Sumoylation is a posttranslational modification implicated in a variety of cellular activities, and its role in a number of human pathogeneses such as cleft lip/palate has been well documented. However, the importance of the SUMO conjugation pathway in cardiac development and functional disorders is newly emerging. We previously reported that knockout of SUMO-1 in mice led to congenital heart diseases (CHDs). To further investigate the effects of imbalanced SUMO conjugation on heart development and function and its underlying mechanisms, we generated transgenic (Tg) mice with cardiac-specific expression of SENP2, a SUMO-specific protease that deconjugates sumoylated proteins, to evaluate the impact of desumoylation on heart development and function. Overexpression of SENP2 resulted in premature death of mice with CHDs—atrial septal defects (ASDs) and/or ventricular septal defects (VSDs). Immunobiochemistry revealed diminished cardiomyocyte proliferation in SENP2-Tg mouse hearts compared with that in wild type (WT) hearts. Surviving SENP2-Tg mice showed growth retardation, and developed cardiomyopathy with impaired cardiac function with aging. Cardiac-specific overexpression of the SUMO-1 transgene reduced the incidence of cardiac structural phenotypes in the sumoylation defective mice. Moreover, cardiac overexpression of SENP2 in the mice with Nkx2.5 haploinsufficiency promoted embryonic lethality and severity of CHDs, indicating the functional interaction between SENP2 and Nkx2.5 in vivo. Our findings indicate the indispensability of a balanced SUMO pathway for proper cardiac development and function.
SUMO; SENP2; congenital heart defects; cardiomyopathy; Nkx2.5
Objective: To investigate the periodontal status and associated risk factors among women of childbearing age to increase the awareness of oral health. Methods: The study was conducted on childbearing age women in Cixi, a city in Zhejiang Province in the southeast of China. A total of 754 women participated in periodontal examination while receiving prenatal care. Data of the women were collected from the Cixi Family Planning Commission and during an interview. Clinical periodontal indices, such as bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) were measured during the examination. Statistical analysis on subject-based data was performed. Results: The prevalence of periodontal disease among childbearing age women in Cixi was high (84.7%). A significant association was found between the disease and educational level, pregnancy, taking oral contraceptives, stress, alcohol consumption, overweight, dental visit, and teeth brushing (P<0.05). Women who suffered periodontal disease showed deep PD, obvious BOP, and clinical attachment loss. Among this population, pregnancy was closely associated with higher BOP percentage; teeth brushing no more than once per day or brushing for less than 1 min (P<0.001) after adjusting for age and stress. Conclusions: The periodontal status of childbearing age women in Cixi needs to be improved urgently. Attention towards the periodontal health should be warranted, especially for those in special statuses and with poor awareness.
Periodontal status; Childbearing age women; Risk factors; Pregnancy
The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses.
The fungal family, Clavicipitaceae, includes “ergot” fungi that parasitize ears of cereals and have historically caused mass poisonings, as well as “epichloae,” which are symbionts of grasses. Many epichloae are mutualistic symbionts, but some are pathogenic, and others have both mutualistic and pathogenic characteristics. Most Clavicipitaceae produce “alkaloids,” small molecules that deter insects, livestock, and wildlife from feeding on the fungus or plant. Epichloae protect their hosts with diverse alkaloids belonging to four chemical classes. After sequencing the entire DNA contents (“genomes”) of ten epichloae, three ergot fungi, and two relatives, we compared their “clusters” of genes for alkaloid biosynthesis. In the epichloae, these clusters contained extraordinarily large blocks of highly repetitive DNA, which promote gene losses, mutations, and even the evolution of new genes. These repeat blocks account for the exceptionally high alkaloid diversity in the epichloae and may relate to the ecological diversity of these symbiotic fungi.
The development of resistance to chemotherapies represents a significant barrier to successful cancer treatment. Resistance mechanisms are complex, can involve diverse and often unexpected cellular processes, and can vary with both the underlying genetic lesion and the origin or type of tumor. For these reasons developing experimental strategies that could be used to understand, identify and predict mechanisms of resistance in different malignant cells would be a major advance.
Here we describe a gain-of-function forward genetic approach for identifying mechanisms of resistance. This approach uses a modified piggyBac transposon to generate libraries of mutagenized cells, each containing transposon insertions that randomly activate nearby gene expression. Genes of interest are identified using next-gen high-throughput sequencing and barcode multiplexing is used to reduce experimental cost.
