Imaging polarimetry of the circularly polarizing cuticle of scarab beetles (Coleoptera: Rutelidae, Cetoniidae)

The light reflected from the metallic-shiny regions of the cuticle of certain beetles belonging to the Scarabaeoidea is known since 1911 to be left-handed circularly polarized. Only photographs of a few selected species of scarabs, taken through left- and right-circular polarizers, have earlier been published. Through a right-circular polarizer these beetles appear more or less dark. This demonstration is, however, inadequate to quantitatively investigate the spatial distribution and the wavelength dependency of the circular polarization of light reflected from the scarab cuticle. In order to overcome this problem, we have developed a portable, rotating analyzer, linear/circular, digital, and imaging polarimeter. We describe here our polarimetric technique and present for the first time the linear and circular polarization patterns of the scarab species Chrysophora chrysochlora, Plusiotis resplendens (Rutelidae), and Cetonischema jousselini (Cetoniidae) in the red (650 nm), green (550 nm), and blue (450 nm) parts of the spectrum. We found the wavelength- and species-dependent circular polarization patterns in scarabs to be of a rather complex nature. These patterns are worthy of further studies.     

Orthogonal polarization spectral imaging--a new clinical method for monitoring of microcirculation

The orthogonal polarization spectral (OPS) imaging technology is a new non-invasive method to directly visualize multiple conditions of the microcirculation which has several clinical applications in humans. Quantitative measurement of the diameter of vessels, the velocity of red blood cells and functional capillary density (FCD) can be made. Activation of leukocytes can be monitored and also quantified. A transdermal approach can be used in premature babies and neonates to view the microcirculation and has also been used experimentally to determine haemoglobin levels. The application to various surfaces and solid organs allows a variety of pathophysiologies and phases to be examined.     

Polarized expression of drug transporters in differentiated human hepatoma HepaRG cells

The HepaRG cell line is a well-differentiated human hepatoma cell line proposed as a surrogate for human hepatocytes, especially for hepatic detoxification studies. Polarized status of drug transporters, i.e., their coordinated location at sinusoidal or canalicular membranes, which represents a key hallmark of hepato-biliary drug transport, remains however incompletely documented in HepaRG cells. The present study was therefore designed to analyze transporter location in HepaRG cells, which exhibit mRNA expressions of most of hepatic transporters. HepaRG cells were demonstrated, through immunofluorescence staining, to express several drug transporters at their sinusoidal pole, especially the influx transporters organic anion transporting polypeptide (OATP) 1B1, OATP2B1 and organic cation transporter (OCT) 1 and the efflux transporter multidrug resistance-associated protein (MRP) 3. In addition, the efflux transporters P-glycoprotein and MRP2 were detected at the canalicular pole of HepaRG cells. Moreover, saturable uptake of reference substrates for the sinusoidal transporters sodium-taurocholate cotransporting polypeptide, OATPs and OCT1 and canalicular secretion of reference substrates for the efflux transporters bile salt export pump and MRP2 were observed. This polarized and functional expression of various sinusoidal and canalicular transporters in HepaRG cells highlights the interest of using these hepatoma cells in xenobiotic transport studies.     

Micromorphological and micronanalytical characterization of stagnating and progressing root caries lesions

Root caries is the predominant disease of the tooth tissues in the elderly population and differs in progression and micromorphology from coronal dentin caries. Therefore, different clinical concepts are needed for the treatment of these progressing and arrested lesions. It was the aim of this study to investigate the three-dimensional structure and volume of stagnating and progressing root caries lesions and to determine the mineral composition of the different lesion zones to achieve a better understanding of the natural history of root caries lesion formation. Of 21 extracted human teeth of patients between 42 and 77 years of age with stagnating and progressing root caries lesions serial sections were cut and investigated with polarized light and scanning electron microscopy. From the polarized light micrographs 3D reconstructions were made to determine the volumes of the lesion zones and their relations expressed in a demineralization index (DI). With increasing size of the demineralizing zone the DI increased indicating an increase in the size of the translucent zone. The 3D reconstructions showed distinct differences between stagnating and progressing root caries lesions. In the hypermineralized translucent dentin not all dentin tubules were obliterated by intratubular dentin and within the translucent dentin scattered dead tracts were found. Electron dispersive X-ray (EDX) analysis showed that the intertubular dentin of the translucent dentin was also demineralized to a certain extent. The results indicate distinct morphological differences between progressing and stagnating root caries lesions which may have consequences for treatment strategies.     

