Retinal Arteriolar Morphometry Based on Full Width at Half Maximum Analysis of Spectral-Domain Optical Coherence Tomography Images

Objectives

In this study, we develop a microdensitometry method using full width at half maximum (FWHM) analysis of the retinal vascular structure in a spectral-domain optical coherence tomography (SD-OCT) image and present the application of this method in the morphometry of arteriolar changes during hypertension.

Methods

Two raters using manual and FWHM methods measured retinal vessel outer and lumen diameters in SD-OCT images. Inter-rater reproducibility was measured using coefficients of variation (CV), intraclass correlation coefficient and a Bland-Altman plot. OCT images from forty-three eyes of 43 hypertensive patients and 40 eyes of 40 controls were analyzed using an FWHM approach; wall thickness, wall cross-sectional area (WCSA) and wall to lumen ratio (WLR) were subsequently calculated.

Results

Mean difference in inter-rater agreement ranged from -2.713 to 2.658 μm when using a manual method, and ranged from -0.008 to 0.131 μm when using a FWHM approach. The inter-rater CVs were significantly less for the FWHM approach versus the manual method (P < 0.05). Compared with controls, the wall thickness, WCSA and WLR of retinal arterioles were increased in the hypertensive patients, particular in diabetic hypertensive patients.

Conclusions

The microdensitometry method using a FWHM algorithm markedly improved inter-rater reproducibility of arteriolar morphometric analysis, and SD-OCT may represent a promising noninvasive method for in vivo arteriolar morphometry.     

Effects of size,neighbors, and site condition on tree growth in a subtropical evergreen and deciduous broad‐leaved mixed forest,China

Successful growth of a tree is the result of combined effects of biotic and abiotic factors. It is important to understand how biotic and abiotic factors affect changes in forest structure and dynamics under environmental fluctuations. In this study, we explored the effects of initial size [diameter at breast height (DBH)], neighborhood competition, and site condition on tree growth, based on a 3‐year monitoring of tree growth rate in a permanent plot (120 × 80 m) of montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest on Mt. Shennongjia, China. We measured DBH increments every 6 months from October 2011 to October 2014 by field‐made dendrometers and calculated the mean annual growth rate over the 3 years for each individual tree. We also measured and calculated twelve soil properties and five topographic variables for 384 grids of 5 × 5 m. We defined two distance‐dependent neighborhood competition indices with and without considerations of phylogenetic relatedness between trees and tested for significant differences in growth rates among functional groups. On average, trees in this mixed montane forest grew 0.07 cm year^?1 in DBH. Deciduous, canopy, and early‐successional species grew faster than evergreen, small‐statured, and late‐successional species, respectively. Growth rates increased with initial DBH, but were not significantly related to neighborhood competition and site condition for overall trees. Phylogenetic relatedness between trees did not influence the neighborhood competition. Different factors were found to influence tree growth rates of different functional groups: Initial DBH was the dominant factor for all tree groups; neighborhood competition within 5 m radius decreased growth rates of evergreen trees; and site condition tended to be more related to growth rates of fast‐growing trees (deciduous, canopy, pioneer, and early‐successional species) than the slow‐growing trees (evergreen, understory, and late‐successional species).     

高光谱技术——生态学领域研究的新方法

高光谱技术是一种新的地物探测技术,该技术以其敏锐的地物光谱特征探测能力为精准识别地物属性提供了强有力的手段,在生态系统过程与属性研究中具有广阔的应用前景。该文以可见光-近红外光谱分析技术为例概述了高光谱技术的原理、特点与优势,以及高光谱技术分析的流程;总结并归纳了其在土壤、植物生理、农产品品质检测、凋落物分解方面的研究应用,指出高光谱技术与遥感成像技术结合在生态监测研究中的优势;归纳了高光谱技术应用中面临的问题,并希望高光谱技术在生态学领域研究中得到更广泛的应用。     

Effect of Cytochrome b5 Content on the Activity of Polymorphic CYP1A2, 2B6, and 2E1 in Human Liver Microsomes

