Retrieval of the conductivity spectrum of tissuesin vitrowith novel multimodal tomography.

OBJECTIVE: Imaging of tissue engineered three-dimensional (3D) specimens is challenging due to their thickness. We propose a novel multimodal imaging technique to obtain multi-physical 3D images and the electrical conductivity spectrum of tissue engineered specimensin vitro. APPROACH: We combine simultaneous recording of rotational multifrequency electrical impedance tomography (R-mfEIT) with optical projection tomography (OPT). Structural details of the specimen provided by OPT are used here as geometrical priors for R-mfEIT. MAIN RESULTS: This data fusion enables accurate retrieval of the conductivity spectrum of the specimen. We demonstrate experimentally the feasibility of the proposed technique using a potato phantom, adipose and liver tissues, and stem cells in biomaterial spheroids. The results indicate that the proposed technique can distinguish between viable and dead tissues and detect the presence of stem cells. SIGNIFICANCE: This technique is expected to become a valuable tool for monitoring tissue engineered specimens' growth and viabilityin vitro.

The hepatic lipase gene C-480T polymorphism in the development of early coronary atherosclerosis: the Helsinki Sudden Death Study.

BACKGROUND: The T allele of the hepatic lipase (HL) C-480T polymorphism was previously found to be associated with lower post-heparin plasma HL activity, atherosclerosis and risk of coronary artery disease. We studied the association of HL C-480T polymorphism with the extent of atherosclerosis at vessel-wall level in an autopsy series of middle-aged men. MATERIALS AND METHODS: An autopsy cohort of 700 Caucasian Finnish men aged 33-70 years (mean 53 years), which comprised two autopsy series, collected 10 years apart during 1981-82 and 1991-92, were analysed. Areas of coronary wall covered with fatty streaks and fibrotic and complicated lesions were measured using computer-assisted planimetry and related to HL C-480T genotypes (CC, CT, and TT). RESULTS: There was a significant age-by-genotype interaction on the mean percentage area of fatty streaks (P = 0.01). The HL C-480T polymorphism was a significant explanatory factor for fatty streak area in men under 53 years of age with or without age, body mass index, hypertension, diabetes, smoking, alcohol consumption, apolipoprotein E genotype, and series number as covariates. Men carrying the TT genotype had two times larger areas of fatty streaks compared to the CC carriers (8.8% vs. 4.3%, P = 0.009). However, this association disappeared in men over 53 years. The areas of more advanced atherosclerotic lesions did not vary significantly among the genotype groups. CONCLUSIONS: Our results suggest that the HL C-480T polymorphism affects the formation of early coronary atherosclerotic lesions in men in their early middle age.

Toll-like receptor 4 polymorphism is associated with coronary stenosis but not with the occurrence of acute or old myocardial infarctions.

OBJECTIVE: Atherosclerosis is considered to be a chronic inflammatory disease. Toll-like receptor 4 (TLR-4), a key mediator in activating inflammatory cascade, has an A-to-G functional polymorphism that changes aspartic acid to glycine at position 299. TLR-4 is activated by, for example, lipopolysaccharides. The purpose of this study was to investigate the role of a common Asp299Gly polymorphism of the TLR-4 gene in atherosclerosis. MATERIAL AND METHODS: The study comprised autopsy material from 657 men (the Helsinki Sudden Death Study; mean age 53, range 33-70 years). RESULTS: Fewer G-allele carriers had 3-vessel coronary artery disease compared with AA homozygotes (OR 0.32; 95 % CI, 0.12-0.88, p = 0.027), and they also had a lower mean value for maximal coronary stenosis (p = 0.019). TLR-4 polymorphism was not significantly associated with the occurrence of acute or old myocardial infarction (MI). CONCLUSIONS: The G allele of the TLR-4 gene, which is associated with a lower inflammation response, was associated with a lower risk of coronary stenosis but not with the occurrence of MI and hence is not a major factor in the development of coronary atherosclerosis.