Electric-field variations within a nematic-liquid-crystal layer

A thin layer of nematic liquid crystal (NLC) across which an electric field is applied is a setup of great industrial importance in liquid crystal display devices. There is thus a large literature modeling this situation and related scenarios. A commonly used assumption is that an electric field generated by electrodes at the two bounding surfaces of the layer will produce a field that is uniform: that is, the presence of NLC does not affect the electric field. In this paper, we use calculus of variations to derive the equations coupling the electric potential to the orientation of the NLC's director field, and use a simple one-dimensional model to investigate the limitations of the uniform field assumption in the case of a steady applied field. The extension of the model to the unsteady case is also briefly discussed.

Androgen receptor functions in castration-resistant prostate cancer and mechanisms of resistance to new agents targeting the androgen axis

The metabolic functions of androgen receptor (AR) in normal prostate are circumvented in prostate cancer (PCa) to drive tumor growth, and the AR also can acquire new growth-promoting functions during PCa development and progression through genetic and epigenetic mechanisms. Androgen deprivation therapy (ADT, surgical or medical castration) is the standard treatment for metastatic PCa, but patients invariably relapse despite castrate androgen levels (castration-resistant PCa, CRPC). Early studies from many groups had shown that AR was highly expressed and transcriptionally active in CRPC, and indicated that steroids from the adrenal glands were contributing to this AR activity. More recent studies showed that CRPC cells had increased expression of enzymes mediating androgen synthesis from adrenal steroids, and could synthesize androgens de novo from cholesterol. Phase III clinical trials showing a survival advantage in CRPC for treatment with abiraterone (inhibitor of the enzyme CYP17A1 required for androgen synthesis that markedly reduces androgens and precursor steroids) and for enzalutamide (new AR antagonist) have now confirmed that AR activity driven by residual androgens makes a major contribution to CRPC, and led to the recent Food and Drug Administration approval of both agents. Unfortunately, patients treated with these agents for advanced CRPC generally relapse within a year and AR appears to be active in the relapsed tumors, but the molecular mechanisms mediating intrinsic or acquired resistance to these AR-targeted therapies remain to be defined. This review outlines AR functions that contribute to PCa development and progression, the roles of intratumoral androgen synthesis and AR structural alterations in driving AR activity in CRPC, mechanisms of action for abiraterone and enzalutamide, and possible mechanisms of resistance to these agents.

Selective approach to thioesters and thioethers via sp3 C–H activation of methylarenes

Novel CDC approaches for the synthesis of thioesters and thioethers was developed via sp³ C–H activation of methylarenes and subsequent functionalization.

Bifurcation properties of nematic liquid crystals exposed to an electric field: switchability, bistability, and multistability

Bistable liquid crystal displays (LCDs) offer the potential for considerable power savings compared with conventional (monostable) LCDs. The existence of two (or more) stable field-free states that are optically distinct means that contrast can be maintained in a display without an externally applied electric field. An applied field is required only to switch the device from one state to the other, as needed. In this paper we examine the basic physical principles involved in generating multiple stable states and the switching between these states. We consider a two-dimensional geometry in which variable surface anchoring conditions are used to control the steady-state solutions and explore how different anchoring conditions can influence the number and type of solutions and whether or not switching is possible between the states. We find a wide range of possible behaviors, including bistability, tristability, and tetrastability, and investigate how the solution landscape changes as the boundary conditions are tuned.

[Radioactive seed implantation for the treatment of mediastinal malignant tumors and lymph node metastases in 43 cases]

背景与目的

纵隔内恶性肿瘤位置深邃、隐匿, 手术切除可能性极小。由于其紧邻心包、主气管、大血管等重要解剖结构, 氩氦刀冷冻及热消融同样受到限制。本文比较43例放射性¹²⁵Ⅰ粒子植入患者的影像复查资料和生存质量, 探讨其操作安全性和临床疗效。

方法

2010年7月-2011年7月经病理证实并完成随访的43例患者, 其中原发纵隔型肺鳞癌21例, 原发食管癌9例, 淋巴结转移癌13例。合并主气道50%以上狭窄18例, 食管梗阻9例, 上腔静脉回流障碍6例。每个病灶植入¹²⁵Ⅰ粒子10枚-60枚, 平均(30.79±14.23)枚。治疗后2个月、4个月、6个月及12个月复查CT观察局部病灶控制情况, 并对患者生存质量及生存期进行随访。

结果

全部操作技术成功率100%, 最长随访时间12个月, 6个月生存37例, 6个月生存率为85.0%, 局部病灶PR 30个, NC 7个, 临床有效率为81.08%, 临床受益率为100%。12个月生存31例, 1年生存率为60.5%, 局部病灶CR 16个, PR 7个, NC 2个, PD 6个, 临床有效率为74.19%, 临床受益率为80.65%。6个月、12个月KPS评分提高且差异明显。穿刺导致气胸3例(6.98%), 无大血管、主气管、喉返神经及心包损伤等严重并发症。

结论

放射性¹²⁵Ⅰ粒子植入治疗纵隔内恶性肿瘤, 技术成功率高且相对安全, 临床疗效肯定。

Prevention and treatment of DNA vaccine encoding cockroach allergen Bla g 1 in a mouse model of allergic airway inflammation

BACKGROUND

One-fourth of the US population is sensitized to the German cockroach. Primary German cockroach allergen Bla g 1 is detected in 63% of homes and 52% of childcare facilities in the United States. No effective treatment or vaccination strategies are yet available.