Using this approach we successfully identify genes involved in paclitaxel resistance in a variety of cancer cell lines, including the multidrug transporter ABCB1, a previously identified major paclitaxel resistance gene. Analysis of co-occurring transposons integration sites in single cell clone allows for the identification of genes that might act cooperatively to produce drug resistance a level of information not accessible using RNAi or ORF expression screening approaches.
We have developed a powerful pipeline to systematically discover drug resistance in mammalian cells in vitro. This cost-effective approach can be readily applied to different cell lines, to identify canonical or context specific resistance mechanisms. Its ability to probe complex genetic context and non-coding genomic elements as well as cooperative resistance events makes it a good complement to RNAi or ORF expression based screens.
Transposon mutagenesis; Chemotherapy; Resistance; Gene activation
Exercise training is of benefit for patients with restrictive lung disease. However, it tends to be intolerable for those with severe disease. We examined whether providing ventilatory assistance by using negative pressure ventilators (NPV) during exercise training is feasible for such patients and the effects of training.
36 patients with restrictive lung disease were prospectively enrolled for a 12-week multidisciplinary rehabilitation program. During this program, half of them (n:18; 60.3 ± 11.6 years; 6 men; FVC: 32.5 ± 11.7% predicted ) received regular sessions of exercise training under NPV, whilst the 18 others (59.6 ± 12.3 years; 8 men; FVC: 37.7 ± 10.2% predicted) did not. Exercise capacity, pulmonary function, dyspnea and quality of life were measured. The primary endpoint was the between-group difference in change of 6 minute-walk distance (6MWD) after 12 weeks of rehabilitation.
All patients in the NPV-exercise group were able to tolerate and completed the program. The between-group differences were significantly better in the NPV-exercise group in changes of 6MWD (34.1 ± 12.7 m vs. -32.5 ± 17.5 m; P = 0.011) and St George Score (−14.5 ± 3.6 vs. 11.8 ± 6.0; P < 0.01). There was an improvement in dyspnea sensation (Borg’s scale, from 1.4 ± 1.5 point to 0.8 ± 1.3 point, P = 0.049) and a small increase in FVC (from 0.85 ± 0.09 L to 0.91 ± 0.08 L, P = 0.029) in the NPV-exercise group compared to the control group.
Exercise training with NPV support is feasible for patients with severe restrictive lung diseases, and improves exercise capacity and health-related quality of life.
Restrictive lung disease; Negative pressure ventilation; Exercise training; Exercise capacity; Health-related quality of life
Previous studies have shown that the electroneutral Na+/HCO3− cotransporter NBCn2 (SLC4A10) is predominantly expressed in the central nervous system (CNS). The physiological and pathological significances of NBCn2 have been well recognized. However, little is known about the tissue specificity of expression of different NBCn2 variants. Moreover, little is known about the expression of NBCn2 proteins in systems other than CNS. Here, we identified a set of novel Slc4a10 variants differing from the originally described ones by containing a distinct 5′ untranslated region encoding a new extreme amino-terminus (Nt). Electrophysiology measurements showed that both NBCn2 variants with alternative Nt contain typical electroneutral Na+-coupled HCO3− transport activity in Xenopus oocytes. Luciferase reporter assay showed that Slc4a10 contains two alternative promoters responsible for expression of the two types of NBCn2 with distinct extreme Nt. Western blotting showed that NBCn2 proteins with the original Nt are primarily expressed in CNS, whereas those with the novel Nt are predominantly expressed in the kidney and to a lesser extent in the small intestine. Due to alternative splicing, the known NBCn2 variants contain two types of carboxyl-termini (CT) differing in the optional inclusion of a PDZ-binding motif. cDNA cloning showed that virtually all NBCn2 variants expressed in epithelial tissues contain, but the vast majority of those from the neural tissues lack the PDZ-binding motif. We conclude that alternative transcription and splicing of Slc4a10 products are regulated in a tissue-specific manner. Our findings provide critical insights that will greatly influence the study of the physiology of NBCn2.