巨噬细胞的研究进展

巨噬细胞在固有免疫、适应性免疫、组织重构与损伤组织修复过程中起关键作用。有关巨噬细胞的研究受到极大关注,近年来在巨噬细胞起源、极化等方面都取得了许多新的研究进展,证实了组织固有巨噬细胞起源于胚胎干细胞以外的卵黄囊,组织巨噬细胞可原位增殖,并相继发现了M2a、M2b．M2c、M2d、M2r及非M1非M2巨噬细胞亚型,同时对巨噬细胞的极化及各亚型的功能及其在某些疾病发生、发展与转归中的作用有了新的认识。     

含氟环境对烤瓷金属耐腐蚀性能的影响

目的：研究分析氟离子环境对经烤瓷工序处理后金属耐腐蚀性能的影响。方法：制作金（Au）合金、纯钛（Ti）、钴铬（CoCr）合金、镍铬（NiCr）合金试件各6件,模拟临床烤瓷处理后分别置于人工唾液（A组）,含有0.2% NaF的人工唾液中（B组）,绘制极化曲线,获得并分析材料的自腐蚀电位和腐蚀电流密度。结果：B组与A组比较,镍铬合金、钴铬合金、纯钛自腐蚀电位负值增大,差异有统计学意义（P〈0.05）,金合金无差异。同种金属B组与A组相比腐蚀电流密度增加,差异有统计学意义（P〈0.05）。结论：氟离子环境能使得烤瓷处理过金属的耐腐蚀性能下降,腐蚀速度加快。金合金与纯钛耐腐蚀性能较强,其次是CoCr合金,NiCr合金最差。     

等离子渗氮和镀膜复合处理对氟环境中纯钛耐腐蚀性能的影响

目的：观察等离子渗氮和磁控溅射镀膜复合处理对氟环境中纯钛铸件耐腐蚀性能的影响。方法：用动电位极化技术测试对照组和复合处理组纯钛铸件在氟质量浓度为1000mg/L的人工唾液中的自腐蚀电流密度和自腐蚀电位,扫描电镜观察试件表面形貌,能谱分析腐蚀面的微量元素,对结果进行分析比较。结果：对照组和复合处理组纯钛铸件在氟离子1000mg/L的人工唾液中的自腐蚀电流密度分别为（3101.58±245.07）nA和（8.60±0.45）nA,自腐蚀电位分别为（-0.50±0.11）V和（-0.20±0.02）V。复合表面处理后纯钛铸件的自腐蚀电流密度明显减小（P〈0.01）,自腐蚀电位明显大（P〈0.01）。扫描电镜显示,复合处理后纯钛铸件较对照组纯钛铸件的表面腐蚀形貌明显减轻,对照组纯钛铸件腐蚀面发现氟元素而复合处理组未发现氟元素。结论：等离子渗氮和磁控溅射镀膜复合处理能明显提高纯钛铸件的耐腐蚀性。     

极化镁液加环磷腺苷葡胺治疗顽固性心衰的临床观察

目的：探讨极化镁液加环磷腺苷葡胺注射液治疗顽固性心力衰竭（心衰）的临床疗效。方法：将我院65例顽固性心衰患者随机分为治疗组32例、对照组33例。对照组给予常规抗心衰治疗并联合应用极化镁液辅助治疗,治疗组在对照组治疗基础上加用环磷腺苷葡胺注射液治疗。观察并比较两组疗效。结果：治疗组总有效率为90.6%,对照组总有效率为69.7%。两组总有效率比较,差异有统计学意义（χ2=4.45,P〈0.05）。治疗组治疗后心功能Ⅰ级22例,心功能Ⅱ级5例,共占84.4%,两组治疗后心功能分级分布比较,差异有统计学意义（Z=2.01,P〈0.05）。两组治疗期间均未见严重不良反应。结论：极化镁液与环磷酸腺苷葡胺联合治疗顽固性心衰临床治疗效果确切,患者心功能改善明显,值得进一步临床实践。     

Myosin cross-bridges do not form precise rigor bonds in hypertrophic heart muscle carrying troponin T mutations

Distribution of orientations of myosin was examined in ex-vivo myofibrils from hearts of transgenic (Tg) mice expressing Familial Hypertrophic Cardiomyopathy (FHC) troponin T (TnT) mutations I79N, F110I and R278C. Humans are heterozygous for sarcomeric FHC mutations and so hypertrophic myocardium contains a mixture of the wild-type (WT) and mutated (MUT) TnT. If mutations are expressed at a low level there may not be a significant change in the global properties of heart muscle. In contrast, measurements from a few molecules avoid averaging inherent in the global measurements. It is thus important to examine the properties of only a few molecules of muscle. To this end, the lever arm of one out of every 60,000 myosin molecules was labeled with a fluorescent dye and a small volume within the A-band (~ 1 fL) was observed by confocal microscopy. This volume contained on average 5 fluorescent myosin molecules. The lever arm assumes different orientations reflecting different stages of acto-myosin enzymatic cycle. We measured the distribution of these orientations by recording polarization of fluorescent light emitted by myosin-bound fluorophore during rigor and contraction. The distribution of orientations of rigor WT and MUT myofibrils was significantly different. There was a large difference in the width and of skewness and kurtosis of rigor distributions. These findings suggest that the hypertrophic phenotype associated with the TnT mutations can be characterized by a significant increase in disorder of rigor cross-bridges.