Human cytochrome b5 (Cyt b5) plays important roles in cytochrome P450 (CYP)-mediated drug metabolism. However, the expression level of Cyt b5 in normal human liver remains largely unknown. The effect of Cyt b5 on overall CYP activity in human liver microsomes (HLM) has rarely been reported and the relationship between Cyt b5 and the activity of polymorphic CYP has not been systematically investigated. In this study, we found that the median value of Cyt b5 protein was 270.01 pmol/mg from 123 HLM samples, and 12- and 19-fold individual variation was observed in Cyt b5 mRNA and protein levels, respectively. Gender and smoking clearly influenced Cyt b5 content. In addition, we found that Cyt b5 protein levels significantly correlated with the overall activity of CYP1A2, 2B6, and 2E1 in HLM. However, when the CYP activities were sorted by single nucleotide polymorphisms (SNP), the effect of Cyt b5 protein on the kinetic parameters varied greatly. There were significant correlations between Cyt b5 content and V_max and CL_int of CYP1A2 wild-types (3860GG, 2159GG, and 5347CC) as well as homozygous mutants (163AA and 3113GG). In contrast to V_max and CL_int, the K_m of CYP2B6 516GG and 785AA genotypes was inversely associated with Cyt b5 content. Correlations between Cyt b5 content and V_max and CL_int of CYP2E1 -1293GG, -1293GC, 7632TT, 7632TA, -333TT, and -352AA genotypes were also observed. In conclusion, Cyt b5 expression levels varied considerably in the Chinese cohort from this study. Cyt b5 had significant impact on the overall activity of CYP1A2, 2B6, and 2E1 in HLM and the effects of Cyt b5 protein on polymorphic CYP1A2, 2B6, and 2E1 activity were SNP-dependent. These findings suggest that Cyt b5 plays an important role in CYP-mediated activities in HLM and may possibly be a contributing factor for the individual variation observed in CYP enzyme activities.     

Subcutaneous Construction of Engineered Adipose Tissue with Fat Lobule-Like Structure Using Injectable Poly-Benzyl-L-Glutamate Microspheres Loaded with Adipose-Derived Stem Cells

Porous microcarriers were fabricated from synthesized poly(γ-benzyl-L-glutamate) (PBLG) polymer to engineer adipose tissue with lobule-like structure via the injectable approach. The adipogenic differentiation of human adipose-derived stem cells (hASCs) seeded on porous PBLG microcarriers was determined by adipogenic gene expression and glycerol-3-phosphate dehydrogenase enzyme activity. In vitro adipogenic cultivation was performed for 7 days, and induced hASC/PBLG complex (Adi-ASC/PBLG group) was subcutaneously injected into nude mice. Injections of PBLG microcarriers alone (PBLG group) and non-induced hASC/PBLG complex (ASC/PBLG group) served as controls. Newly formed tissues were harvested after 4 and 8 weeks. Generation of subcutaneous adipose tissue with typical lobule-like structure separated by fibrous septa was observed upon injection of adipogenic-induced hASC/microsphere complex. Adipogenesis significantly increased in the Adi-ASC/PBLG group compared with the control groups. The angiogenesis in the engineered adipose tissue was comparable to that in normal tissue as determined by capillary density and luminal diameter. Cell tracking assay demonstrated that labeled hASCs remained detectable in the neo-generated tissues 8 weeks post-injection using green fluorescence protein-labeled hASCs. These results indicate that adipose tissue with typical lobule-like structure could be engineered using injectable porous PBLG microspheres loaded with adipogenic-induced hASCs.     

Proteomic Analysis of Fetal Ovary Reveals That Ovarian Developmental Potential Is Greater in Meishan Pigs than in Yorkshire Pigs

Time-dependent expression of functional proteins in fetal ovaries is important to understand the developmental process of the ovary. This study was carried out to enhance our understanding of the developmental process of porcine fetal ovaries and to better address the differences in fetal ovary development of local and foreign pigs. The objective of the present study is to test the expression of key proteins that regulate the growth and development of fetal ovaries in Meishan and Yorkshire porcine breeds by using proteomics technology. Six Meishan and 6 Yorkshire pregnant gilts were used in this experiment. Fetal ovaries were obtained from Yorkshire and Meishan gilts on days 55 and 90 of the gestation period. Using 2D-DIGE (two dimensional-difference in gel electrophoresis) analysis, the results showed that there are about 1551 and 1400 proteins in gilt fetal ovaries on days 55 and 90, respectively of the gestation. Using MALDI TOF-TOF MS analysis, 27 differentially expressed proteins were identified in the fetal ovaries of the 2 breeds on day 55 of gestation, and a total of 18 proteins were identified on day 90 of gestation. These differentially expressed proteins were involved in the regulation of biological processes (cell death, stress response, cytoskeletal proteins) and molecular functions (enzyme regulator activity). We also found that alpha-1-antitrypsin, actin, vimentin, and PP2A proteins promote the formation of primordial follicles in the ovaries of Yorkshire pigs on day 55 of gestation while low expression heat shock proteins and high expression alpha-fetoproteins (AFP) may promote Meishan fetal ovarian follicular development on day 90 of gestation. These findings provide a deeper understanding of how reduced expression of heat shock proteins and increased expression of AFP can significantly reduce the risk of reproductive disease in obese Meishan sows. Our study also shows how these proteins can increase the ovulation rate and may be responsible for the low reproductive efficiency reported in other obese breeds. The ovarian developmental potential was found to be greater in Meishan pigs than in Yorkshire pigs.     

