so as to allow the hydrogen peroxide solution to soak deeply into the tumor. In the treatment results, two of these five patients showed a clinically complete response (cCR) two to three months following the end of the KORTUC I radiosensitization treatment. The other three patients showed a clinically partial response (cCR) showing a decrement of more than half of the pretreatment volume. KORTUC I was completed without any severe complications, excluding mild radiation-induced dermatitis/mucositis (Grade I). In conclusion, this newly developed radiosensitization treatment using hydrogen peroxide solution (Oxydol)-soaked gauze for superficially exposed unresectable/radioresistant neoplasms appears to be an effective and valuable method of radiosensitization in terms of the blockade of anti-oxidative enzymes such as peroxidases, resulting in local oxygen production. Moreover, the KORTUC I radiosensitization treatment is relatively inexpensive and the method can therefore be utilized worldwide for many patients suffering from superficially exposed and locally advanced radioresistant neoplasms such as malignant melanoma, malignant fibrous histiocytoma (MFH) and various types of sarcomas.

Hemorrhagic cerebral metastases from thyroid cancer on T2*-weighted gradient echo MRI.

We report a case of multiple hemorrhagic cerebral metastases from papillary thyroid cancer, with reference to T(2)*-weighted gradient echo (GRE) magnetic resonance imaging (MRI). Small metastatic nodules were recognized as round nodules with signal loss on T(2)*-weighted GRE MRI, and were more pronounced compared with other sequences. Lesions were later confirmed as hemorrhagic on T(1)- and T(2)-weighted MRI. T(2)*-weighted GRE MRI was a sensitive tool for early detection of metastases displaying hemorrhagic changes.

Pituitary stalk metastasis from breast cancer treated with systemic chemotherapy.

We describe a 61-year-old woman with diabetes insipidus caused by a pituitary stalk metastasis from breast cancer. She had a medical history of breast conservation therapy for early breast cancer 5 years previously. Pituitary, lung, liver, bone and neck lymphnode metastases was revealed at the same time. She received systemic chemotherapy consisting of docetaxel and cisplatin. After chemotherapy MRI finding in pituitary gland was improved, lung and liver metastases also improved, however, symptoms of diabetes insipidus did not improve. She is alive, receiving endocrine treatment for 2 years, since onset of diabetes insipidus.