Can Carrier-Mediated Delivery System Promote the Development of Antisense Imaging?

PURPOSE: We aimed to explore the feasibility of transfection methods for antisense imaging. PROCEDURES: Antisense oligonucleotides (ASON) targeted to the mRNA of hTERT gene were synthesized and labeled with Technetium-99m and fluorescein isothiocyanate (FITC), respectively. Then, ASON was combined with transfection reagent Lipofectamine 2000 and Xfect(TM), named Lipo-ASON and Xfect-ASON, respectively. After transfection, the labeled ASON was characterized in hNPCs-G3 and hRPE cells. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were performed to assay the hTERT mRNA and protein levels after hNPCs-G3 cells were incubated with Lipo-ASON, Xfect-ASON, and naked ASON. In addition, Lipo-ASON, Xfect-ASON, and naked ASON were injected into tumor-bearing mice, and the biodistribution in vivo was performed. RESULTS: The presence of two transfection reagents significantly increased intracellular uptake of radiolabeled ASON in both cell lines compared with naked ASON (p < 0.05). However, there was no significant difference in cellular uptake rates of Lipo-ASON and Xfect-ASON between hNPCs-G3 and hRPE cells. In comparison with naked ASON, the fluorescence intensity was strongly enhanced after binding to transfection reagents. Furthermore, the levels of hTERT mRNA and protein were significantly reduced in cells treated with Lipo-ASON and Xfect-ASON (p < 0.05), but naked ASON had no significant effect on hTERT expression level. The biodistribution study indicated that tumor radioactivity uptake of radiolabeled ASON for naked ASON, Lipo-ASON, and Xfect-ASON group was low and shown no significant difference in vivo. CONCLUSIONS: Lipofectamine transfection and Xfect(TM) transfection were not effective delivery methods of ASON for antisense imaging.

Low- and high-frequency transcutaneous electrical acupoint stimulation induces different effects on cerebral µ-opioid receptor availability in rhesus monkeys.

Although systematic studies have demonstrated that acupuncture or electroacupuncture (EA) analgesia is based on their accelerating endogenous opioid release to activate opioid receptors and that EA of different frequencies is mediated by different opioid receptors in specific areas of the central nervous system, there is little direct, real-time evidence to confirm this in vivo. The present study was designed to investigate the effects of transcutaneous electrical acupoint stimulation (TEAS), an analogue of EA, at low and high frequencies on µ-opioid receptor (MOR) availability in the brain of rhesus monkeys. Monkeys underwent 95-min positron emission tomography (PET) with (11) C-carfentanil three times randomly while receiving 0, 2, or 100 Hz TEAS, respectively. Each TEAS was administered in the middle 30 min during the 95-min PET scan, and each session of PET and TEAS was separated by at least 2 weeks. The results revealed that 2 Hz but not 100 Hz TEAS evoked a significant increase in MOR binding potential in the anterior cingulate cortex, the caudate nucleus, the putamen, the temporal lobe, the somatosensory cortex, and the amygdala compared with 0 Hz TEAS. The effect remained after the end of TEAS in the anterior cingulate cortex and the temporal lobe. The selective increase in MOR availability in multiple brain regions related to pain and sensory processes may play a role in mediating low-frequency TEAS efficacy.

[Assessment of hepatic reserve function of cirrhosis liver using dynamic SPECT (99m)Tc-galactosyl human serum albumin scintigraphy].