Intraovarian Transplantation of Female Germline Stem Cells Rescue Ovarian Function in Chemotherapy-Injured Ovaries

Early menopause and infertility often occur in female cancer patients after chemotherapy (CTx). For these patients, oocyte/embryo cryopreservation or ovarian tissue cryopreservation is the current modality for fertility preservation. However, the above methods are limited in the long-term protection of ovarian function, especially for fertility preservation (very few females with cancer have achieved pregnancy with cryopreserved ovarian tissue or eggs until now). In addition, the above methods are subject to their scope (females with no husband or prepubertal females with no mature oocytes). Thus, many females who suffer from cancers would not adopt the above methods pre- and post-CTx due to their uncertainty, safety and cost-effectiveness. Therefore, millions of women have achieved long-term survival after thorough CTx treatment and have desired to rescue their ovarian function and fertility with economic, durable and reliable methods. Recently, some studies showed that mice with infertility caused by CTx can produce normal offspring through intraovarian injection of exogenous female germline stem cells (FGSCs). Though exogenous FGSC can be derived from mice without immune rejection in the same strain, it is difficult to obtain human female germline stem cells (hFGSCs), and immune rejection could occur between different individuals. In this study, infertility in mice was caused by CTx, and the ability of FGSCs to restore ovarian function or even produce offspring was assessed. We had successfully isolated and purified the FGSCs from adult female mice two weeks after CTx. After infection with GFP-carrying virus, the FGSCs were transplanted into ovaries of mice with infertility caused by CTx. Finally, ovarian function was restored and the recipients produced offspring long-term. These findings showed that mice with CTx possessed FGSCs, restoring ovarian function and avoiding immune rejection from exogenous germline stem cells.     

Functional Characterization of Hevea brasiliensis CRT/DRE Binding Factor 1 Gene Revealed Regulation Potential in the CBF Pathway of Tropical Perennial Tree

Rubber trees (Hevea brasiliensis) are susceptible to low temperature and therefore are only planted in the tropical regions. In the past few decades, although rubber trees have been successfully planted in the northern margin of tropical area in China, they suffered from cold injury during the winter. To understand the physiological response under cold stress, we isolated a C-repeat binding factor 1 (CBF1) gene from the rubber tree. This gene (HbCBF1) was found to respond to cold stress but not drought or ABA stress. The corresponding HbCBF1 protein showed CRT/DRE binding activity in gel shift experiment. To further characterize its molecular function, the HbCBF1 gene was overexpressed in Arabidopsis. The HbCBF1 over expression (OE) line showed enhanced cold resistance and relatively slow dehydration, and the expression of Arabidopsis CBF pathway downstream target genes, e.g. AtCOR15a and AtRD29a, were significantly activated under non-acclimation condition. These data suggest HbCBF1 gene is a functional member of the CBF gene family, and may play important regulation function in rubber tree.     

MicroRNA-203 Is a Prognostic Indicator in Bladder Cancer and Enhances Chemosensitivity to Cisplatin via Apoptosis by Targeting Bcl-w and Survivin

Resistance to cisplatin-based chemotherapy is a major cause of treatment failure in advanced bladder cancer (BC) patients. There is increasing evidence that microRNAs are involved in the development and progression of BC. However, little is known about the function of microRNAs in predicting the effect of adjuvant chemotherapy on BC survival and regulating response to cisplatin. To address this issue, we employed RT-qPCR to evaluate the clinical significance of miR-203 expression in 108 tissues of BC patients receiving cisplatin-based adjuvant chemotherapy, and performed in vitro studies to explore chemotherapeutic sensitivity to cisplatin in miR-203 overexpressing BC cells. We found miR-203 levels were significantly lower in BC progression group than non-progression group (P<0.001). ROC curve analysis illustrated miR-203 could significantly distinguish progressed patients from those without progression (P<0.001), yielding an area under the ROC curve of 0.839 (95% CI, 0.756–0.903). Moreover, low miR-203 expression correlated with shortened progression free survival (PFS) and overall survival (OS) of BC patients, and was an independent prognostic factor. Overexpression of miR-203 in 5637 and T24 BC cells could decrease cell viability, enhance cisplatin cytotoxicity, and promote apoptosis. Western blotting and luciferase reporter assay showed Bcl-w and Survivin were direct downstream targets of miR-203. There was also a significant inverse association between miR-203 and Bcl-w or Survivin expression in BC tissues (r = -0.781, -0.740, both P<0.001). In conclusion, decreased miR-203 predicts progression and poor prognosis for BC patients treated with cisplatin-based chemotherapy while miR-203 overexpression can enhance cisplatin sensitization by promoting apoptosis via directly targeting Bcl-w and Survivin.