Molecular logic gates, which have attracted increasing research interest and are crucial for the development of molecular-scale computers, simplify the results of measurements and detections, leaving the diagnosis of disease either “yes” or “no”. Prion diseases are a group of fatal neurodegenerative disorders that happen in human and animals. The main problem with a diagnosis of prion diseases is how to sensitively and selectively discriminate and detection of the minute amount of PrPRes in biological samples. Our previous work had demonstrated that dual-aptamer strategy could achieve highly sensitive and selective discrimination and detection of prion protein (cellular prion protein, PrPC, and the diseases associated isoform, PrPRes) in serum and brain. Inspired by the advantages of molecular logic gate, we further conceived a new concept for dual-aptamer logic gate that responds to two chemical input signals (PrPC or PrPRes and Gdn-HCl) and generates a change in fluorescence intensity as the output signal. It was found that PrPRes performs the “OR” logic operation while PrPC performs “XOR” logic operation when they get through the gate consisted of aptamer modified reusable magnetic microparticles (MMPs-Apt1) and quantum dots (QDs-Apt2). The dual-aptamer logic gate simplifies the discrimination results of PrPRes, leaving the detection of PrPRes either “yes” or “no”. The development of OR logic gate based on dual-aptamer strategy and two chemical input signals (PrPRes and Gdn-HCl) is an important step toward the design of prion diseases diagnosis and therapy systems.
A cohort, double blind, and randomized study was conducted to investigate the effect of a single nucleotide polymorphism of the μ-opioid receptor at nucleotide position 118 (OPRM1:c.118A>G) on the association with the most common side effects (nausea or vomiting) induced by intravenous patient control analgesia (IVPCA) with morphine, including incidence and severity analysis. A total of 129 Taiwanese women undergoing gynecology surgery received IVPCA with pure morphine for postoperative pain relief. Blood samples were collected and sequenced with high resolution melting analysis to detect three different genotypes of OPRM1 (AA, AG, and GG). All candidates 24 h postoperatively will be interviewed to record the clinical phenotype with subjective complaints and objective observations. The genotyping after laboratory analysis showed that 56 women (43.4%) were AA, 57 (44.2%) were AG, and 16 (12.4%) were GG. The distribution of genotype did not violate Hardy-Weinberg equilibrium test. There was no significant difference neither between the severity and incidence of IVPCA morphine-induced side effects and genotype nor between the association between morphine consumption versus genotype. However, there was significant difference of the relation between morphine consumption and the severity and incidence of IVPCA morphine-induced nausea and vomiting. The genetic analysis for the severity and incidence of IVPCA morphine-induced nausea or vomiting showed no association between phenotype and genotype. It might imply that OPRM1:c.118A>G does not protect against IVPCA morphine-induced nausea or vomiting.
Background Variation in the complement factor H gene (CFH) is associated with risk of late age-related macular degeneration (AMD). Previous studies have been case–control studies in populations of European ancestry with little differentiation in AMD subtype, and insufficient power to confirm or refute effect modification by smoking.
Methods To precisely quantify the association of the single nucleotide polymorphism (SNP rs1061170, ‘Y402H’) with risk of AMD among studies with differing study designs, participant ancestry and AMD grade and to investigate effect modification by smoking, we report two unpublished genetic association studies (n = 2759) combined with data from 24 published studies (26 studies, 26 494 individuals, including 14 174 cases of AMD) of European ancestry, 10 of which provided individual-level data used to test gene–smoking interaction; and 16 published studies from non-European ancestry.
Results In individuals of European ancestry, there was a significant association between Y402H and late-AMD with a per-allele odds ratio (OR) of 2.27 [95% confidence interval (CI) 2.10–2.45; P = 1.1 x 10−161]. There was no evidence of effect modification by smoking (P = 0.75). The frequency of Y402H varied by ancestral origin and the association with AMD in non-Europeans was less clear, limited by paucity of studies.
Conclusion The Y402H variant confers a 2-fold higher risk of late-AMD per copy in individuals of European descent. This was stable to stratification by study design and AMD classification and not modified by smoking. The lack of association in non-Europeans requires further verification. These findings are of direct relevance for disease prediction. New research is needed to ascertain if differences in circulating levels, expression or activity of factor H protein explain the genetic association.
