Centrin controls the activity of the ciliary reversal-coupled voltage-gated Ca2+ channels Ca2+-dependently

In Paramecium, ciliary reversal is coupled with voltage-gated Ca2+ channels on the ciliary membrane. Wepreviously isolated a P. caudatum mutant, cnrC, with a malfunction of the Ca2+ channels and discovered thatthe channel activity of cnrC was restored by transfection of the P. caudatum centrin (Pccentrin1p) gene, whichencodes a member of the Ca2+-binding EF-hand protein family. In this study, we injected various mutatedPccentrin1p genes into cnrC and investigated whether these genes restore the Ca2+ channel activity of cnrC. APccentrin1p mutant gene lacking Ca2+ sensitivity of the third and fourth EF-hands lost the ability to restore thechannel function of cnrC, and mutation of the fourth EF-hand caused more serious impairment than mutation ofthe third EF-hand. Moreover, a Pccentrin1p gene lacking the N-terminal 34-amino acid sequence also lost theability to restore the channel activity. Native-PAGE analysis demonstrated that the N-terminal sequence isimportant for the Ca2+-dependent structural change of Pccentrin1p. These results demonstrate that Pccentrin1pCa2+-dependently regulates the Ca2+ channel activity in vivo

Uniform Silica Coated Fluorescent Nanoparticles: Synthetic Method, Improved Light Stability and Application to Visualize Lymph Network Tracer

BACKGROUND: The sentinel lymph node biopsy (SLNB) was developed as a new modality in the surgical diagnosis of lymph node metastases. Dye and radioisotope are major tracers for the detection of sentinel lymph nodes (SLN). Dye tends to excessively infiltrate into the interstitium due to their small size (less than several nanometers), resulting in difficulties in maintaining clear surgical fields. Radioisotopes are available in limited number of hospitals. Fluorescent nanoparticles are good candidates for SLN tracer to solve these problems, as we can choose suitable particle size and fluorescence wavelength of near-infrared. However, the use of nanoparticles faces safety issues, and many attempts have been performed by giving insulating coats on nanoparticles. In addition, the preparation of the uniform insulating layer is important to decrease variations in the quality as an SLN tracer. METHODOLOGY/PRINCIPAL FINDINGS: We herein succeeded in coating fluorescent polystyrene nanoparticles of 40 nm with uniform silica layer of 13 nm by the modified Stöber method. The light stability of silica coated nanoparticles was 1.3-fold greater than noncoated nanoparticles. The popliteal lymph node could be visualized by the silica coated nanoparticles with injection in the rat feet. CONCLUSIONS/SIGNIFICANCE: The silica coated nanoparticles in lymph nodes could be observed by transmission electron microscope, suggesting that our silica coating method is useful as a SLN tracer with highly precise distribution of nanoparticles in histological evaluation. We also demonstrated for the first time that a prolonged enhancement of SLN is caused by the phagocytosis of fluorescent nanoparticles by both macrophages and dendritic cells

Imaging Processes Using Core-Shell Particle Colloid Solutions for Medical Diagnosis

This paper describes our studies on development of methods for preparing colloid solutions of core-shell particles composed of core of materials with imaging ability and shell of silica that is inert to living bodies, and on their imaging properties. The methods for silica-coating are based on hydrolysis and condensation of silicone alkoxide in the presence of particles. AgI nanoparticles fabricated by mixing AgClO 4 aqueous solution with KI aqueous solution were silica-coated with an aid of silane coupling agent. The silica-coated AgI particle colloid solution revealed X-ray imaging ability. Au nanoparticles, which were produced with reduction of HAuCl 4 using citrate as reducing reagent and then surface-modified with silane coupling agent, were coated with silica. Images of the colloid solution were successfully taken through X-ray irradiation. For Gd compound, silica nanoparticles fabricated by a Stöber method were coated with Gd compound shell by a homogeneous precipitation method, and then coated with silica shell. The colloid solution was successfully imaged through magnetic resonance. Commerciallyavailable Cd-related semiconductor nanoparticles were surfacemodified with silane coupling agent, and then coated with silica. Tissues of mouse were imaged by injecting their colloid solution and using an in vivo fluorescence imaging system (IVIS)

Clinical Significance of ABCG2/BCRP Quantified by Fluorescent Nanoparticles in Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy

Breast cancer resistance protein (BCRP), also known as ATP-binding cassette transporter G2 (ABCG2), is associated with chemotherapy resistance. BCRP is also implicated in breast cancer stem cells, and is reported as a poor prognostic factor. However, the relationship of BCRP levels in breast cancer tissues with chemotherapy resistance and prognosis has not been clarified. We aimed to evaluate the correlation between BCRP expression and prognosis in breast cancer using immunohistochemistry with fluorescent phosphor-integrated dots (IHC-PIDs). A total of 37 breast cancer patients with residual cancer in the primary tumor and axillary lymph nodes were evaluated. BCRP levels in breast cancer tissue and metastatic lymph nodes were quantitatively detected after neoadjuvant chemotherapy (NAC). Among these 37 patients, 24 had corresponding core needle biopsies obtained before NAC. Biomarker assay with IHC-PIDs showed high accuracy for the quantitative assessment of BCRP with low expression. High BCRP expression in the primary tumor and metastatic lymph nodes after preoperative chemotherapy was associated with worse overall survival. In conclusion, high BCRP levels may be associated with poor prognosis in patients with breast cancer, having residual tumors within the primary tumor and lymph nodes after preoperative chemotherapy. These findings provide a basis for further appropriate adjuvant therapy in these patients