Surfactant-like Additives Assisted the Lateral Growth of Pentacene Films

Lateral growth of thin films is crucial for organic electronic devices, such as field-effect transistors. Here, we report a strategy to improve the lateral growth of pentacene films using rubrene as a surfactant-like additive. Atomic force microscopy (AFM) images confirm the enhanced lateral growth with the presence of rubrene, resulting in smooth and enlarged molecule domains in the films in comparison to those without rubrene. Molecular dynamics simulations are conducted to explore the interlayer diffusion of pentacene molecules during the growth. With the rubrene molecules as surfactant-like additives, mean square displacement (MSD) analysis shows that the pentacene molecules have a descending diffusion coefficient of 2.0 × 10-5 cm2 s-1, which is greater than the ascending diffusion coefficient of 1.6 × 10-5 cm2 s-1. The more descending molecules lead to an enhanced lateral growth of pentacene films, which is in good agreement with the experiments. As a result, the pentacene films grown with rubrene exhibit a rapid increase in carrier mobility over thickness due to the well-connected domains resulting from enhanced lateral growth. This finding will provide a new strategy to modulate the morphology of organic films for high-performance devices.

O021 Evaluating the impact of neurosurgical rotation experience in Africa on the interest and perception of medical students towards a career in neurosurgery: a continental, multi-centre, cross-sectional study

Introduction

Africa has the second-highest neurosurgical workforce deficit globally, and many medical students in Africa lack exposure to the field. This study aims to assess the impact of a neurosurgical rotation during medical school in shaping the perception and interest of students towards a career in neurosurgery.

Methods

This is a continental, multi-centre, cross-sectional study. A Google Form e-survey was disseminated to African clinical medical students between February 21st and March 20th, 2021. Data was analysed using descriptive statistics and adjusted logistic regression modelling.

Results

Data was received from 539 students in 30 African countries (n=30/54, 55.6%). The majority of participants were male (n=289/539, 53.6%) and were from Kenya (n=83/539, 15.4%). Most students had undertaken a clinical neurosurgery rotation (n=278/539, 51.6%); the majority reported a rotation length of four weeks or less (n=181/278, 65.1%). Students with clinical experience were less likely to pursue the specialty (p=0.02) and had a stronger perception that it is more difficult for women to pursue neurosurgery (p=0.0001) when compared to those without clinical experience. However, after adjusting for other factors, students with greater than four weeks of neurosurgical exposure were more likely to express a career interest in neurosurgery (odds ratio [OR]=1.75, p<0.04) and men were more likely to express interest in a neurosurgical career compared to women (OR=3.22, p<0.001).

Conclusion

Our findings support standardised, continent-wide, curriculum development, and advocacy supporting improved gender inclusivity in education and policy-making to improve the quality of neurosurgical exposure during medical school and tackle the workforce deficit across Africa.

Take-home message

A continent-wide, standardised curriculum guide to neurosurgical rotations, and advocacy for gender inclusivity in education and policy-making efforts across the African continent is required to shape the perception and interest of medical students towards a career in neurosurgery.

Systemic Immune-Inflammation Index Predicts 3-Month Functional Outcome in Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis

Background and Purpose

Systemic immune-inflammation index (SII), a novel inflammation index derived from counts of circulating platelets, neutrophils and lymphocytes, has been studied in developing incident cancer. However, the clinical value of SII in acute ischemic stroke (AIS) patients had not been further investigated. Therefore, we aimed to explore the association between SII and severity of stroke as well as 3-month outcome of AIS patients.

Methods

A total of 216 AIS patients receiving intravenous thrombolysis (IVT) and 875 healthy controls (HCs) were retrospectively recruited. Blood samples were collected within 24h after admission. Severity of stroke was assessed by the National Institute of Health stroke scale (NIHSS) scores on admission and poor 3-month functional outcome was defined as Modified Rankin Scale (mRS) > 2.

Results

SII levels in AIS patients were higher than in HCs. The cut-off value of SII is 545.14×10⁹/L. Patients with SII > 545.14×10⁹/L had higher NIHSS scores (median: 5 vs 9, p < 0.001), a positive correlation between SII and NIHSS was observed (rs = 0.305, p < 0.001). Multivariate logistic regression analyses showed that high SII was one of the independent risk factors for poor prognosis at 3 months of AIS patients (OR = 3.953, 95% CI = 1.702-9.179, p = 0.001). The addition of SII to the conventional prognostic model improved the reclassification (but not discrimination) of the functional outcome (net reclassification index 39.3%, p = 0.007).

Conclusion

SII is correlated with stroke severity at admission and can be a novel prognostic biomarker for AIS patients treated with IVT.

Patterns of CSF Inflammatory Markers in Non-demented Older People: A Cluster Analysis

Objective

In this study, we aimed to examine if patterns of CSF inflammatory markers are correlated with global cognition, episodic memory, hippocampal volume, and CSF AD-related pathologies among non-demented older people.