OBJECTIVE: To evaluate the effectiveness of dynamic SPECT (99m)Tc-galactosyl human serum albumin (GSA) scintigraphy on the assessment of reserve function of cirrhosis liver. METHODS: From January 2010 to December 2011, 55 patients with cirrhosis liver were enrolled in this study. The case numbers of male and female were 43 and 12 respectively and the age was (51 ± 9) years (ranging from 35 to 69 years). After routine biochemistry test, CT scan and (99m)Tc-GSA dynamic SPECT scan were performed in turn using a juxtaposed SPECT/CT system. Then the morphologic volume of liver parenchyma (MLV), functional liver volume (FLV) and the hepatic cell absorption rate constant (GSA-K) were calculated. The correlations between GSA-K and routine biochemistry test, Child-Pugh score, indocyanine green clearance rate (ICG-K) were analyzed. The patients were further divided into 3 groups according to whether there was occlusion or stenosis in the main branch of left portal vein (group 1, n = 5), right portal vein (group 2, n = 13) or not (group 3, n = 37) and the regional hepatic functions index of the 3 groups were compared. RESULTS: The value of FLV of the whole, left and right liver was (594 ± 152) ml, (244 ± 119) ml and (356 ± 171) ml, respectively. There were correlations between GSA-K and total bilirubin, prothrombintime, Child-Pugh score and ICG-K (r = -0.730--0.298, P < 0.05). The FLV and MLV ratios of involved hemiliver to uninvolved hemiliver were 0.09 ± 0.06 and 0.30 ± 0.14 in group 1, 0.57 ± 0.43 and 1.08 ± 0.63 in group 2, 0.71 ± 0.30 and 0.71 ± 0.48 in group 3. The difference in MLV-FLV ratio was signifcant between group 1 and group 3, between group 2 and group 3 (P = 0.000). CONCLUSIONS: The dynamic SPCECT (99m)Tc-GSA scintigraphy can not only assess the whole liver function of cirrhosis liver effectively, but also evaluate the variation of regional liver function accurately.

Monitoring early responses to irradiation with dual-tracer micro-PET in dual-tumor bearing mice.

AIM: To monitor the early responses to irradiation in primary and metastatic colorectal cancer (CRC) with (18)F-fluorothymidine ((18)F-FLT) and (18)F-fluorodeoxyglucose ((18)F-FDG) small-animal position emission tomography (micro-PET). METHODS: The primary and metastatic CRC cell lines, SW480 and SW620, were irradiated with 5, 10 and 20 Gy. After 24 h, the cell cycle phases were analyzed. A dual-tumor-bearing mouse model of primary and metastatic cancer was established by injecting SW480 and SW620 cells into mice. micro-PET with (18)F-FLT and (18)F-FDG was performed before and 24 h after irradiation with 5, 10 and 20 Gy. The region of interest (ROI) was drawn over the tumor and background to calculate the ratio of tumor to non-tumor (T/NT) in tissues. Immunohistochemical assay and Western blotting were used to examine the levels of integrin ß(3,) Ki-67, vascular endothelial growth factor receptor 2 (VEGFR2) and heat shock protein 27 (HSP27). RESULTS: The proportion of SW480 and SW620 cells in the G(2)-M phase was decreased with an increasing radiation dose. The proportion of SW480 cells in the G(0)-G(1) phase was increased from 48.33% ± 4.55% to 87.09% ± 7.43% (P < 0.001) and that of SW620 cells in the S-phase was elevated from 43.57% ± 2.65% to 66.59% ± 7.37% (P = 0.021). In micro-PET study, with increasing dose of radiation, (18)F-FLT uptake was significantly reduced from 3.65 ± 0.51 to 2.87 ± 0.47 (P = 0.008) in SW480 tumors and from 2.22 ± 0.42 to 1.76 ± 0.45 (P = 0.026) in SW620 tumors. (18)F-FDG uptake in SW480 and SW620 tumors was reduced but not significantly (F = 0.582, P = 0.633 vs F = 0.273, P = 0.845). Dose of radiation was negatively correlated with (18)F-FLT uptake in both SW480 and SW620 tumors (r = -0.727, P = 0.004; and r = -0.664, P = 0.009). No significant correlation was found between (18)F-FDG uptake and radiation dose in SW480 or SW620 tumors. HSP27 and integrin ß(3) expression was higher in SW480 than in SW620 tumors. The T/NT ratio for (18)F-FLT uptake was positively correlated with HSP27 and integrin ß(3) expression (r = 0.924, P = 0.004; and r = 0.813, P = 0.025). CONCLUSION: (18)F-FLT is more suitable than (18)F-FDG in monitoring early responses to irradiation in both primary and metastatic lesions of colorectal cancer.