Autopsy and postmortem examination case study on genetic risk factors for cardiac death: polymorphisms of endothelial nitric oxide synthase gene Glu298Asp variant and T-786C mutation, human paraoxonase 1 (PON1) gene and alpha2beta-adrenergic receptor gene

BACKGROUND/AIM: The Glu298Asp variant in exon 7 and T-786C mutation in the 5'-flanking region of the endothelial nitric oxide synthase (eNOS) gene, paraoxonase I gene (PON1), and alpha2beta-adrenergic receptor gene (alpha2beta-AR) have been reported to be genetic risk factors for coronary heart disease (CHD). The aim of this study was to investige the effects of these four genetic polymorphisms on the probability of death due to CHD, using data obtained from medico-legal autopsies. METHODS: Blood samples from three groups: healthy controls, dead cases with CHD and without CHD (the latter as a control for dead cases) were used. After DNA extraction, genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test. RESULTS: The frequency of the T allele in Glu298Asp variant in the dead cases with CHD was significantly higher than that in the healthy control (p < 0.001, OR = 4.47) and that in the dead cases without CHD (p < 0.001, OR = 7.62). The gene frequency of PON1 was significandy different (p = 0.007) between dead cases with and without CHD, and was also significantly different (p = 0.025) between the healthy control and dead cases without CHD. The gene frequency of PON1 was not significantly different (p = 0.401) between the healthy controls and dead cases with CHD. Hence this gene was not associated with death due to CHD. The other polymorphisms (T-786C mutation, alpha2beta-AR) also showed no effect on death due to CHD. CONCLUSION: The polymorphism of Glu298Asp eNOS gene in dead cases may be useful for determining the cause of death in CHD cases in the Japanese population.     

6-Chloro-3-(((1-[11C]methyl)-2-(S)-pyrrolidinyl)methoxy)-5-(2-fluoropyridin-4-yl)pyridine ([11C]JHU85270), a potent ligand for nicotinic acetylcholine receptor imaging by positron emission tomography.

6-Chloro-3-((1-methyl)-2-(S)-pyrrolidinyl)methoxy)-5-(2-fluoropyridin-4-yl)pyridine (JHU85270), a novel high-affinity ligand for the alpha4beta2 nicotine acetylcholine receptor (nAChR) (K(i)=86, 115 pM; K(i)(JHU85270)/K(i)(epibatidine)=1.7) with a log D(7.4)=1.6 was synthesized in 56% overall yield. [(11)C]JHU85270 was synthesized from [(11)C]-methyl iodide and the corresponding normethyl precursor. The average time of radiosynthesis, purification, and formulation was 37 min from the end of bombardment. The average radiochemical yield of [(11)C]JHU85270 was 37%+/-3% (non-decay corrected). The average specific radioactivity was 398+/-165 GBq/micromol (10750+/-4468 mCi/micromol) and the radiochemical purity was greater than 99%.     

Preparation and biological evaluation of 2-amino-6-[18F]fluoro-9-(4-hydroxy-3-hydroxy-methylbutyl) purine (6-[18F]FPCV) as a novel PET probe for imaging HSV1-tk reporter gene expression

INTRODUCTION: 2-Amino-6-[(18)F]fluoro-9-(4-hydroxy-3-hydroxy-methylbutyl) purine (6-[(18)F]FPCV) was prepared via a one-step nucleophilic substitution and evaluated as a novel probe for imaging the expression of herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene. METHODS: Log P of 6-[(18)F]FPCV was calculated in octanol/phosphate-buffered saline (PBS). Stability studies were performed in PBS and bovine serum albumin (BSA). Cell uptake was performed at various time points in wild-type cells and transduced cells. For in vivo studies, tumors were grown in nude mice by inoculation with C6 cells, wild type and tk positive. The radiotracer was intravenously injected to animals, and micro-PET imaging was performed. Biodistribution of 6-[(18)F]FPCV was performed on another group of animals at different time points. RESULTS: Log P of 6-[(18)F]FPCV was -0.517. 6-[(18)F]FPCV was fairly stable in PBS and BSA at 6 h. The tracer uptake in C6-tk cells was 5.5-18.8 times higher than that in wild-type cells. The plasma half-life of 6-[(18)F]FPCV was as follows: alpha t(1/2)=1.2 min and beta t(1/2)=73.7 min. The average ratio of tumor uptake between the transduced tumor and the wild-type tumor was 1.69 at 15 min. CONCLUSION: Biological evaluation showed that 6-[(18)F]FPCV is a potential probe for imaging HSV1-tk gene expression. However, its in vivo defluorination may limit its application in PET imaging of gene expression.     

Preliminary evaluation of 2-[4-[3-tert-butylamino)-2-hydroxypropoxy]phenyl]-3-methyl-6-me thoxy-4(3H)-quinazolinone ([+/-]HX-CH 44) as a selective beta1-adrenoceptor ligand for PET

(+/-)-3-[11C]Methyl-2-[4-[3-(tert-butylamino)-2-hydroxypropoxy]phenyl]-6 -methoxy-4(3H) quinazolinone ([+/-]-[11C]HX-CH 44) was labeled with carbon-11 using [11C]iodomethane with the corresponding N-demethylated precursor. Then, 30-90 mCi (1.10-3.33 GBq) of pure [11C]HX-CH 44 were obtained 30 min after end of bombardment with specific radioactivities of 500-1,400 mCi/micromol (18.5-51.8 GBq/micromol). Myocardial uptake in dogs was 0.340+/-0.043 pmol/mL tissue per nanomole injected, 10-15 min postinjection. Heart-to-lung ratio was 3 from the 5th to the 30th minute. Only 35% of the myocardial radioactivity could be displaced. Tissue uptake could not be blocked with appropriate compounds. Therefore, (+/-)-[11C]HX-CH 44 does not appear to be a suitable ligand for the study of myocardial beta1-adrenoceptors in positron emission tomography.     

Synthesis and evaluation of 6-[11C]methoxy-3-[2-[1-(phenylmethyl)-4-piperidinyl]ethyl]-1,2- benzisoxazole as an in vivo radioligand for acetylcholinesterase

6-Methoxy-3-[2-[1-(phenylmethyl)-4-piperidinyl]ethyl]-1,2-benzisoxazole is a high affinity (K(i) = 8.2 nM) reversible inhibitor of acetylcholinesterase (AChE). The carbon-11 labeled form was prepared in high (>97%) radiochemical purity and with specific activities of 37+/-20 GBq/micromol at end of synthesis, by the alkylation of the desmethyl precursor with [11C]methyl trifluoromethanesulfonate in N,N-dimethyl-formamide at room temperature. In vivo studies in mice demonstrated good blood brain permeability but essentially uniform regional brain distribution. Thus, despite in vitro and in vivo activity as an AChE inhibitor, 6-[11C]methoxy-3-[2-[1-(phenylmethyl)-4-piperidinyl]ethyl]-1,2-benzis oxa zole does not appear to be a good candidate for in vivo imaging studies of AChE in the mammalian brain.