Methods

We included 217 non-demented older individuals, including 87 subjects with normal cognition (NC) and 130 subjects with mild cognitive impairment (MCI) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) study. Hierarchical cluster analysis including nine inflammatory markers in CSF [Tumor necrosis factor-α(TNF-α), TNF-R1, TNF-R2, transforming growth factor-β1 (TGF-β1), TGF-β2, TGF-β3, Interleukin-21 (IL-21), IL-6, and IL-7] was conducted.

Results

We identified two clusters among non-demented older people based on nine inflammatory markers in CSF. Compared to the first cluster, the second cluster showed significantly higher levels of CSF inflammatory markers (TNF-R1, TNF-R2, TGF-β1, TGF-β3, and IL-6). Further, the second cluster was also associated with higher levels of t-tau and p-tau levels in CSF.

Conclusion

We observed a subgroup of non-demented older people characterized by increased levels of inflammatory markers in CSF. Further, this subgroup showed higher levels of t-tau and p-tau levels in CSF.

microRNA-155 attenuates profibrotic effects of transforming growth factor-beta on human lung fibroblasts

Transforming growth factor-beta (TGF-β) functions in fibrogenesis as a profibrotic mediator, regulating cell proliferation, migration, apoptosis and collagen production of fibroblasts. microRNA-155 (miR-155), the expression of which has been related to bleomycin-induced idiopathic pulmonary fibrosis, has been involved in TGF-β induced epithelial-mesenchymal transition. Here, we found that miR-155 expression was decreased in human pulmonary fibroblasts by TGF-β treatment. We overexpressed miR-155 in fibroblasts to investigate the functional impact of miR-155 on TGF-β-induced fibrotic phenotype of fibroblasts. It is suggested that miR-155 overexpression attenuated the stimulatory effect of TGF-β on fibroblast proliferation, migration and collagen synthesis, by evidence from assessment of cell cycle, viability, apoptosis, migration and collagen content. Furthermore, quantitative measurement showed that SMAD1 gene expression was decreased following miR-155 inhibition, thereby demonstrating an indirect miRNA-SMAD interaction that links miR-155 to TGF-β signaling. Our work helped uncover an miRNA-mediated mechanism of fibroblast response to TGF-β. Moreover, it will help to achieve a better understanding of the regulatory roles of miR-155 in fibrogenesis.

Self-assembly of 5,6-dihydroxyindole-2-carboxylic acid: polymorphism of a eumelanin building block on Au(111)

Investigating two-dimensional (2D) self-assembled structures of biological monomers governed by intermolecular interactions is a prerequisite to understand the self-assembly of more complex biomolecular systems. 5,6-Dihydroxyindole carboxylic acid (DHICA) is one of the building blocks of eumelanin - an irregular heteropolymer and the most common form of melanin which has potential applications in organic electronics and bioelectronics. By means of scanning tunneling microscopy, density functional theory and Monte Carlo calculations, we investigate DHICA molecular configurations and interactions underlying the multiple 2D patterns formed on Au(111). While DHICA self-assembled molecular networks (SAMNs) are dominated by the hydrogen bonding of carboxylic acid dimers, a variety of 2D architectures are formed due to the multiple weak interactions of the catechol group. The hydroxyl group also allows for redox reactions, caused by oxidation via O2 exposure, resulting in molecular rearrangement. The susceptibility of the molecules to oxidation is affected by their SAMNs architectures, giving insights on the reactivity of indoles as well as highlighting non-covalent assembly as an approach to guide selective oxidation reactions.

A method for characterising human intervertebral disc glycosaminoglycan disaccharides using liquid chromatography-mass spectrometry with multiple reaction monitoring

Intervertebral disc (IVD) degeneration results in the depletion of proteoglycans and glycosaminoglycans (GAGs), which can lead to structural and mechanical loss of IVD function, ingrowth of nociceptive nerve fibres and eventually discogenic pain. Specific GAG types as well as their disaccharide patterns can be predictive of disease and degeneration in several tissues but have not been comprehensively studied within the IVD. A highly sensitive mass spectrometry based technique with multiple reaction monitoring (MRM) was used to provide characterisation of chondroitin sulphate (CS), hyaluronic acid (HA), heparan sulphate (HS) and their disaccharide sulphation patterns across different anatomical regions of human IVDs. Principal component analysis further distinguished important regional variations and proposed potential ageing variations in GAG profiles. CS was the GAG in greatest abundance in the IVD followed by HA and HS. Principal component analysis identified clear separation of GAG profiles between nucleus pulposus and annulus fibrosus in young and old specimens. Distinct patterns of predominantly expressed disaccharides of CS and HS between young and old IVD samples, provided preliminary evidence that important alterations in disaccharides occur within IVDs during ageing. This technique offered a novel approach to identify and quantify specific GAG disaccharides in human IVDs and the data presented were the first to offer insight into the spatial distribution as well as association with ageing of GAGs and GAG disaccharide sulphation patterns across the human IVD.