OBJECTIVES

We evaluated the prophylactic and therapeutic efficacy of a plasmid DNA-mediated vaccination using the Bla g 1 gene in a mouse model of allergic inflammatory airway disease.

METHODS

A plasmid DNA vector coding for the Bla g 1 allergen controlled by cytomegalovirus promoter was constructed. To estimate the protective efficacy, BALB/c mice were given three injections of plasmid DNA-Bla g 1 prior to sensitization with two priming doses of recombinant Bla g 1 (rBla g 1) antigens, followed by nebulized rBla g 1 challenge. In the therapeutic approach, sensitization was followed by administering Bla g 1 DNA vaccine.

RESULTS

Bla g 1 vaccination significantly reduced allergen-induced airway inflammation, even after mice were presensitized and a Th2-dominant response was established. The Bla g 1 vaccination significantly reduced total inflammatory cell infiltrate, eosinophilia, secretion of Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, allergen-induced inflammatory infiltrates in the lungs, and Bla g 1-specific IgE in serum upon challenge with rBla g 1. Importantly, Bla g 1 DNA vaccination was able to induce IL-10-secreting regulatory T cells that could suppress the allergen-specific Th2 cells.

CONCLUSION

DNA vaccination showed protective and therapeutic efficacy against a clinically relevant allergen Bla g 1.

The use of phenome-wide association studies (PheWAS) for exploration of novel genotype-phenotype relationships and pleiotropy discovery

The field of phenomics has been investigating network structure among large arrays of phenotypes, and genome-wide association studies (GWAS) have been used to investigate the relationship between genetic variation and single diseases/outcomes. A novel approach has emerged combining both the exploration of phenotypic structure and genotypic variation, known as the phenome-wide association study (PheWAS). The Population Architecture using Genomics and Epidemiology (PAGE) network is a National Human Genome Research Institute (NHGRI)-supported collaboration of four groups accessing eight extensively characterized epidemiologic studies. The primary focus of PAGE is deep characterization of well-replicated GWAS variants and their relationships to various phenotypes and traits in diverse epidemiologic studies that include European Americans, African Americans, Mexican Americans/Hispanics, Asians/Pacific Islanders, and Native Americans. The rich phenotypic resources of PAGE studies provide a unique opportunity for PheWAS as each genotyped variant can be tested for an association with the wide array of phenotypic measurements available within the studies of PAGE, including prevalent and incident status for multiple common clinical conditions and risk factors, as well as clinical parameters and intermediate biomarkers. The results of PheWAS can be used to discover novel relationships between SNPs, phenotypes, and networks of interrelated phenotypes; identify pleiotropy; provide novel mechanistic insights; and foster hypothesis generation. The PAGE network has developed infrastructure to support and perform PheWAS in a high-throughput manner. As implementing the PheWAS approach has presented several challenges, the infrastructure and methodology, as well as insights gained in this project, are presented herein to benefit the larger scientific community.

Mitochondrial DNA mutations in head and neck cancer are infrequent and lack prognostic utility

Background:

Mitochondrial DNA (mtDNA) mutations occur in head and neck squamous cell carcinoma (HNSCC) and are most frequently detected in the displacement-loop (D-loop) region. The D-loop is considered to be important because it controls mitochondrial gene expression and mtDNA replication. There is currently no evidence that mtDNA mutations can be used as prognostic or predictive biomarkers in HNSCC.

Methods:

We used denaturing high performance liquid chromatography to screen the entire mitochondrial genome of six oral squamous cell carcinoma-derived cell lines and then focused on detecting D-loop abnormalities in 34 HNSCC tissue samples.

Results:

Mitochondrial DNA mutations are not ubiquitous in HNSCC because only half of the cell lines had detectable mtDNA abnormalities following screening of the entire mitochondrial genome and only 18% (6 of 34) of tissue samples had D-loop mutations. There was no correlation between D-loop mutations and determinates of clinical outcome; specifically, tumour stage and the expression of hypoxia-inducible genes included in a highly prognostic hypoxia metagene.

Conclusions:

Taken together, these data suggest that mtDNA D-loop mutations are stochastic events that may not significantly influence the biology of HNSCC and supports the hypothesis that mtDNA mutations in cancer represent bystander genotoxic damage as a consequence of tumour development and progression.

Leptin as clinical target

PLeptin is an adipocyte-derived hormone with pleiotropic effects on energy homeostasis, endocrine and reproductive functions, and immune responses. The multiple actions of leptin have led to the design and development of several leptin-based approaches to modulate the metabolic and endocrine status, to reduce inflammation, and to improve immune responses. Here, we review the current patents on leptin in different clinic applications.

