Reserpine-induced rat model for depression: Behavioral, physiological and PET-based dopamine receptor availability validation.

BACKGROUND: Reserpine (RES), a Vesicular Monoamine Transporter 2 (VMAT2) inhibitor agent, has been used in preclinical research for many years to create animal models for depression and to test experimental antidepressant strategies. Nevertheless, evidence of the potential use and validity of RES as a chronic pharmacological model for depression is lacking, and there are no comprehensive studies of the behavioral effects in conjunction with molecular outcomes. METHODS: Experiment 1. Following baseline behavior testing sensitive to depression-like phenotype and locomotion (Phase 1), 27 Sprague-Dawley (SD) rats received i.p. either vehicle solution (0.0 mg/kg), low (0.2 mg/kg) or high (0.8 mg/kg) RES dose for 20 days using a pre-determined schedule and reassessed for behavioral phenotypes (Phase 2). After 10 days washout period, and a final behavioral assessment (Phase 3), the brains were collected 16 days after the last injection for mRNA-expression assessment. Experiment 2. In a similar timetable as in Experiment 1 but without the behavioral testing, 12 SD rats underwent repetitive dopamine D2/3 receptor PET scanning with [18F]DMFP following each Phase. The binding potential (BPND) of [18F]DMFP was quantified by kinetic analysis as a marker of striatal D2/3R availability. Weight and welfare were monitored throughout the study. RESULTS: Significant, dose-dependent weight loss and behavioral deficits including both motor (hypo-locomotion) and non-motor behavior (anhedonia, mild anxiety and reduced exploration) were found for both the low and high dose groups with significant decrease in D2R mRNA expression in the accumbal region for the low RES group after Phase 3. Both RES treated groups showed substantial increase in [18F]DMFP BPND (in line with dopamine depletion) during Phase 2 and 3 compared to baseline and Controls. CONCLUSIONS: The longitudinal design of the study demonstrated that chronic RES administration induced striatal dopamine depletion that persisted even after the wash-out period. However, the behavior phenotype observed were transient. The data suggest that RES administration can induce a rodent model for depression with mild face validity.

Geant4 Simulation of Gamma-Ray Transmission Buildup Factors for Human Tissues.

Quantification of scattered photons in addition to unscattered primary particles, under realistic exposure scenario, is best dealt with a parameter called "Buildup factor". The aim of this work is to simulate the transmission buildup factor (BUF) of gamma-ray in the energy range .15-15 MeV for 20 human tissues and organs using the Geant4 (version 10.5) Monte Carlo simulation followed by a geometrical progression (GP) parameterization procedure. Firstly, we verified the accuracy of Geant4 ability to predict the effective transmitted dose according to published data. Also, a comparison of simulated BUF for different geometrical configurations was carried out for some tissues and source energies. Then, we checked out the linear dependency of the K parameter (BUF is function of K) function of mean free path (mfp). Finally, we developed a fitting procedure according to GP method for BUF corresponding to 20 tissues and organs and different mfp (from 1 to 8) for energy range .15-15 MeV. We found a good agreement with previous published data. Proper comprehension of BUF for tissues leads to carefully controlling the energy absorption in the human body. Consequently, provided BUF could be of great interest for estimating safe dose levels in medical imaging and radiation therapy.

[Kaposi sarcoma in a patient with ANCA vasculitis requiring hemodialysis]. / Sarcome de kaposi compliquant une vascularite à ANCA en hémodialyse chronique.

INTRODUCTION: Iatrogenic Kaposi's sarcoma is widely reported after transplantation. Less commonly, it occurs in patients receiving immunosuppressive therapy for ANCA associated vasculitis. We report here the rare association of Kaposi's sarcoma, prurigo nodularis and ANCA associated vasculitis in a hemodialysis patient. CASE REPORT: We describe a 58-year-old woman who presented granulomatosis with polyangeiitis with alveolar hemorrhage and renal failure requiring hemodialysis. She developed cutaneous Kaposi's sarcoma seven weeks after the beginning of immunosuppressive therapy. Biological tests showed negative HHV8 virus infection. Lesions of Kaposi's sarcoma responded to a discontinuation of immunosuppressive drugs and a decreasing dosage of corticosteroids. CONCLUSION: Our case showed that the immunosuppressed state related to multiple factors such as underlying disease, immunosuppressive therapy and hemodialysis may all have contributed to the development of this neoplastic disorder in our patient.

Convenient Preparation of 18F-Labeled Peptide Probes for Potential Claudin-4 PET Imaging.

Since pancreatic cancer is often diagnosed in a late state of cancer development, diagnostic opportunities allowing early disease detection are highly sought after. As such, cancer expression of claudin proteins is markedly dysregulated, making it an attractive target for molecular imaging like positron emission tomography (PET). Claudins are a family of transmembrane proteins that have a pivotal role as members of the tight junctions. In particular, claudin-3 and claudin-4 are frequently overexpressed in pancreatic cancer. 18F-Labeled claudin selective peptides would provide access to a novel kind of imaging tools for pancreatic cancer. In this work we describe the synthesis of the first 18F-labeled probes potentially suitable for PET imaging of claudin-4 expression. These probes were prepared using oxime ligation of 5-[18F]fluoro-5-deoxyribose (5-[18F]FDR) to claudin selective peptides. As a proof-of-principle, one of them, 5-[18F]FDR-Clone 27, was isolated in >98% radiochemical purity and in 15% radiochemical yield (EOB) within 98 min, and with a molar activity of 4.0 GBq/µmol (for 30 MBq of tracer). Moreover, we present first biological data for the prepared 5-FDR-conjugates. These tracers could pave the way for an early diagnosis of pancreatic tumor, and thus improve the outcome of anticancer therapy.