[The value of different antibodies detection in diagnosis of rheumatism with uveitis]

Objective: To investigate the value of HLA-B27 antigen, antinuclear antibody (ANA), anti-dsDNA and Anti-Neutrophil Cytoplasmic Antibodies (ANCA) detection in diagnosis of rheumatism with uveitis. Methods: Seven hundred and twenty four newly diagnosed patients with non-infection uveitis in Beijing Tongren Hospital from March 2012 to March 2016 who long-term lived in Beijing and its surrounding areas were continuously enrolled. HLA-B27 antigen expressions in peripheral blood lymphocytes and ANA, anti-dsDNA and ANCA levels in serum were tested. The detailed clinical data, imaging examinations and pathological examinations were recorded to define whether the patients had rheumatism and the types of rheumatism. Results: There were 285 patients were diagnosed with rheumatism in 724 patients (39.4%), with 135 male (47.4%) and 150 female (52.6%). The mean age of male (41±14) was lower than that of female (44±14), with statistically significant (t=2.18, P<0.05). There were 176 patients with Spondyloarthropathies, 48 patients with primary systemic vasculitis, 22 patients with systemic lupus erythematosus, 18 patients with primary Sjogren's syndrome, 16 patients with rheumatoid arthritis and 5 patients with juvenile idiopathic arthritis in 285 rheumatism patients. The positive rate of HLA-B27(57.2%), ANA(15.8%), anti-dsDNA (5.3%) and ANCA(9.1%) in rheumatic uveitis patients were obviously higher than those of non-rheumatic uveitis patients [HLA-B27(1.1%), ANA(1.6%), anti-dsDNA (0.0%) and ANCA(0.9%)], with statistically significant (Fisher's exact test, P<0.01). The HLA-B27 positive antigen were mainly in patients with Spondyloarthropathies, rate was 92.1%; the positive ANA were mainly in patients with systemic lupus erythematosus, rate was 95.5%; the positive anti-dsDNA were mainly in patients with systemic lupus erythematosus, rate was 59.1%; the positive ANCA were mainly in patients with primary systemic vasculitis (besides Behcet disease), rate was 57.1%. Conclusions: The detections of HLA-B27 antigen, ANA, anti-dsDNA and ANCA are valuable for primary screening of some rheumatic uveitis. There fore, clinicians should select targeted laboratory examination combine with the patients' clinical manifestations. This will be helpful in the auxiliary diagnosis of some types of rheumatic uveitis.

A meta-analysis of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer

OBJECTIVES

To evaluate the diagnostic value of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer (NSCLC).

MATERIALS AND METHODS

By searching the databases of PubMed and CNKI, we included all the published articles related serum p16 gene promoter methylation and nonsmall lung cancer. The true positive, false positive, false negative, and true negative data for each included publication were extracted by the reviewers. The diagnostic sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the receiver operating characteristic (ROC) were pooled by MetaDiSc1.4 software.

RESULTS

Finally, 13 manuscripts with 1440 subjects were involving in this diagnostic meta-analysis. The pooled sensitivity and specificity were 0.25 (95% confidence interval [CI]: 0.18-0.32) and 0.95 (95% CI: 0.93-0.97), respectively, with randomized effect model. The pooled positive likelihood ratio and negative likelihood ratio were 5.08 (95% CI: 3.00-8.62) and 0.69 (95% CI: 0.62-0.77) with fixed effect model and randomized effect model, respectively. The diagnostic ROC curve for the included 13 publications was pooled by statistical software MetaDiSc14.0 according to the Bayes theorem. The pooled area under the ROC was 0.72 with its standard error of 0.10.

CONCLUSION

According to the published articles, high specificity and low sensitivity were found in this meta-analysis for the p16 gene promoter methylation in the diagnosis of NSCLC.

Association of Cytochrome P450 Genetic Variants with Clopidogrel Resistance and Outcomes in Acute Ischemic Stroke

Aims: Clopidogrel is an antiplatelet drug primarily used to treat or prevent acute ischemic stroke (IS) or myocardial infarction (MI). This prodrug requires biotransformation to an active metabolite by cytochrome P450 (CYP) enzymes, and CYP single nucleotide polymorphisms (SNPs) could affect the efficiency of such biotransformation.

Methods: A total of 375 consecutive IS patients were genotyped for eight CYP SNPs using mass spectrometry. Platelet aggregation activity was measured before and after the 7 – 10 day treatment. Gene–gene interactions were analyzed using generalized multifactor dimensionality reduction (GMDR) analysis. All patients received clopidogrel therapy and were followed up for six months. Primary outcomes were evaluated as a composite of recurrent ischemic stroke (RIS), MI, and death. The secondary outcome was the modified Rankin Scale (mRS).

Results: Clopidogrel resistance occurred in 153 patients (40.8%). The frequency of CYP3A5 (rs776746) GG/AG and CYP2C19*2 (rs4244285) AA/AG genotypes was significantly higher in clopidogrel-resistant patients than in sensitive patients. There was a significant gene-gene interaction between CYP3A5 (rs776746) and CYP2C19*2 (rs4244285). CYP2C19*2 AA and its interaction with CYP3A5 GG were independent predictors of clopidogrel resistance and affected the activity of platelet aggregation. Diabetes mellitus, CYP2C19*2 (rs4244285), clopidogrel resistance, and the interaction of CYP2C19*2 with CYP3A5 were all independent risk factors for the primary outcomes of clopidogrel treatment. Clopidogrel-resistant patients were more likely to have poor outcomes (mRS > 2 points) compared with clopidogrel-sensitive patients.