Age-related macular degeneration (AMD); Complement factor H gene; meta-ananlysis
Gastrointestinal stromal tumor (GIST) is a prototype of mutant KIT oncogene-driven tumor. Prolonged tyrosine kinase inhibitor (TKI) treatment may result in a resistant phenotype through acquired secondary KIT mutation. Heat shock protein 90 (HSP90AA1) is a chaperone protein responsible for protein maturation and stability, and KIT is a known client protein of HSP90AA1. Inhibition of HSP90AA1 has been shown to destabilize KIT protein by enhancing its degradation via the proteasome-dependent pathway. In this study, we demonstrated that NVP-AUY922 (AUY922), a new class of HSP90AA1 inhibitor, is effective in inhibiting the growth of GIST cells expressing mutant KIT protein, the imatinib-sensitive GIST882 and imatinib-resistant GIST48 cells. The growth inhibition was accompanied with a sustained reduction of both total and phosphorylated KIT proteins and the induction of apoptosis in both cell lines. Surprisingly, AUY922-induced KIT reduction could be partially reversed by pharmacological inhibition of either autophagy or proteasome degradation pathway. The blockade of autophagy alone led to the accumulation of the KIT protein, highlighting the role of autophagy in endogenous KIT turnover. The involvement of autophagy in endogenous and AUY922-induced KIT protein turnover was further confirmed by the colocalization of KIT with MAP1LC3B-, acridine orange- or SQSTM1-labeled autophagosome, and by the accumulation of KIT in GIST cells by silencing either BECN1 or ATG5 to disrupt autophagosome activity. Therefore, the results not only highlight the potential application of AUY922 for the treatment of KIT-expressing GISTs, but also provide the first evidence for the involvement of autophagy in endogenous and HSP90AA1 inhibitor-induced KIT degradation.
gastrointestinal stromal tumor; KIT; heat shock protein 90 inhibitor; autophagy; imatinib resistance
Cell sheet-mediated tissue regeneration is a promising approach for corneal reconstruction. However, the fragility of bioengineered corneal endothelial cell (CEC) monolayers allows us to take advantage of cross-linked porous gelatin hydrogels as cell sheet carriers for intraocular delivery. The aim of this study was to further investigate the effects of biopolymer concentrations (5–15 wt%) on the characteristic and safety of hydrogel discs fabricated by a simple stirring process combined with freeze-drying method. Results of scanning electron microscopy, porosity measurements, and ninhydrin assays showed that, with increasing solid content, the pore size, porosity, and cross-linking index of carbodiimide treated samples significantly decreased from 508±30 to 292±42 µm, 59.8±1.1 to 33.2±1.9%, and 56.2±1.6 to 34.3±1.8%, respectively. The variation in biopolymer concentrations and degrees of cross-linking greatly affects the Young’s modulus and swelling ratio of the gelatin carriers. Differential scanning calorimetry measurements and glucose permeation studies indicated that for the samples with a highest solid content, the highest pore wall thickness and the lowest fraction of mobile water may inhibit solute transport. When the biopolymer concentration is in the range of 5–10 wt%, the hydrogels have high freezable water content (0.89–0.93) and concentration of permeated glucose (591.3–615.5 µg/ml). These features are beneficial to the in vitro cultivation of CECs without limiting proliferation and changing expression of ion channel and pump genes such as ATP1A1, VDAC2, and AQP1. In vivo studies by analyzing the rabbit CEC morphology and count also demonstrate that the implanted gelatin discs with the highest solid content may cause unfavorable tissue-material interactions. It is concluded that the characteristics of cross-linked porous gelatin hydrogel carriers and their triggered biological responses are in relation to biopolymer concentration effects.
The lack of reliable methods to efficiently isolate and propagate stem cell populations is a significant obstacle to the advancement of cell-based therapies for human diseases. One isolation technique is based on efflux of the fluorophore Hoechst 33342. Using fluorescence-activated cell sorting (FACS), a sub-population containing adult stem cells has been identified in a multitude of tissues in every mammalian species examined. These rare cells are referred to as the ‘side population’ or SP due to a distinctive FACS profile that results from weak staining by Hoechst dye. Although the SP contains multi-potent cells capable of differentiating toward hematopoietic and mesenchymal lineages; there is currently no method to efficiently expand them. Here, we describe a spinner-flask culture system containing C2C12 myoblasts attached to spherical microcarriers that act to support the growth of non-adherent, post-natal murine skeletal muscle and bone marrow SP cells. Using FACS and hemocytometry, we show expansion of unfractionated EGFP+ SP cells over 6 wks. A significant number of these cells retain characteristics of freshly-isolated, unfractionated SP cells with respect to protein expression and dye efflux capacity. Expansion of the SP will permit further study of these heterogeneous cells and determine their therapeutic potential for regenerative and reparative therapies.
