ABSTRACT
Misfolding, aggregation, and cerebral accumulation of tau deposits are hallmark features of Alzheimer's disease. Positron emission tomography study of tau can facilitate the development of anti-tau treatment. Here, we investigated a novel tau tracer 18F-PM-PBB3 (18F-APN-1607) in a mouse model of tauopathy. Dynamic PET scans were collected in groups of rTg4510 transgenic mice at 2-11 months of age. Associations between distribution volume ratios (DVR) and standardized uptake value ratios (SUVR) with cerebellum reference were used to determine the optimal scanning time and uptake pattern for each age. Immunohistochemistry staining of neurofibrillary tangles and autoradiography study was performed for ex vivo validation. An SUVR 40-70 min was most consistently correlated with DVR and was used in further analyses. Significant increased 18F-PM-PBB3 uptake in the brain cortex was found in six-month-old mice (+28.9%, p < 0.05), and increased further in the nine-month-old group (+38.8%, p < 0.01). The trend of increased SUVR value remained evident in the hippocampus and striatum regions except for cortex where uptake becomes slightly reduced in 11-month-old animals (+37.3%, p < 0.05). Radioactivity distributions from autoradiography correlate well to the presence of human tau (HT7 antibody) and hyperphosphorylated tau (antibody AT8) from the immunohistochemistry study of the adjacent brain sections. These findings supported that the 40-70 min 18F-PM-PBB3 PET scan with SUVR measurement can detect significantly increased tau deposits in a living rTg4510 transgenic mouse models as early as six-months-old. The result exhibited promising dynamic imaging capability of this novel tau tracer, and the above image characteristics should be considered in the design of longitudinal preclinical tau image studies.
Subject(s)
Benzothiazoles , Fluorodeoxyglucose F18 , Tauopathies/metabolism , tau Proteins/metabolism , Animals , Benzothiazoles/chemistry , Disease Models, Animal , Female , Immunohistochemistry , Mice , Mice, Transgenic , Molecular Structure , Positron-Emission Tomography/methods , Radioactive Tracers , Radiochemistry/methods , Tauopathies/diagnostic imaging , Tauopathies/etiology , Tauopathies/pathologyABSTRACT
OBJECTIVE: To study the feasibility of Polyvinylpolypyrrolidone (PVPP)/silicone composite automatic expanded material as implants. METHODS: The PVPP hydrogel was mixed with silicone through the location at the high temperature. Implants with different ratio of PVPP to silicone were placed under the back and nose skin in 24 New Zealand rabbits. The surrounding tissue reaction, material and skin expansion were observed and compared with those with pure silicone implants. RESULTS: The study lasted for 200 days. Compared with pure silicone implants, the composite material could expand automatically and stop expanding at about 2 weeks after implantation. Histological study showed similar inflectional and foreign body reaction around the composite material and the pure silicone. CONCLUSIONS: Compared with pure silicone, the PVPP/silicone composite implant has the advantage of automatic expansion, so as to expand the soft tissue.
Subject(s)
Biocompatible Materials , Povidone/analogs & derivatives , Prostheses and Implants , Animals , Female , Male , Materials Testing , Prosthesis Design , RabbitsABSTRACT
According to the composition of the traditional facial prosthetic adhesives, most of adhesives can be classified into two categories: acrylic polymer-based adhesive and silicone-based adhesive. In previous studies, measurements of various mechanical bond strengths were carried out, whereas the functional groups of the adhesives were evaluated seldom during the adhesion. In the present study the analysis of two facial prosthetic adhesives (Epithane and Secure Adhesive) was carried out by using infrared spectroscopy. Two adhesives in the form of fluid or semisolid were submitted to FTIR spectroscopy, respectively. The results showed that water and ammonia residue volatilized during the solidification of Epithane, and absorption peak reduction of carbonyl was due to the volatilization of acetate vinyl from Secure Adhesive. Similar silicone functional groups both in the silicone-based adhesive and in silicone elastomer could be the key to higher bond strength between silicone elastomer and skin with silicone-based adhesive. The position, shape of main absorption peaks of three adhesives didn't change, which showing that their main chemicals and basic structures didn't change during solidification.