Conclusion:CYP SNPs and their interactions are associated with drug resistance and outcomes in acute IS patients.

Cytochrome 4A11 Genetic Polymorphisms Increase Susceptibility to Ischemic Stroke and Associate with Atherothrombotic Events After Stroke in Chinese

To evaluate the associations between four single-nucleotide polymorphisms (SNPs) in CYP4A11 and CYP4F2 and ischemic stroke (IS), and between these variants and atherothrombotic events after stroke. IS patients (n=396) and controls (n=378) were genotyped for two CYP4A11 SNPs (rs2269231 and rs9333025) and two CYP4F2 SNPs (rs2108622 and rs3093135). Patients were followed up for 12 months after the stroke for the atherothrombotic events. The frequency of the rs9333025 GG genotype was significantly higher in IS patients than in controls. Logistic regression analysis showed that the presence of rs9333025 GG in patients was associated with significantly higher risk of IS. Cox regression analysis revealed that the rs9333025 GG genotype was an independent risk factor for atherothrombotic events after stroke. The rs9333025 GG genotype increases patients' susceptibility to IS and is associated with high frequencies of atherothrombotic events in stroke patients.

Genetic polymorphisms of ALOX5AP and CYP3A5 increase susceptibility to ischemic stroke and are associated with atherothrombotic events in stroke patients

BACKGROUND

The contributions of gene-gene interactions to pathogenesis of stroke remain largely elusive. The present study was designed to investigate the associations between genetic variations and ischemic stroke risk, the roles of gene-gene interactions in ischemic stroke, and their associations with atherothrombotic events.

METHODS

Among 396 patients with ischemic stroke and 378 controls, we examined 8 variants from 5 genes, including ALOX5AP-SG13S32 (rs9551963), SG13S42 (rs4769060), SG13S89 (rs4769874), SG13S114 (rs10507391), EPHX2 G860A (rs751141), CYP2C9*2 C430T (rs1799853), CYP2C9*3 A1075C (rs1057910), and CYP3A5 A6986G (rs776746), using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Gene-gene interactions were determined by the generalized multifactor dimensionality reduction (GMDR) method. All ischemic stroke patients were followed up 12 months for atherothrombotic events, including recurrent ischemic stroke and other vascular events.

RESULTS

Single-gene variant analysis showed no significant differences in the genotype distributions of the 8 variants between the 2 groups. However, the GMDR analysis showed a significant interaction between rs10507391 and rs776746, in those cases carrying rs10507391 AA and rs776746 GG, the risk of ischemic stroke increased by 2.014 times (95% confidence interval [CI], 1.896-6.299; P = .006), and the atherothrombotic events occurred more frequently in those patients during follow-up period (P < .001). Multiple Cox regression analysis showed that the interaction between rs10507391 AA and rs776746 GG was an independent risk factor for atherothrombotic events (relative risk = 2.921; 95% CI, 1.118-7.012; P = .008).

CONCLUSIONS

The interaction between rs10507391 and rs776746 increases the susceptibility to ischemic stroke and is associated with atherothrombotic events in stroke patients.

β-Catenin and NF-κB co-activation triggered by TLR3 stimulation facilitates stem cell-like phenotypes in breast cancer

Cancer stem cells (CSCs) are responsible for tumor initiation and progression. Toll-like receptors (TLRs) are highly expressed in cancer cells and associated with poor prognosis. However, a linkage between CSCs and TLRs is unclear, and potential intervention strategies to prevent TLR stimulation-induced CSC formation and underlying mechanisms are lacking. Here, we demonstrate that stimulation of toll-like receptor 3 (TLR3) promotes breast cancer cells toward a CSC phenotype in vitro and in vivo. Importantly, conventional NF-κB signaling pathway is not exclusively responsible for TLR3 activation-enriched CSCs. Intriguingly, simultaneous activation of both β-catenin and NF-κB signaling pathways, but neither alone, is required for the enhanced CSC phenotypes. We have further identified a small molecule cardamonin that can concurrently inhibit β-catenin and NF-κB signals. Cardamonin is capable of effectively abolishing TLR3 activation-enhanced CSC phenotypes in vitro and successfully controlling TLR3 stimulation-induced tumor growth in human breast cancer xenografts. These findings may provide a foundation for developing new strategies to prevent the induction of CSCs during cancer therapies.

Clopidogrel Plus Aspirin Prevents Early Neurologic Deterioration and Improves 6-Month Outcome in Patients With Acute Large Artery Atherosclerosis Stroke

Aims:

To evaluate the effects of treatments with clopidogrel plus aspirin (dual therapy) on early neurological deterioration (END) and outcomes at 6 months in patients with acute large artery atherosclerosis (LAA) stroke.