Critical moisture content windows differ for the cryopreservation of pomelo (Citrus grandis) seeds and embryonic axes

Cryopreservation was attempted using a partial dehydration and freezing protocol on pomelo (Citrus grandis) seeds of ten cultivars and embryonic axes of one cultivar collected from Xishuangbanna. Although seeds of all ten cultivars could be dehydrated safely to 10 percent moisture content, further dehydration impaired seed viability with critical moisture contents ranging from 9 percent to 7 percent. Complete seedling regenerated from seeds frozen in a moisture window between 5-9 percent, and maximum seedling recovery varied between 22-86 percent. Cryopreservation of Jiajieyou cv. embryonic axes had a moisture window between 3-20 percent , much wider compared to whole seed cryopreservation, and maximum post-thaw emergence of 93 percent was achieved at 13 percent moisture content. Emergence differed only slightly from survival when whole seeds were cryopreserved, but for the embryonic axis cryopreservation at low moisture contents resulted in much lower emergence than survival. Possible causes of intraspecific variation in cryotolerance in pomelo seeds is discussed.

Giant congenital melanocytic nevus coexistent with Chiari II malformation

BACKGROUND

Giant congenital melanocytic nevus (GCMN) and Chiari II malformation (CM II) are distinct rare clinical entities. No previous report of this condition is to be found in the medical literature.

MATERIAL AND METHODS

We report the case of a male infant seen initially for a GCMN and an upper thoracic myelomeningocele. MRI incidentally revealed cerebellum and brain stem elongate via the foramen magnum. The infant's physical examination included spastic quadriparesis and hypotonia. An operation for myelomeningocele repair and suboccipital craniectomy with resection of C (1) and cerebellar tonsils was done. The signs and symptoms of the patient were improved after surgery. The GCMN was not treated according to the parents' wished, but a schedule of long-term monitoring was recommended.

CONCLUSION

This case report illustrates that CMNs can coexist with CM II. The clinician who diagnoses a patient with CMNs should remember that this entity can be associated with other pathologies of the central nervous system. Earlier diagnosis and surgical intervention improves the prognosis. Long-term monitoring and follow-up should be recommended for patients with CMNs.

Prior SO2 exposure promotes airway inflammation and subepithelial fibrosis following repeated ovalbumin challenge

BACKGROUND

Exposure to allergens or air pollutants often leads to asthma exacerbations associated with aggravation of airway inflammation. Although, repeated allergen challenge often induces chronic allergic airway inflammation (CAAI) and airway remodelling, yet, the effects of brief exposure to air pollutants such as SO(2) on development of CAAI and airway remodelling remain to be clarified.

OBJECTIVE

The aim of the experiment was to investigate the effects of acute neutrophilic airway inflammation induced by brief exposure to SO(2) on development of CAAI and subepithelial fibrosis (SEF) in a murine model of asthma.

METHODS

Acute airway inflammation was induced by brief exposure to 50 p.p.m. SO(2) (1 h/d, 3 days). CAAI and SEF in BALB/c mice were induced by repeated challenge with ovalbumin (OVA) for 5 or 9 weeks with or without prior exposure to SO(2). Bronchoalveolar lavage fluid (BALF) eosinophilia as index of CAAI, BALF endothelin-1 (ET-1) and TGF-beta1 levels, morphometric evaluation of fibrotic area beneath subbasement membrane and lung hydroxyproline content (Hyp) as indexes of SEF were monitored.

RESULTS

Exposure to SO(2) led to acute neutrophilic inflammation and epithelial sloughing with profound elevation of BALF ET-1. Repeated OVA challenge resulted in CAAI and SEF along with elevation of Hyp, increase of fibrotic area beneath subbasement membrane and elevation of BALF TGF-beta1. Preceding SO(2) exposure exaggerated BALF eosinophilia, facilitated and enhanced SEF with more significant elevation of BALF ET-1 and TGF-beta1 levels compared with OVA-challenged mice without prior exposure to SO(2). The increase of Hyp was positively correlated with elevation of BALF TGF-beta1 during CAAI (r=0.842, P<0.01).

CONCLUSION

This data demonstrated that SEF developed in parallel with severity and time course of CAAI following repeated OVA challenge. SO(2)-induced acute epithelial injury and neutrophilic inflammation could enhance CAAI and promote SEF, probably through overexpression of ET-1 and TGF-beta1.

Chiari malformation caused by craniometaphyseal dysplasia: case report and review of literature

Chiari malformation is commonly considered a congenital condition. To our knowledge, reports of progressively symptomatic Chiari Iota malformation with craniometaphyseal dysplasia are rare. The authors present a case of progressively symptomatic Chiari Iota malformation occurring in an 11-month-old infant with craniometaphyseal dysplasia. The patient presented with a typical facial appearance and radiological skeletal survey. Posterior fossa decompression was performed. In the meantime, the patient was given Rocaltrol (calcitriol) and adopted a low calcium diet. His neurological symptoms were markedly improved after surgery. The clinical presentations, radiographical features and prognosis of the patient are discussed with reference to the literature.