Previous studies on the association between migraine and the risk of developing hemorrhagic stroke (HS) have generated inconsistent results. The aim of the present population-based, age- and sex- matched follow-up study was to investigate whether migraine is associated with an increased risk of HS.
A total of 20925 persons with at least two ambulatory visits in 2001 with the principal diagnosis of migraine were enrolled in the migraine group. The non-migraine group consisted of 104625, age- and sex- matched, randomly sampled subjects without migraine. The two-year HS-free survival rates for these 2 groups were estimated using the Kaplan-Meier method. Cox proportional hazards regression was used to estimate the effect of migraine on the occurrence of HS.
During the 2 year follow-up, 113 subjects in the migraine group (0.54%) and 255 in the non-migraine group (0.24%) developed HS. The crude hazard ratio (HR) for developing HS in the migraine group was 2.22 compared to the non-migraine group (95% confidence interval [CI]: 1.78–2.77, p<0.0001) and the adjusted HR was 2.13 (95% CI: 1.71–2.67, p<0.0001) after controlling for demographic characteristics and comorbid medical disorders.
This population-based age- and sex- matched cohort study shows that migraine was linked to an increased risk of HS.
The 9p21.3 locus is strongly associated with the risk of coronary artery disease (CAD) and with type 2 diabetes (T2D). We investigated the association of 9p21.3 variants with severity of CAD (defined by the number of vessel diseased [VD]) in the presence and absence of T2D.
We tested 11 9p21.3-variants for association in a white Italian study (N = 2,908), and carried out replication in 2 independent white populations, a German study (N = 2,028) and a Canadian Study (N=950). SNP association and permutation analyses were conducted.
We identified two 9p21.3-variants, rs4977574 (P < 4×10-4) and rs2383207 (P < 1.5×10-3) that were associated with severity of CAD in subjects without T2D. Association of rs4977574 with severity of CAD was confirmed in the Canadian Study. Results from subgroup analysis among patients with T2D showed an interaction between rs10738610 and T2D with P = 4.82×10-2. Further investigation showed that rs10738610 (P < 1.99×10-2) was found to be significantly associated with severity of CAD in subjects with T2D.
The 9p21.3 locus is significantly associated with severity of CAD. The number of associations of 9p21.3 variants with severity of CAD is variable to the presence and absence of T2D. In a CAD-susceptible region of 115 kb, there is only one variant associated with the severity of coronary vessel disease in the presence of type 2 diabetes.
Severity of CAD; Coronary artery disease; Diabetes mellitus; T2D; 9p21.3; Genetics; Single nucleotide polymorphism
The FMN–heme intraprotein electron transfer (IET) kinetics in full length and oxygenase/FMN (oxyFMN) construct of human iNOS were determined by laser flash photolysis over the temperature range from 283 to 304 K. An appreciable increase in the rate constant value was observed with an increase in the temperature. Our previous viscosity study indicated that the IET process is conformationally gated, and Eyring equation was thus used to analyze the temperature dependence data. The obtained magnitude of activation entropy for the IET in the oxyFMN construct is only one-fifth of that for the holoenzyme. This indicates that the FMN domain in the holoenzyme needs to sample more conformations before the IET takes place, and that the FMN domain in the oxyFMN construct is better poised for efficient IET.
Heme–FMN electron transfer; Nitric oxide synthase; Intraprotein kinetics; Laser flash photolysis; Temperature dependence
It is well known that the selectivity of an ion-selective electrode (ISE) depends on the stoichiometry of the complexes between its ionophore and the target and interfering ions. It is all the more surprising that the possibility for the simultaneous occurrence of multiple target ion complexes with different complex stoichiometries was mostly ignored in the past. Here we report on the simultaneous formation of 1:1 and 1:2 complexes of a fluorophilic crown ether in fluorous ISE membranes, and how this results in what look like super-Nernstian responses. These increased response slopes are not caused by mass transfer limitations and can be readily explained with a phase boundary model, a finding that is supported by experimentally determined complex formation constants and excellent fits of response curves. Not only Cs+ but also the smaller ions Li+, Na+, K+, and NH4+ form 1:1 and 1:2 complexes with the fluorophilic crown ether, with cumulative formation constants of up to 1015.0 and 1021.0 for of the 1:1 and 1:2 complexes, respectively. Super-Nernstian responses of the type observed with these electrodes are probably not particularly rare, but lacking in the past an adequate discussion in the literature remained ignored or misinterpreted. Preliminary calculations also predict sub-Nernstian responses and potential dips of a similar origin. The proper understanding of such phenomena will facilitate the development of new ISEs based on ionophores that form complexes of higher stoichiometries.