Methods:

A total of 574 patients with LAA stroke were randomly assigned to receive either dual therapy or aspirin alone (monotherapy). The primary outcome was END. Secondary outcomes included recurrent ischemic stroke (RIS) and outcomes at 6 months.

Results:

The prevalence of END and RIS was lower in patients on dual therapy than in those on monotherapy during the 30 days. At 6 months, dual therapy improved outcomes among older patients and those with symptomatic stenosis in the posterior circulation and basilar artery.

Conclusion:

Clopidogrel plus aspirin is superior to aspirin alone for reducing END and RIS within 30 days and improves outcomes in certain subgroups at 6 months.

An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children

Children with low aerobic fitness have altered brain function compared to higher-fit children. This study examined the effect of an 8-month exercise intervention on resting state synchrony. Twenty-two sedentary, overweight (body mass index ≥85th percentile) children 8-11 years old were randomly assigned to one of two after-school programs: aerobic exercise (n=13) or sedentary attention control (n=9). Before and after the 8-month programs, all subjects participated in resting state functional magnetic resonance imaging scans. Independent components analysis identified several networks, with four chosen for between-group analysis: salience, default mode, cognitive control, and motor networks. The default mode, cognitive control, and motor networks showed more spatial refinement over time in the exercise group compared to controls. The motor network showed increased synchrony in the exercise group with the right medial frontal gyrus compared to controls. Exercise behavior may enhance brain development in children.

The effects of angiotensin-converting enzyme-inhibitory peptide LAP on the left common carotid artery remodeling in spontaneously hypertensive rats

OBJECTIVE

To investigate the protective effect of angiotensin-converting enzyme (ACE)-inhibitory peptide LAP on the left common carotid artery remodeling in spontaneously hypertensive rats (SHRs).

METHODS

A cohort of male SHRs were randomly divided into three groups (n = 10 for each group): pseudo-experimental group, enalapril-treated group as a positive control group, ACE-inhibitory peptide LAP-treated group. After the experiment, the left common carotid artery from each rat was removed for morphological evaluation.

RESULTS

It was observed that the vascular medial thickness, media thickness/lumen diameter, medial cross-sectional area and mean nuclear area of smooth muscle cells of the left common carotid artery in the LAP group or enalapril group were significantly lower than those in the pseudo-experimental group, while there was no significant difference in these parameters observed between the LAP group and enalapril group. Additionally, the vascular area percentage of collagen fibers of the left common carotid artery in the LAP group and enalapril group was significantly lower than that of the pseudo-experimental group.

CONCLUSIONS

The protective vessel remodeling effect in SHRs was observed with ACE-inhibitory peptide LAP in SHRs by decreasing blood pressure, inhibiting smooth muscle cell hypertrophy and reducing the proliferation of collagen fibers.

Platelet response to aspirin in Chinese stroke patients is independent of genetic polymorphisms of COX-1 C50T and COX-2 G765C

AIM

Aspirin resistance (AR) is common in Chinese stroke patients taking antiplatelet medications; however, few studies have documented the role of cyclooxygenase (COX)-1 C50T and COX-2 G765C polymorphisms in AR. The aim of this study was to investigate the prevalence of AR in Chinese stroke patients and the relationships between AR and COX-1 C50T and COX-2 G765C polymorphisms, and to evaluate the effect of these polymorphisms on platelet response to aspirin.

METHODS

We prospectively enrolled 634 Chinese stroke patients. Platelet aggregation testing was performed before and after aspirin administration. The pre- and post-aspirin levels of 11-dehydrothromboxane B(2) (11-dTxB(2)) were determined in urine samples. COX-1 C50T and COX-2 G765C genotypes were determined by a polymerase chain reaction-allelic restriction assay.

RESULTS

AR was detected in 129 patients (20.4%), aspirin semi-resistance (ASR) was detected in 28 patients (4.4%), and aspirin sensitivity (AS) was detected in 477 patients (75.2%). There was no association between COX-1 C50T or COX-2 G765C polymorphisms and ASR+AR. Aspirin could efficiently reduce 11-dTxB(2) production by approximately 75%. In addition, platelet aggregation, both in response to arachidonic acid (AA) and adenosine 5'-diphosphate (ADP), was inhibited by more than 80% and 40%, respectively; however, the percentage reduction in platelet aggregation and 11-dTxB(2) levels was not significantly different between the COX-1 C50T and COX-2 G765C genotypes (p＞0.05).

CONCLUSIONS

There was no association between COX-1 C50T and COX-2 G765C polymorphisms and AR in Chinese stroke patients. In addition, COX-1 C50T and COX-2 G765C polymorphisms had no effect on the platelet response to aspirin.

