Cytolytic virus activation therapy and treatment monitoring for Epstein-Barr virus associated nasopharyngeal carcinoma in a mouse tumor model.

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein-Barr virus (EBV). Expression of viral proteins in the tumor cells is highly restricted. EBV reactivation by CytoLytic Virus Activation (CLVA) therapy triggers de novo expression of early viral kinases (PK and TK) and uses antiviral treatment to kill activated cells. The mechanism of tumor elimination by CLVA was analyzed in NPC mouse model using C666.1 cells. Valproic acid (VPA) was combined with gemcitabine (GCb) to stimulate EBV reactivation, followed by antiviral treatment with ganciclovir (GCV). A single cycle of CLVA treatment resulted in specific tumor cell killing as indicated by reduced tumor volume, loss of EBV-positive cells in situ, and paralleled by decreased EBV DNA levels in circulation, which was more pronounced than treatment with GCb alone. In vivo reactivation was confirmed by presence of lytic gene transcripts and proteins in tumors 6 days after GCb/VPA treatment. Virus reactivation was visualized by [124 I]-FIAU accumulation in tumors using PET-scan. This studied showed that CLVA therapy is a potent EBV-specific targeting approach for killing tumor cells. The [124 I]-FIAU appears valuable as PET tracer for studies on CLVA drug dosage and kinetics in vivo, and may find clinical application in treatment monitoring.

Sustained macrophage infiltration upon multiple intra-articular injections: an improved rat model of rheumatoid arthritis for PET guided therapy evaluation.

To widen the therapeutic window for PET guided evaluation of novel anti-RA agents, modifications were made in a rat model of rheumatoid arthritis (RA). Arthritis was induced in the right knee of Wistar rats with repeated boosting to prolong articular inflammation. The contralateral knee served as control. After immunization with methylated bovine serum albumin (mBSA) in complete Freund's adjuvant and custom Bordetella pertussis antigen, one or more intra-articular (i.a.) mBSA injections were given over time in the right knee. Serum anti-mBSA antibodies, DTH response, knee thickness, motion, and synovial macrophages were analyzed and [18F]FDG(-general inflammation) and (R)-[11C]PK11195 (macrophages-)PET was performed followed by ex vivo tissue distribution. Significant anti-mBSA levels, DTH, swelling of arthritic knee, and sustained and prolonged macrophage infiltration in synovial tissue were found, especially using multiple i.a. injections. Increased [18F]FDG and (R)-[11C]PK11195 accumulation was demonstrated in arthritic knees as compared to contralateral knees, which was confirmed in ex vivo tissue distribution studies. Boosting proved advantageous for achieving a chronic model without remission. The model will offer excellent opportunities for repeated PET studies to monitor progression of disease and efficacy of novel therapeutic agents for RA in the same animal.

The use of radiotelemetry to assess the time needed to acclimatize guineapigs following several hours of ground transport.

The objective of this study was to investigate the effect of ground transportation on guineapigs. Physiological parameters, i.e. heart rate (HR), body temperature (BT) and activity (ACT), were measured before and after transport, using previously implanted radiotelemetry transmitters. Body weight was measured before and after transport. After a postsurgical recovery period and data recording at the breeder's facility, the animals were transported for 2.25 h (Group 1) and for 7.5 h (Group 2) to a different animal facility. Data collection started immediately after arrival at the second animal facility. All parameters measured changed significantly after transport. These results suggest that a 10- to 12-day period is required for guineapigs to return to pre-transport levels of HR, BT and ACT.

Better preservation of peritoneal morphologic features and defense in rats after long-term exposure to a bicarbonate/lactate-buffered solution.

The long-term effects of a standard lactate-buffered dialysis fluid and a new, two-chamber, bicarbonate/lactate-buffered dialysis fluid (with fewer glucose degradation products and a neutral pH) were compared in an in vivo peritoneal exposure model. Rats were given daily injections, via an access port, of 10 ml of standard solution or bicarbonate/lactate-buffered solution for 9 to 10 wk. The omentum, peritoneum, and mesothelial cell layer were screened for morphologic changes. In addition, the bacterial clearing capacity of the peritoneal cells was studied. Significantly more milky spots and blood vessels were observed in the omenta of animals treated with standard solution (P < 0.03 for both parameters). Electron-microscopic analysis demonstrated dramatic changes in the appearance of the vascular endothelial cells of the milky spots and a severely damaged or even absent mesothelium on the peritoneal membrane of the standard solution-treated animals. In contrast, the mesothelium was still present in the bicarbonate/lactate-buffered solution group, although the cells lost microvilli. Both peritoneal dialysis fluids significantly increased the density of mesothelial cells (per square millimeter) on the surface of the liver and the thickness of the submesothelial extracellular matrix of the peritoneum (both P < 0.04 for both fluids versus control). A significantly better ex vivo bacterial clearing capacity was observed with peritoneal cells from the bicarbonate/lactate-buffered solution group, compared with the standard solution group (P < 0.05 in both experiments). These results demonstrate that instillation of bicarbonate/lactate-buffered solution into rats for 9 to 10 wk preserves both morphologic and immune parameters much more effectively, compared with standard solution. These findings may be of considerable clinical importance.