Human amniotic fluid contains cells that potentially have important stem cell characteristics, yet the programs controlling their developmental potency are unclear. Here, we provide evidence that amniocytes derived from multiple patients are marked by heterogeneity and variability in expression levels of pluripotency markers. Clonal analysis from multiple patients indicates that amniocytes have large pools of self-renewing cells that have an inherent property to give rise to a distinct amniocyte phenotype with a heterogeneity of pluripotent markers. Significant to their therapeutic potential, genome-wide profiles are distinct at different gestational ages and times in culture, but do not differ between genders. Based on hierarchical clustering and differential expression analyses of the entire transcriptome, amniocytes express canonical regulators associated with pluripotency and stem cell repression. Their profiles are distinct from human embryonic stem cells (ESCs), induced-pluripotent stem cells (iPSCs), and newborn foreskin fibroblasts. Amniocytes have a complex molecular signature, coexpressing trophoblastic, ectodermal, mesodermal, and endodermal cell-type-specific regulators. In contrast to the current view of the ground state of stem cells, ESCs and iPSCs also express high levels of a wide range of cell-type-specific regulators. The coexpression of multilineage differentiation markers combined with the strong expression of a subset of ES cell repressors in amniocytes suggests that these cells have a distinct phenotype that is unlike any other known cell-type or lineage.
Colorectal endoscopy, an effective screening intervention for colorectal cancer, is recommended for people age fifty or older, or earlier for those at higher risk. Rates of colorectal endoscopy are still far below those recommended by the US Preventive Services Task Force. This study examined whether factors such as the supply of gastroenterologists and the proportion of the local population without health insurance coverage were related to the likelihood of having the procedure, and whether these factors explained racial and ethnic differences in colorectal endoscopy. We found evidence that improving access to health care at the county and individual levels through expanded health insurance coverage could improve colorectal endoscopy use but might not be sufficient to reduce racial and ethnic disparities in colorectal cancer screening. Policy action to address these disparities will need to consider other structural and cultural factors that may be inhibiting colorectal cancer screening.
Outcrossing is known to carry genetic advantages in comparison with inbreeding. In many cases, flowering plants develop a self-incompatibility mechanism, along with a floral component adaptation mechanism, to avoid self-pollination and to promote outbreeding. Orchids commonly have a lip in their flower that functions as the a visiting plate for insect pollinators. Aside from the lip, however, many species (including Coelogyne rigida) have sheaths around the axis of inflorescence. The function of these sheaths remains unknown, and has long been a puzzle to researchers.
We investigated the function of these sheaths in relation to the lip and the pollinators, as well as their role in the modes of pollination and reproduction of Coelogyne rigida in 30 flowering populations of orchids in the limestone area of Southeast Yunnan, China. We found that self-incompatible C. rigida developed specialized bird perches around the basal axis of inflorescence to attract sunbirds and to complement their behavioral tendency to change foraging locations frequently. This self-incompatibility mechanism operates separately from the floral component adaptation mechanism. This mechanism thus prevents bees from repeatedly visiting the floral lip of the same plant which, in turn, results in autogamy. In this way, instead of preventing autogamy, C. rigida responds to these negative effects through a highly efficient cross-pollination method that successfully transfers pollen to different plants.
The proposed method ensures reproductive success, while offsetting the infertile self-pollination by insects, thereby reducing mating costs and addressing the lack of cross-pollination. The adaptation provides a novel and striking example of structural adaptation that promotes cross-pollination in angiosperms.
Parkinson's disease (PD) is a common neurodegenerative disease caused by genetic and environmental factors. We analyzed induced pluripotent stem cell (iPSC)-derived neural cells from PD patients and presymptomatic individuals carrying mutations in the PINK1 and LRRK2 genes, and healthy control subjects. We measured several aspects of mitochondrial responses in the iPSC-derived neural cells including production of reactive oxygen species, mitochondrial respiration, proton leakage and intraneuronal movement of mitochondria. Cellular vulnerability associated with mitochondrial function in iPSC-derived neural cells from PD patients and at-risk individuals could be rescued with coenzyme Q10, rapamycin or the LRRK2 kinase inhibitor GW5074. Analysis of mitochondrial responses in iPSC-derived neural cells from PD patients carrying different mutations provides insights into convergence of cellular disease mechanisms between different familial forms of PD and highlights the importance of oxidative stress and mitochondrial dysfunction in PD.