Electronic structure of spatially aligned graphene nanoribbons on Au(788)

We report on a bottom-up approach of the selective and precise growth of subnanometer wide straight and chevron-type armchair nanoribbons (GNRs) on a stepped Au(788) surface using different specific molecular precursors. This process creates spatially well-aligned GNRs, as characterized by STM. High-resolution direct and inverse photoemission spectroscopy of occupied and unoccupied states allows the determination of the energetic position and momentum dispersion of electronic states revealing the existence of band gaps of several electron volts for straight 7-armchair, 13-armchair, and chevron-type GNRs in the electronic structure.

Hypoxia inducible factor promotes murine allergic airway inflammation and is increased in asthma and rhinitis

BACKGROUND

New therapies are necessary to address inadequate asthma control in many patients. This study sets out to investigate whether hypoxia-inducible factor (HIF) is essential for development of allergic airway inflammation (AAI) and therefore a potential novel target for asthma treatment.

METHODS

Mice conditionally knocked out for HIF-1β were examined for their ability to mount an allergic inflammatory response in the lung after intratracheal exposure to ovalbumin. The effects of treating wild-type mice with either ethyl-3,4-dihydroxybenzoate (EDHB) or 2-methoxyestradiol (2ME), which upregulate and downregulate HIF, respectively, were determined. HIF-1α levels were also measured in endobronchial biopsies and bronchial fluid of patients with asthma and nasal fluid of patients with rhinitis after challenge.

RESULTS

Deletion of HIF-1β resulted in diminished AAI and diminished production of ovalbumin-specific IgE and IgG(1) . EDHB enhanced the inflammatory response, which was muted upon simultaneous inhibition of vascular endothelial growth factor (VEGF). EDHB and 2ME antagonized each other with regard to their effects on airway inflammation and mucus production. The levels of HIF-1α and VEGF increased in lung tissue and bronchial fluid of patients with asthma and in the nasal fluid of patients with rhinitis after challenge.

CONCLUSIONS

Our results support the notion that HIF is directly involved in the development of AAI. Most importantly, we demonstrate for the first time that HIF-1α is increased after challenge in patients with asthma and rhinitis. Therefore, we propose that HIF may be a potential therapeutic target for asthma and possibly for other inflammatory diseases.

Identification of craniofacial risk factors for obstructive sleep apnoea using three-dimensional MRI

The alteration of craniofacial structures has been associated with obstructive sleep apnoea (OSA). We hypothesised that: 1) a smaller mandible is a risk factor for OSA; and 2) the previously observed inferiorly positioned hyoid bone in apnoeics is associated with enlarged tongue volume. This is a case-control study using three-dimensional magnetic resonance imaging cephalometry. 55 apneics and 55 controls were matched for age, sex and race. The analysis was stratified by sex and controlled for age, race, height, neck visceral fat, skeletal type and tongue volume. We found that a 1-sd increase in mandibular length and depth were associated with decreased risk of sleep apnoea (OR 0.52, 95% CI 0.28-0.99 and OR 0.46, 95% CI 0.23-0.91, respectively) in males but not in females. Greater hyoid-to-nasion (OR 2.64, 95% CI 1.19-5.89 in males and OR 5.01, 95% CI 2.00-12.52 in females) and supramentale-to-hyoid (OR 2.39, 95% CI 1.12-5.14) in males and OR 3.38, 95% CI 1.49-7.68 in females) distances were associated with increased risk of OSA. The difference for hyoid position between apnoeics and controls was lost after controlling for tongue volume. Enlargement of tongue is likely to be the pathogenic factor for inferior-posterior positioning of hyoid. A small and shallow mandible is an independent risk factor for OSA in males but not in females.

Hypertension and albuminuria in chronic kidney disease mapped to a mouse chromosome 11 locus

Chronic kidney disease (CKD) is a key cause of hypertension and a potent independent risk for cardiovascular disease. Epidemiological studies suggest a strong genetic component determining susceptibility for renal disease and, by inference, the associated cardiovascular risk. With a subtotal nephrectomy model of kidney disease, we found the 129S6 mouse strain to be very susceptible to the development of hypertension, albuminuria, and kidney injury, whereas the C57BL/6 strain is relatively resistant. Accordingly, we set out to map quantitative trait loci conferring susceptibility to hypertension and albuminuria using this model with F2 mice. We found significant linkage of the blood pressure trait to two loci. At D11Mit143, mice homozygous for the 129S6 allele had significantly higher systolic blood pressure than mice heterozygous or homozygous for the C57BL/6 allele. Similarly, at D1Mit308, there was an excellent correlation between genotype and the blood pressure phenotype. The effect of the chromosome 11 locus was verified with a separate cohort of F2 mice. For the albuminuria trait, a significant locus was found at D11Mit143, which overlaps the blood pressure trait locus. Our studies have identified a region spanning approximately 8 cM on mouse chromosome 11 that is associated with susceptibility to hypertension and albuminuria in CKD.

Hyperdense intracranial epidermoid cysts: a study of 15 cases

BACKGROUND

Although intracranial epidermoid cysts generally appear as hypodense lesions on CT scans, occasionally, they may appear hyperdense, making diagnosis difficult. The aim was to study clinical features and possible pathogenesis of hyperdense intracranial epidermoid cysts (HIECs).

