Synthesis and bioevaluation of radioiodinated nitroimidazole hypoxia imaging agents by one-pot click reaction.

Eight radioiodinated 2-nitroimidazole derivatives for use as hypoxia imaging agents were synthesized by one-pot click reaction using four azides, two alkynes, and [131I]iodide ions and evaluated by hypoxic cellular uptake and biodistribution experiments. The results suggested that radiotracers with suitable partition coefficients (log P: -0.2-1.2) were more likely to have higher hypoxic cellular uptake. Among these eight molecules, [131I]15 ([131I]-(5-iodo-1-(2-(2-(2-nitro-1H-imidazol-1-yl)ethoxy)ethyl)-4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3-triazole)) had a suitable log P (0.05 ± 0.03) and contained two 2-nitroimidazole groups. The hypoxic/aerobic cellular uptake ratio of [131I]15 was 4.4 ± 0.5, and the tumor/blood (T/B) and tumor/muscle (T/M) ratios were 2.03 ± 0.45 and 6.82 ± 1.70, respectively. These results suggested that [131I]15 was a potential hypoxia imaging agent.

Hepatocyte miR-33a mediates mitochondrial dysfunction and hepatosteatosis by suppressing NDUFA5.

Emerging evidence suggests that microRNAs (miRNAs) are essential for metabolic haemostasis of liver tissues. Among them, miR-33a is supposed to modulate the cholesterol export and fatty acid oxidation, but whether miR-33a involves in the process of fatty liver disease is unclear. To disclose the hypothesis, we utilized miR-33a mimic and antisense to explore their effects in primary hepatocytes or high-fat diet (HFD)-fed mice. Treatment with palmitic acid (PA) or HFD significantly increased the expression of miR-33a in hepatocytes or liver tissues. In primary hepatocytes, miR-33a mimic decreased mitochondrial function, including reduction of ATP production and oxygen consumption, whereas miR-33a inhibition protected PA-induced mitochondrial dysfunction. Interestingly, miR-33a selectively suppressed mitochondrial complex I activity and protein expression, but not other complexes. Through bioinformatics prediction, we found miR-33a directly targeted on the 3'-UTR of NDUFA5. Dual-luciferase reporter analysis further confirmed the direct suppression of miR-33a on NDUFA5 expression. More importantly, administration of miR-33a antisense could effectively restore HFD-induced mitochondrial dysfunction through up-regulation of NDUFA5 levels. Mice treated with miR-33a antisense also exhibited improved liver function and structural disorders under obese status. Taken together, miR-33a was an important mediator of hepatocyte mitochondrial function, and the therapeutic benefits implied miR-33a antisense had the potential clinical application in combating the fatty liver disease.

Application study of medical robots in vascular intervention.

BACKGROUND: Based on the background of minimally invasive surgery and applications of medical robots, a vascular interventional robotic system has been developed that can be used in the field of vascular intervention. METHODS: The robotic system comprises a propulsion system, an image navigation system and a virtual surgery training system. Integration of the three systems constitutes a vascular intervention prototype robotic system used to carry out in vitro vascular intervention and animal experiments. RESULTS: On a transparent glass vascular model, a catheter was shown to enter an arbitrary branch of the vascular model with catheter motion meeting the requirements of clinical vascular intervention surgery (VIS); i.e. error band of catheter motion < 0.5 mm. In the animal experiments, 1.33-2.00 mm (4F-6F) diameter catheters were selectively inserted successfully into predefined targets in the animal, such as the renal, cardiovascular and cerebrovascular artery. Compared with conventional manual surgery, the time for robotic surgery is a little longer. There were no operative complications in the animal experiments. CONCLUSIONS: These simulation and animal study results demonstrate that this vascular interventional robotic system allows doctors to perform angiography remotely and prevents them from radiation exposure. The system may be the basis for further clinical applications of vascular intervention.

[Application value of allele frequencies in direct identification of ambiguous HLA genotypes].

This study was aimed to investigate the application value of allele frequencies in direct identification of the ambiguous HLA genotypes. The HLA-A, HLA-B and HLADRB1 loci in 658 Chinese Han donor were detected by PCR-SBT method, the ambiguous genotyping samples were identified by using high resolution PCR-SSP and heterozygous ambiguity resolution primers (HAPRs) methods. The relative probability of true genotypes was calculated by using allele frequencies and was compared with true results. The results indicated that the relative probability of true genotype > 95% in 220 HLA-A ambiguous samples, 238 HLA-B ambiguous samples and 107 HLA-DRB1 ambiguous samples were 99.5% (221/222), 95.8% (228/238) and 97.7% (104/107) respectively. As compared with phenotyping results detected by PCR-SSP and HARP methods, the matching ratios for HLA-A, HLA-B and HLA-DRB1 loci were 100% (222/222), 99.6% (237/238) and 99.1% (106/107) respectively, while the mismatch genotypes were observed only in B*3501/5501 and DRB1*1241/1504, the relative probability of them were 40.3% and 2.1% respectively. It is concluded that the detection method using allele frequencies to directly identify the ambiguous HLA genotypes in large scale PCR-SBT genotyping of donors not only can give higher accurate and reliable results, but also is a simple, rapid and cost-saving method. This method has to be used with great care in the identify-test of patient-donor pair before the transplantation.