One Methylene Group in the Side Chain Can Alter by 90 Degrees the Orientation of a Main-Chain Liquid Crystal on a Unidirectional Substrate

The mechanisms of orientation of columnar liquid crystals (LCs) on PTFE-rubbed surface are explored on a homologous series of symmetrically-substituted poly(di-n-alkylsiloxanes) (PDAS). It is shown that by increasing the side-chain length in steps of one CH2 group the orientation of PDAS switches back and forth from perpendicular to parallel with respect to PTFE chains. These changes sensitive to the smallest possible variation of the macromolecular structure (i.e., modification of the side chain length by just one CH2 group) reflect the change of the alignment mechanism identified as grapho-epitaxial or epitaxial for the perpendicular and parallel orientation, respectively. The results show that two orthogonal LC orientations are realizable on the same rubbed substrate, which can open new perspectives in the field of organic and printed electronics such as multi-domain LCD technology

Human papillomavirus infection in honduran women with normal cytology

Contains fulltext : 80440.pdf (publisher's version ) (Closed access)OBJECTIVE: This study was aimed at estimating type-specific HPV prevalence and its cofactors among Honduran women with normal cytology in order to provide valuable information to health policymakers about the epidemiology of this important sexually transmitted infection. METHODS: A total of 591 women with normal cytology from Tegucigalpa, Honduras were interviewed and tested for HPV using the SPF10 LiPA25. A structured epidemiological questionnaire was administered to each woman. RESULTS: The overall HPV prevalence was 51%. Twenty-three types of HPV were detected; HPV 16, 51, 31, 18, and 11 were the most common. The highest prevalence of cancer associated HPV types (15.0%) was found in the women less than 35 years. Besides the association with age, the main independent predictors of HPV infection were the lifetime number of sexual partners and having a low socioeconomic status and less than 5 previous Pap smears. CONCLUSIONS: In the population studied, there was a broad diversity of HPV infections, with high-risk types being the most common types detected. The establishment of a well-characterized population with regard to the community prevalence of type-specific HPV infection will provide a valuable baseline for monitoring population effectiveness of an HPV vaccine

Comparison of prevalence, viral load, physical status and expression of human papillomavirus-16, -18 and -58 in esophageal and cervical cancer: a case-control study

Background: Human papillomavirus (HPV) infection is a major risk factor for the development of nearly all cases of cervical cancer worldwide. The presence of HPV DNA in cases of esophageal squamous-cell carcinoma (ESCC) has been reported repeatedly from Shantou, China, and other regions with a high incidence of esophageal carcinoma (EC). However, unlike in cervical squamous-cell carcinoma (CSCC), in ESCC, the characteristics of HPV are unclear. Thus, the role of high-risk HPV types in the carcinogenesis of ESCC remains uncertain. Methods: Seventy cases of ESCC with 60 controls and 39 cases of CSCC with 54 controls collected from patients in Shantou region in China were compared for the distributions of HPV-16, -18 and -58; viral load; and viral integration using real-time PCR assay and HPV-16 expression using immunostaining. Results: The detection rates and viral loads of HR-HPV infection were significantly lower in ESCC than in CSCC (50.0% vs. 79.48%, P = 0.005; 2.55 +/- 3.19 vs. 361.29 +/- 441.75, P = 0.002, respectively). The combined integration level of HPV-16, -18 and -58 was slightly lower in ESCC than in CSCC (P = 0.022). HPV-16 expression was detected in 59.26% of ESCC tissue and significantly associated with tumour grade (P = 0.027). Conclusions: High levels of HR-HPV expression and integration may be an indicator of the risk of ESCC, at least for patients in the Shantou region of China. However, a relatively low HPV copy number and infection rate in ESCC is unlikely to play an essential a role in the carcinogenesis of ESCC as in cervical cancer. Factors other than HR-HPV infection may contribute to the carcinogenesis of ESCC.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000285251600001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701OncologySCI(E)26ARTICLEnull1

Simian Varicella Virus Infection of Rhesus Macaques Recapitulates Essential Features of Varicella Zoster Virus Infection in Humans

Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation

Effects of neuroinflammation on demyelination and remyelination: an in vitro study in aggregating brain cell cultures