METHODS

Fifteen patients with HIECs were surgically treated in our department during a 21-year period (1985 up to 2005). We reviewed each patient's clinical records, radiological findings, operative reports, and pathological examinations, along with a review of the literature.

FINDINGS

The incidence of HIECs in our series was approximately 3.02%, with female predominance. The average age was 32 years and the average duration of complaints was nine months. The most common location was the parasellar area (6 cases), followed by cerebellum (4 cases), clival region (3 cases), cerebello-pontine angle (1 case) and lateral ventricle (1 case). Gross-total excision of the tumor was achieved in ten patients (66.7%). Four (26.7%) patients underwent subtotal resection; and one (6.6%) patient underwent partial resection. Aseptic meningitis that occurred postoperatively in two cases was controlled by lumbar drainage.

CONCLUSIONS

Recurrent leakage of the irritating cyst contents and subsequent chemical inflammatory response may be responsible for the high-density on CT scans and the cystic nature. A correct histological diagnosis is important because, in contrast to typical ECs and other lesions, HIECs are more prone to spread intra-operatively and result in severe aseptic meningitis.

Inhibitors of blood coagulation factors Xa and IIa synergize to reduce thrombus weight and thrombin generation in vivo and in vitro

BACKGROUND

Many compounds currently in development for treatment of thrombotic disorders demonstrate high specificity for single targets of blood coagulation such as factor Xa (FXa) or thrombin.

AIM

The aim of this study is to determine if inhibition of both FXa and thrombin by simultaneous administration of PD0313052 and argatroban, respectively, synergistically increases the effect of either drug alone in vivo and in vitro.

METHODS AND RESULTS

Analyses of thrombin generation from combined inhibition in human plasma using statistical methods of Bliss independence identified a synergistic reduction in thrombin production 30% lower than predicted by simple additivity. The greatest synergy occurred at concentrations of each compound below their individual IC50 values. In a rabbit arterio-venous shunt model (RAV) of thrombosis, co-administration of PD0313052 and argatroban reduced thrombus weight (TW) to a much greater degree than expected by additivity alone producing a synergistic decrease of 45% over the level predicted by additivity. Analyses of thrombin generation in plasma samples from the RAV also demonstrated 38% synergy ex vivo. Furthermore, at plasma concentrations with the greatest synergistic effect, no increase in bleeding or appreciable change in prothrombin time, activated partial thromboplastin time, or activated clotting time was observed, but thrombus weight reduction was greater than twofold higher than that expected from simple additivity.

CONCLUSIONS

These results demonstrate a significant synergistic antithrombotic effect of combining low doses of PD0313052 and argatroban and support the hypothesis that simultaneous targeting of multiple coagulation enzymes may offer an improved therapeutic index in the prevention and treatment of thrombosis.

Increased production of reactive oxygen species contributes to motor neuron death in a compression mouse model of spinal cord injury

STUDY DESIGN

Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury.

OBJECTIVES

To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury.

SETTING

University of Louisville Health Science Center.

METHODS

Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury.

RESULTS

ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury.

CONCLUSION

These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.

The therapeutic potential of novel anticoagulants

Conventional anticoagulant therapy has been based on indirect inhibition of coagulation factors with heparin and warfarin. These agents display liabilities prompting the development of new anticoagulants over the last two decades. The first to be developed was a series of low molecular weight heparins(LMWHs). Their favourable pharmacokinetic profiles and risk/benefit ratios led to widespread use in Europe and, more recently, approval for their use in the USA. Paralleling the development of LMWHs has been the pursuit of a different strategy focused on direct rather than indirect inhibition of enzymes in the coagulation cascade. In contrast to heparin, LMWHs, or other glycosaminoglycans, direct inhibitors exert their effects independent of either antithrombin III (ATIII) or heparin cofactor II (HCII) and more effectively inhibit clot-bound thrombin or FXa. Highly potent, selective (versus other serine proteases)direct thrombin and FXa inhibitors have been identified and isolated from natural sources, such as leeches, ticks and hookworms. The recombinant forms and analogues of the senatural proteins have been produced using molecular biology techniques, i.e., rHirudin, Hirulogs, recombinant tick anticoagulant peptide (rTAP), recombinant antistasin (rATS) and recombinant nematode anticoagulant peptide-5 (rNAP-5). The design of novel structures or the modification of existing chemicals has led to the synthesis of many non-peptide, low molecular weight inhibitors of thrombin and FXa. Some of them are orally active and may be suitable for long-term clinical use. In addition, considerable progress has been made in developing specific TF/VIIa complex inhibitors. The anticoagulation properties of the new agents are being characterised in experimental studies. Some of them have been advanced to large scale clinical trials and their effectiveness, and sometimes relative ineffectiveness,in arterial and venous thromboembolic disorders has been demonstrated. They are being tested for their potential as new antithrombotic agents that act via direct enzyme inhibition. Thus,the clinician should in future be able to target different thrombotic conditions with proven, specific anticoagulant interventions.