Zoledronic acid, an inhibitor of osteoclast-mediated bone resorption, has been shown to have both direct and indirect antitumor activity. However, its use in extraskeletal malignancy is limited due to rapid uptake and accumulation within bone. Polyinosinic acid-polycytidylic acid [poly (I:C)] is a synthetic double-stranded RNA with direct antitumor cytotoxicity if it can be delivered to tumor cells intracellularly.
Cationic lipid-coated calcium phosphate nanoparticles (LCP) were developed to enable intracellular codelivery of zoledronic acid and poly (I:C). LCP codelivering zoledronic acid and poly (I:C) were prepared using an ethanol injection method. Briefly, the ethanol solution of lipids was rapidly injected into newly formed calcium phosphate crystals containing poly (I:C) and zoledronic acid, and the mixture was then sonicated briefly to form LCP. The LCP were fully characterized for mean diameter size and zeta potential, efficiency in loading zoledronic acid, cytotoxic effect in a B16BL6 melanoma cell line in vitro, and antitumor effect in B16BL6 melanoma-bearing mice.
LCP with a mean diameter around 200 nm and a narrow size distribution (polydispersity index 0.17) and high zoledronic acid encapsulation efficiency (94%) were achieved. LCP loaded with zoledronic acid and poly (I:C) had significantly greater antitumor activity than the free drugs in the B16BL6 melanoma cell line (P < 0.05). Furthermore, codelivery of zoledronic acid and poly (I:C) by LCP had higher cytotoxicity than delivering poly (I:C) alone by LCP (P < 0.05), indicating a synergism between zoledronic acid and poly (I:C). Finally, the antitumor study in melanoma-bearing mice also demonstrated synergism between zoledronic acid and poly (I:C) codelivered by LCP.
Cationic lipid-coated calcium phosphate nanoparticles constructed for codelivery of zoledronic acid and double-stranded RNA poly (I:C) had better antitumor activity both in vitro and in vivo. Future preclinical development of LCP encapsulating zoledronic acid and poly (I:C) for the treatment of human cancer is under way.
calcium phosphate; lipid-coated nanoparticles; zoledronic acid; double-stranded RNA; poly (I:C); codelivery
Functional magnetic resonance imaging (fMRI), at high magnetic field strength can suffer from serious degradation of image quality because of motion and physiological noise, as well as spatial distortions and signal losses due to susceptibility effects. Overcoming such limitations is essential for sensitive detection and reliable interpretation of fMRI data. These issues are particularly problematic in studies of awake animals. As part of our initial efforts to study functional brain activations in awake, behaving monkeys using fMRI at 4.7T, we have developed acquisition and analysis procedures to improve image quality with encouraging results.
We evaluated the influence of two main variables on image quality. First, we show how important the level of behavioral training is for obtaining good data stability and high temporal signal-to-noise ratios. In initial sessions, our typical scan session lasted 1.5 hours, partitioned into short (<10 minutes) runs. During reward periods and breaks between runs, the monkey exhibited movements resulting in considerable image misregistrations. After a few months of extensive behavioral training, we were able to increase the length of individual runs and the total length of each session. The monkey learned to wait until the end of a block for fluid reward, resulting in longer periods of continuous acquisition. Each additional 60 training sessions extended the duration of each session by 60 minutes, culminating, after about 140 training sessions, in sessions that last about four hours. As a result, the average translational movement decreased from over 500 μm to less than 80 μm, a displacement close to that observed in anesthetized monkeys scanned in a 7 T horizontal scanner.
Another major source of distortion at high fields arises from susceptibility variations. To reduce such artifacts, we used segmented gradient-echo echo-planar imaging (EPI) sequences. Increasing the number of segments significantly decreased susceptibility artifacts and image distortion. Comparisons of images from functional runs using four segments with those using a single-shot EPI sequence revealed a roughly two-fold improvement in functional signal-to-noise-ratio and 50% decrease in distortion. These methods enabled reliable detection of neural activation and permitted blood-oxygenation-level-dependent (BOLD) based mapping of early visual areas in monkeys using a volume coil.
