人肝细胞色素P450 2C金属酶与药物代谢*

由于人肝细胞色素P450 2C亚家族与临床药物代谢的密切关系,其研究已引起人们的广泛关注。本文综述了四种人肝细胞色素P450 2C,着重综述了其中的三种：CYP2C9,CYP2C8,CYP2C19的研究进展。评述了CYP2C9,CYP2C8和CYP2C19的某些氨基酸残基在催化过程中的作用,这三种酶的基因多态在不同人种中的分布及药物代谢的差异,以及它们与用药的特异性及某些疾病的易感性的联系,介绍了目前提出的CYP2C8的底物药效团模型,最后总结了CYP2C9,CYP2C8,CYP2C19,CYP2C18的主要特性。     

Rapid Non‐Crosslinking Aggregation of DNA‐Functionalized Gold Nanorods and Nanotriangles for Colorimetric Single‐Nucleotide Discrimination

Gold nanoparticles modified with DNA duplexes are rapidly and spontaneously aggregated at high ionic strength. In contrast, this aggregation is greatly suppressed when the DNA duplex has a single‐base mismatch or a single‐nucleotide overhang located at the outermost surface of the particle. These colloidal features emerge irrespective of the size and composition of the particle core; however, the effects of the shape remain unexplored. Using gold nanorods and nanotriangles (nanoplatelets), we show herein that both remarkable rapidity in colloidal aggregation and extreme susceptibility to DNA structural perturbations are preserved, regardless of the shape and aspect ratio of the core. It is also demonstrated that the DNA‐modified gold nanorods and nanotriangles are applicable to naked‐eye detection of a single‐base difference in a gene model. The current study corroborates the generality of the unique colloidal properties of DNA‐functionalized nanoparticles, and thus enhances the feasibility of their practical use.     

Genotyping--from genomic DNA to genotype in a single tube

Nucleotide variations in the human genome, such as single-nucleotide polymorphisms, have been researched more intensively since it became apparent that these deviations are linked to various diseases and also several side effects of drugs. The investigation of genomic DNA in the laboratory requires routine methods that are time-, labour-, and cost-effective. These criteria are fulfilled by so-called closed-tube methods, which are applied directly to isolated genomic DNA without any preamplification.     

Arterial Blood Pressure Variability and Other Vascular Factors Contribution to the Cognitive Decline in Parkinson’s Disease

Dementia is one of the most disabling non-motor symptoms in Parkinson’s disease (PD). Unlike in Alzheimer’s disease, the vascular pathology in PD is less documented. Due to the uncertain role of commonly investigated metabolic or vascular factors, e.g., hypertension or diabetes, other factors corresponding to PD dementia have been proposed. Associated dysautonomia and dopaminergic treatment seem to have an impact on diurnal blood pressure (BP) variability, which may presumably contribute to white matter hyperintensities (WMH) development and cognitive decline. We aim to review possible vascular and metabolic factors: Renin-angiotensin-aldosterone system, vascular endothelial growth factor (VEGF), hyperhomocysteinemia (HHcy), as well as the dopaminergic treatment, in the etiopathogenesis of PD dementia. Additionally, we focus on the role of polymorphisms within the genes for catechol-O-methyltransferase (COMT), apolipoprotein E (APOE), vascular endothelial growth factor (VEGF), and for renin-angiotensin-aldosterone system components, and their contribution to cognitive decline in PD. Determining vascular risk factors and their contribution to the cognitive impairment in PD may result in screening, as well as preventive measures.     

Heat‐Triggered Crystallization of Liquid Crystalline Macrocycles Allowing for Conductance Switching through Hysteretic Thermal Phase Transitions

A polymesomorphic thermal phase‐transition of a macrocyclic amphiphile consisting of aromatic groups and oligoethylene glycol (OEG) chains is reported. The macrocyclic amphiphile exists in a highly‐ordered liquid crystal (LC) phase at room temperature. Upon heating, this macrocycle shows phase‐transition from columnar‐lamellar to nematic LC phases followed by crystallization before melting. Spectroscopic studies suggest that the thermally induced crystallization is triggered by a conformational change at the OEG chains. Interestingly, while the macrocycle returns to the columnar‐lamellar phase after cooling from the isotropic liquid, it retains the crystallinity after cooling from the thermally‐induced crystal. Thanks to this bistability, conductance switching was successfully demonstrated. A different macrocyclic amphiphile also shows an analogous phase‐transition behavior, suggesting that this molecular design is universal for developing switchable and memorizable materials, by means of hysteretic phase‐transition processes.     