La neuroinflammation joue un rôle important dans de nombreuses maladies neurodégéneratives dont la sclérose en plaques. Les microglies et les astrocytes sont les cellules effectrices de la réponse inflammatoire dans le cerveau et sont impliquées dans les processus de démyélinisation et de remyélinisation. Dans ce travail, nous avons étudié les réactions inflammatoires accompagnant la démyélinisation et leurs conséquences sur la remyélinisation. Dans ce but, trois différents traitements démyélinisants ont été appliqués sur des cultures en agrégats de télencéphales de rats, à savoir (i) la lysophosphatidylcholine, (ii) l'interféron-γ (IFN-γ) combiné avec du lipopolysaccharide (LPS), et (iii) des anticorps dirigés contre la MOG (myelin oligodendrocyte glycoprotein) en présence de complément. Nous avons montré que ces traitements induisent différents types de démyélinisation, de réponses inflammatoires et d'effets secondaires sur les neurones. Nous avons ensuite examiné les effets de l'atténuation de la réponse inflammatoire sur la démyélinisation et la remyélinisation, en utilisant la minocycline, un antibiotique bloquant la réactivité microgiale, et le GW 5501516, un agoniste de PPAR-β (peroxisome proliferator-activated receptor-β). Nous avons montré que la minocycline prévient l'activation microgliale induite par le traitement avec l'IFN-γ et le LPS, mais qu'elle ne protège pas de la démyélinisation. Néanmoins, elle induit une remyélinisation, probablement en favorisant la maturation d'oligodendrocytes immatures. Le GW 501516 diminue l'expression de l'IFN-γ après une démyélinisation induite par les anticorps anti-MOG, mais il ne prévient pas la démyélinisation et ne favorise pas la remyélinisation. Ces résultats indiquent que la démyélinisation induite par le traitement avec l'IFN-γ et le LPS n'est pas une conséquence directe de l'activation microgliale, et que l'augmentation de l'expression de l'IFN-γ ne participe pas à la démyélinisation induite par les anticorps anti-MOG. Ces résultats suggèrent que l'atténuation de l'activation microgliale est bénéfique pour la remyélinisation

Role of hexagonal columnar mesophases in polymer crystallization (the case of poly(di-n-alkylsiloxanes))

Comprendre les différentes étapes de la formation des cristaux de polymères au niveau moléculaire représente un des problèmes majeurs dans le domaine de la physique des polymères. Il n'est pas clairement établi si la transition de l'état isotrope, où les chaînes sont enchevêtrées, à une structure semi-cristalline est accompagnée par la présence de phases métastables intermédiaires. Dans ce travail, nous proposons l'étude du processus de cristallisation de polymères qui possèdent une phase cristal-liquide stable thermodynamiquement impliquant l'arrangement des chaînes polymères. En variant les conditions de cristallisation des polymères, cette pré-organisation peut-être activée ou désactivée, permettant d'évaluer les conséquences sur le processus de cristallisation et la morphologie résultante. Les études ont porté sur le poly(di-n-éthylsiloxane), et le poly(di-n-propylsiloxane), en masse et en film mince (épaisseur < 1 m) en utilisant diverses techniques donnant des informations dans les espaces réel et réciproque.Understanding the stages of formation of polymer crystals at the molecular level represents one of the long-standing problems in the field of polymer crystallization. Yet, it is not clear whether the transition from isotropie entangled polymer melt to a partly disentagled semicrystalline structure is accompanied by the presence of intermediate metastable phases. In the present work, we have undertaken a study of the crystallization process of poyymers that do exhibit a thermodynamically stable liquid crystalline phase involving ordering of the chain backbones. By varying the conditions of polymer crystallization or the sample thermal history, such chain preordering could be either activated or deactivated, which allowed evaluating its consequences on the crystallization process and resulting morphology. The studies were performed on bulk and thin film (thickness < 1 ltm) of poly(di-n-ethylsiloxane) and poly(din-propylsiloxane) using a battery of experimental techniques operational in direct and reciprocal space.MULHOUSE-SCD Sciences (682242102) / SudocSudocFranceF

Minocycline promotes remyelination in aggregating rat brain cell cultures after interferon-γ plus lipopolysaccharide-induced demyelination.

Minocycline has been shown to inhibit microglia reactivity, and to decrease the severity and progression of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. It remained to be examined whether minocycline was also able to promote remyelination. In the present study, myelinating aggregating brain cell cultures were used as a model to study the effects of minocycline on microglial reactivity, demyelination, and remyelination. Cultures were treated simultaneously with two inflammatory agents, interferon-γ (IFN-γ) and lipopolysaccharide (LPS), which caused an inflammatory response accompanied by demyelination. The inflammatory response was characterized by microglial reactivity, upregulation of inflammatory cytokines and iNOS, and increased phophorylation of P38 and P44/42 mitogen activated protein (MAP) kinases. Minocycline inhibited microglial reactivity, and attenuated the increased phophorylation of P38 and P44/42 MAP kinases. Demyelination, determined by a decrease in myelin basic protein (MBP) content and immunoreactivity 48 h after the treatment with the inflammatory agents, was not prevented by minocycline. However, 1 week after demyelination was assessed, the MBP content was restored in presence of minocycline, indicating that remyelination was promoted. Concomitantly, in cultures treated with minocycline, the markers of oligodendrocyte precursors cells (OPCs) and immature oligodendrocytes NG2 and O4, respectively, were decreased compared to cultures treated with the inflammatory agents only. These results suggest that minocycline attenuates microglial reactivity and favors remyelination by enhancing the differentiation of OPCs and immature oligodendrocytes