In summary, both extensive behavioral training of monkeys and application of segmented gradient-echo EPI sequence improved signal-to-noise and image quality. Understanding the effects these factors have is important for the application of high field imaging methods to the detection of sub-millimeter functional structures in the awake monkey brain.
Functional MRI; Non-human primate; Macaque monkey; Awake; Visual cortex; Data stability
Emerging evidence supports an important role of posterior parasylvian areas in both pain and touch processing. Whether there are separate or shared networks for these sensations remains controversial. The present study compared spatial patterns of brain activation in response to unilateral nociceptive heat (47.5° C) or innocuous tactile stimulation (8 Hz vibration) to digits through high-resolution fMRI in squirrel monkeys. In addition, the temporal profile of heat stimulus evoked fMRI BOLD signal changes was characterized. By examining high-resolution fMRI and histological measures at both the individual and group levels, we found that both nociceptive heat and tactile stimuli elicited activation in bilateral secondary somatosensory and ventral parietal areas (S2/PV) and in ipsilateral ventral somatosensory area (VS) and retroinsula (Ri). Bilateral posterior insular cortex (pIns) and area 7b responded preferentially to nociceptive heat stimulation. Single voxels within each activation cluster showed robust BOLD signal changes during each block of nociceptive stimulation. Across animals (n = 11), nociceptive response magnitudes of contralateral VS and pIns, and ipsilateral Ri were significantly greater than corresponding areas in the opposite hemisphere. In sum, both distinct and shared areas in regions surrounding the posterior sylvian fissure were activated in response to nociceptive and tactile inputs in non-human primates.
nociception; hand; primates; cortex; touch; fMRI
Semiparametric transformation models provide a very general framework for studying the effects of (possibly time-dependent) covariates on survival time and recurrent event times. Assessing the adequacy of these models is an important task because model misspecification affects the validity of inference and the accuracy of prediction. In this paper, we introduce appropriate time-dependent residuals for these models and consider the cumulative sums of the residuals. Under the assumed model, the cumulative sum processes converge weakly to zero-mean Gaussian processes whose distributions can be approximated through Monte Carlo simulation. These results enable one to assess, both graphically and numerically, how unusual the observed residual patterns are in reference to their null distributions. The residual patterns can also be used to determine the nature of model misspecification. Extensive simulation studies demonstrate that the proposed methods perform well in practical situations. Three medical studies are provided for illustrations.
Goodness of fit; Martingale residuals; Model checking; Model misspecification; Model selection; Recurrent events; Survival data; Time-dependent covariate
Manganese(III) complexes of three fluorophilic salen derivatives were used to prepare ion-selective electrodes (ISEs) with ionophore-doped fluorous sensing membranes. Because of their extremely low polarity and polarizability, fluorous media are not only chemically very inert but also solvate potentially interfering ions poorly, resulting in a much improved discrimination of such ions. Indeed, the new ISEs exhibited selectivities for CO32− that exceed those of previously reported ISEs based on non-fluorous membranes by several orders of magnitude. In particular, the interference from chloride and salicylate was reduced by two and six orders of magnitude, respectively. To achieve this, the selectivities of these ISEs were fine-tuned by addition of non-coordinating hydrophobic ions (i.e., ionic sites) into the sensing membranes. Stability constants of the anion–ionophore complexes were determined from the dependence of the potentiometric selectivities on the charge sign of the ionic sites and the molar ratio of ionic sites and the ionophore. For this purpose, a previously introduced fluorophilic tetraphenylborate and a novel fluorophilic cation with a bis(triphenylphosphoranylidene)ammonium group, (Rf6(CH2)3)3PN+P(Rf6(CH2)3)3, were utilized. The optimum CO32− selectivities were found for sensing membranes composed of anionic sites and ionophore in a 1:4 molar ratio, which results in the formation of 2:1 complexes with CO32− with stability constants up to 4.1 × 1015. As predicted by established theory, the site-to-ionophore ratios that provide optimum potentiometric selectivity depend on the stoichiometries of the complexes of both the primary and the interfering ions. However, the ionophores used in this study give examples of charges and stoichiometries previously neither explicitly predicted by theory nor shown by experiment. The exceptional selectivity of fluorous membranes doped with these carbonate ionophores suggests their use not only for potentiometric sensing but also for other types of sensors, such as the selective separation of carbonate from other anions and the sequestration of carbon dioxide.