Characterization of a tissue factor/factor VIIa-dependent model of thrombosis in hypercholesterolemic rabbits

Tissue factor (TF) expressed in arterial atherosclerotic plaque plays a key role in activating the extrinsic coagulation pathway and triggering acute coronary syndromes. In this study, we developed and characterized a TF-factor (F)VIIa-mediated thrombosis model in rabbits. Balloon catheter-induced endothelial denudation in the femoral artery and a 4-week high cholesterol diet produced a localized atherosclerotic plaque at the injured site. High levels of TF mRNA and TF protein antigen (152 +/- 25 vs. 49 +/- 12 pg mg-1 protein in normal vessels) were detected in these atherosclerotic plaques. Plasma FVII coagulant activity (FVII:C) was significantly increased in the hypercholesterolemic rabbits (36 +/- 1 s) compared with the normal rabbits (44 +/- 1 s, P < 0.0001). Plaque rupture was induced by balloon angioplasty, which resulted in thrombus formation in the injured vessel segment after a brief period of stasis. FVIIai, a specific TF-FVIIa inhibitor, was administered intravenously to rabbits before plaque rupture at 0.3 and 1.0 mg kg-1. FVIIai dose-dependently reduced thrombus mass (14.7 +/- 2.5 and 5.9 +/- 2.2 mg, respectively, vs. 21.6 +/- 1.9 mg in the control group). PD198961, a novel factor Xa inhibitor, and argatroban, a thrombin inhibitor, also dose-dependently inhibited thrombosis. These results indicate that thrombus formation in this model is initiated by the activation of TF-FVIIa pathway, which is attributed to TF expression in the atherosclerotic plaque and enhanced plasma FVII coagulant activity. This model may be useful for evaluating in vivo efficacy of new antithrombotic drugs, particularly TF-FVIIa inhibitors.

Increased oxidative stress is associated with chronic intermittent hypoxia-mediated brain cortical neuronal cell apoptosis in a mouse model of sleep apnea

Chronic intermittent hypoxia (CIH), as occurs in obstructive sleep apnea (SA), is associated with substantial cortico-hippocampal damage leading to impairments of neurocognitive, respiratory and cardiovascular functions. Previous studies in a rat model have shown that CIH increases brain cortical neuronal cell death. However, the molecular events leading to CIH-mediated neuronal cell death remain largely undefined. The oscillation of O2 concentrations during CIH remarkably mimics the processes of ischemia/re-oxygenation and could therefore increase cellular production of reactive oxygen species (ROS). We extended the CIH paradigm to a mouse model of SA to identify the molecular mechanisms underlying cortical neuronal cell death. A significant increase of ROS production in mouse brain cortex and cortical neuronal cells was detected by fluorescent oxidation assays upon exposure of mice to CIH, followed by increased expression of oxidative stress response markers, c-Fos, c-Jun and NF-kappaB in mouse brain cortex, as revealed by immunohistochemical and LacZ reporter assays respectively. Long-term exposure of mice to CIH increased the levels of protein oxidation, lipid peroxidation and nucleic acid oxidation in mouse brain cortex. Furthermore, exposure of mice to CIH induced caspase-3 activation and increased some cortical neuronal cell apoptosis. On the other hand, transgenic mice overexpressing Cu,Zn-superoxide dismutase exposed to CIH conditions had a lower level of steady-state ROS production and reduced neuronal apoptosis in brain cortex compared with that of normal control mice. Taken together, these findings suggest that the increased ROS production and oxidative stress propagation contribute, at least partially, to CIH-mediated cortical neuronal apoptosis and neurocognitive dysfunction.

Nanostructured dna-protein aggregates consisting of covalent oligonucleotide-streptavidin conjugates

Covalent conjugates consisting of streptavidin and a 24-mer single-stranded DNA oligonucleotide have been oligomerized by cross-linking with a 5',5'-bis-biotinylated 169-base-pair double-stranded DNA (dsDNA) fragment. The oligomeric conjugates formed have been analyzed by nondenaturing gel electrophoresis and scanning-force microscopy (SFM). The comparison of analogous oligomers, prepared from native STV and the bis-biotinylated dsDNA fragment, revealed that the covalent STV-oligonucleotide hybrid conjugates self-assemble to generate oligomeric aggregates of significant smaller size, containing on average only about 2.5 times less dsDNA fragments per aggregate. Likely, this is a consequence of electrostatic or steric repulsion between the dsDNA and the single-stranded oligomer covalently attached to the hybrid, as indicated from control experiments. Nevertheless, the single-stranded oligonucleotide moiety within the oligomeric conjugates can be used as a selective molecular handle for further functionalization and manipulation. For instance, it was used for specific DNA-directed immobilization at a surface, previously functionalized with complementary capture oligonucleotides. Moreover, we demonstrate that macromolecules, such as STV and antibody molecules, which are tagged with the complementary oligonucleotide, specifically bind to the supramolecular DNA-STV oligomeric conjugates. This leads to a novel class of functional DNA-protein conjugates, suitable, for instance, as reagents in immuno-PCR or as building blocks in molecular nanotechnology.