Long- and short-haired Weimaraner dogs represent two populations of one breed

Weimaraners represent an old breed of hunting dogs. Today, two coat types are commonly distinguished, the more common short-hair (SH) and the long-hair (LH) variety, the latter having arisen from the SH Weimaraners. In order to analyze genetic variation in the coat varieties, we genotyped nine single nucleotide polymorphisms (SNPs) of the ABCA4 gene locus as well as six highly variable microsatellites scattered over the canine genome in the SH and LH populations. Three out of nine SNPs showed two alleles, allelic frequencies at two of these polymorphic sites differed significantly between SH and LH Weimaraners. Haplotype diversities for the three informative SNPs revealed higher estimates for the SH (0.515) than for the LH variety (0.364). In addition, two of six microsatellite markers showed significant differences in allelic frequencies between SH and LH Weimaraners. Unexpectedly, genetic diversities for all but one microsatellite were greater in LH than in SH Weimaraners. Similarly, the mean intra-individual genetic distance based on microsatellite markers was more pronounced in the LH population (0.62 for SH vs. 0.65 for LH) suggesting again closer genetic relationships among SH than LH Weimaraners. Taken together, the results of SNP analysis can be interpreted as reflections of early breed development whereas microsatellites mirror rather recent breeding strategies in the Weimaraner populations.     

Non-Alcoholic Fatty Liver Disease in Long-Term Type 2 Diabetes: Role of rs738409 PNPLA3 and rs499765 FGF21 Polymorphisms and Serum Biomarkers

Fibroblast growth factor 21 (FGF21) signaling and genetic factors are involved in non-alcoholic fatty liver disease (NAFLD) pathogenesis. However, these factors have rarely been studied in type 2 diabetes mellitus (T2D) patients from admixed populations such as in those of Brazil. Therefore, we aimed to evaluate rs738409 patanin-like phospholipase domain-containing protein (PNPLA3) and rs499765 FGF21 polymorphisms in T2D, and their association with NAFLD, liver fibrosis, and serum biomarkers (FGF21 and cytokeratin 18 levels). A total of 158 patients were included, and the frequency of NAFLD was 88.6%, which was independently associated with elevated body mass index. Significant liver fibrosis (≥F2) was detected by transient elastography (TE) in 26.8% of NAFLD patients, and was independently associated with obesity, low density lipoprotein, and gamma-glutamyl transferase (GGT). PNPLA3 GG genotype and GGT were independently associated with cirrhosis. PNPLA3 GG genotype patients had higher GGT and AST levels; PNPLA3 GG carriers had higher TE values than CG patients, and FGF21 CG genotype patients showed lower gamma-GT values than CC patients. No differences were found in serum values of FGF21 and CK18 in relation to the presence of NAFLD or liver fibrosis. The proportion of NAFLD patients with liver fibrosis was relevant in the present admixed T2D population, and was associated with PNPLA3 polymorphisms.     

Ligase chain reaction amplification for sensitive electrochemiluminescent detection of single nucleotide polymorphisms

Single nucleotide polymorphisms are the most common type of genetic variations among human beings and can serve as biomarkers for various types of diseases. In this work, based on ligase chain reaction amplification for the production of massive hemin/G-quadruplex DNAzymes to quench the electrochemiluminescent (ECL) emission of quantum dots (QDs), a universal and sensitive single nucleotide polymorphism detection method is described. During the ligase chain reaction process, the mutant K-ras target gene is recycled and exponentially duplicated, leading to the attachment of numerous G-rich sequences on the QD-embedded sensing surface. Upon the addition of the assistant sequences and hemin, numerous hemin/G-quadruplex DNAzymes are formed, which consume the dissolved oxygen in the detection buffer and result in significant quenching of QD ECL emission for sensitive single nucleotide polymorphism determination. The developed method shows a linear range of 50 fM to 50 pM and an estimated detection limit of 45 fM for the mutant K-ras gene. The proposed strategy also exhibits high selectivity towards the mutant K-ras gene against the co-existence of 10³-fold excess of the wild-type K-ras gene, which makes our method a useful addition to the alternatives for single nucleotide polymorphism monitoring.     

Fluorescence detection of single-nucleotide polymorphisms with two simple and low cost methods: a double-DNA-probe method and a bulge form method

Two 10-mer DNA probes, or one 20-mer DNA probe, respectively, hybridize with a 21-mer target DNA to form a vacancy or bulge opposite the target nucleotide. The former double-DNA-probe method and the latter bulge form method are applicable to the detection of single-nucleotide polymorphisms (SNPs). A small fluorescent dye enters into the vacancy or bulge and binds with a target nucleotide via a hydrogen bonding interaction, which causes fluorescence quenching. The interaction between fluorescent dye and the target nucleotide is confirmed by measuring the melting temperature and fluorescence spectra. The fluorescent dye, ADMND (2-amino-5,7-dimethyl-1,8-naphthyridine), is found to selectively bind with C over A or G. The methods proposed here are economic, convenient, and effective for the fluorescence detection of SNPs. Finally, the double-DNA-probe method and bulge form method are successfully applied to the detection of C/G and C/A mutations in the estrogen receptor 2 gene and progesterone receptor gene using ADMND.