Identification of a Grotthuss proton hopping mechanism at protonated polyhedral oligomeric silsesquioxane (POSS) - water interface.

The attachment and dissociation of a proton from a water molecule and the proton transfers at solid-liquid interfaces play vital roles in numerous biological, chemical processes and for the development of sustainable functional materials for energy harvesting and conversion applications. Using first-principles computational methodologies, we investigated the protonated forms of polyhedral oligomeric silsesquioxane (POSS-H+) interacting with water clusters (Wn, where n = 1-6) as a model to quantify the proton conducting and localization ability at solid-liquid interfaces. Successive addition of explicit water molecules to POSS-H+ shows that the assistance of at least three water molecules is required to dissociate the proton from POSS with the formation of an Eigen cation (H9O4+), whereas the presence of a fourth water molecule highly favors the formation of a Zundel ion (H5O2+). Reaction pathway and energy barrier analysis reveal that the formation of the Eigen cation requires significantly higher energy than the Zundel features. This confirms that the Zundel ion is destabilized and promptly converts in to Eigen ion at this interface. Moreover, we identified a Grotthuss-type mechanism for the proton transfer through a water chain close to the interface, where symmetrical and unsymmetrical arrangements of water molecules around H+ of protonated POSS-H+ are involved in the conduction of proton through water wires where successive Eigen-to-Zundel and Zundel-to-Eigen transformations are observed in quick succession.

Defects in metal-organic frameworks: a compromise between adsorption and stability?

Defect engineering has arisen as a promising approach to tune and optimise the adsorptive performance of metal-organic frameworks. However, the balance between enhanced adsorption and structural stability remains an open question. Here both CO2 adsorption capacity and mechanical stability are calculated for the zirconium-based UiO-66, which is subject to systematic variations of defect scenarios. Modulator-dependence, defect concentration and heterogeneity are explored in isolation. Mechanical stability is shown to be compromised at high pressures where uptake is enhanced with an increase in defect concentration. Nonetheless this reduction in stability is minimised for reo type defects and defects with trifluoroacetate substitution. Finally, heterogeneity and auxeticity may also play a role in overcoming the compromise between adsorption and stability.

A systematic typology for negative Poisson's ratio materials and the prediction of complete auxeticity in pure silica zeolite JST.

Single crystals can commonly have negative Poisson's ratio in a few directions; however more generalised auxeticity is rarer. We propose a typology to distinguish auxetic materials. We characterise numerous single crystals and demonstrate that partial auxeticity occurs for around 37%. We find average auxeticity to be limited to α-cristobalite and no example of complete auxeticity. We simulate two hundreds pure silica zeolites with empirical potentials and quantum chemistry methods, and for the first time identify complete auxeticity in a zeolite network, JST.

French Otorhinolaryngology Society guidelines for day-case nasal surgery.

OBJECTIVES: The French Otorhinolaryngology Society (SFORL) set up a work group to draw up a consensus document on day-case surgery in four rhinologic procedures: endoscopic middle meatal antrostomy (French National Health Insurance (CCAM) code GBPE001), septoplasty (GAMA007), and reduction of nasal bone fracture using a direct approach (LAEA007) and using a closed technique (LAEP002). MATERIALS AND METHODS: Methodology followed the French Health Authority (HAS) "Methodological Bases for Drawing Up Professional Guidelines by Formalized Consensus" published in January 2006; the method chosen was the short version of the RAND/UCLA Appropriateness Method (without editorial group), as the work group topic was highly specialized, with few experts available. RESULTS: Ahead of any day-case sinonasal surgery, it is recommended that patient eligibility criteria be respected and hemorrhagic risk assessed; preference should be given to short procedures involving little variation in surgery time and minimizing blood-loss, and associated procedures (e.g., septoplasty+turbinectomy) should be avoided. The patient and family should be informed of specific hemorrhagic, orbital and/or neuromeningeal risks, onset of which may preclude discharge home. Uni- or bilateral postoperative nasal packing is not a contraindication to day-case management. CONCLUSION: All four procedures may be performed on a day-case basis. Eligibility criteria should be systematically respected, but hemorrhagic risk, which is very specific to the sinonasal organ, is to be assessed on a case-by-case basis, as it is a major issue in this kind of management for a non-negligible number of patients.

Free energy landscapes for the thermodynamic understanding of adsorption-induced deformations and structural transitions in porous materials.

Soft porous crystals are flexible metal-organic frameworks that respond to physical stimuli such as temperature, pressure, and gas adsorption by large changes in their structure and unit cell volume. While they have attracted a lot of interest, molecular simulation methods that directly couple adsorption and large structural deformations in an efficient manner are still lacking. We propose here a new Monte Carlo simulation method based on non-Boltzmann sampling in (guest loading, volume) space using the Wang-Landau algorithm, and show that it can be used to fully characterize the adsorption properties and the material's response to adsorption at thermodynamic equilibrium. We showcase this new method on a simple model of the MIL-53 family of breathing materials, demonstrating its potential and contrasting it with the pitfalls of direct, Boltzmann simulations. We furthermore propose an explanation for the hysteretic nature of adsorption in terms of free energy barriers between the two metastable host phases.

At least one class I gene in restriction fragment pattern-Y (Rfp-Y), the second MHC gene cluster in the chicken, is transcribed, polymorphic, and shows divergent specialization in antigen binding region.

MHC genes in the chicken are arranged into two genetically independent clusters located on the same chromosome. These are the classical B: system and restriction fragment pattern-Y (Rfp-Y), a second cluster of MHC genes identified recently through DNA hybridization. Because small numbers of MHC class I and class II genes are present in both B: and Rfp-Y, the two clusters might be the result of duplication of an entire chromosomal segment. We subcloned, sequenced, and analyzed the expression of two class I loci mapping to Rfp-Y to determine whether Rfp-Y should be considered either as a second, classical MHC or as a region containing specialized MHC-like genes, such as class Ib genes. The Rfp-Y genes are highly similar to each other (93%) and to classical class Ia genes (73% with chicken B: class I; 49% with HLA-A). One locus is disrupted and unexpressed. The other, YFV, is widely transcribed and polymorphic. Mature YFV protein associated with beta(2)m arrives on the surface of chicken B (RP9) lymphoma cells expressing YFV as an epitope-tagged transgene. Substitutions in the YFV Ag-binding region (ABR) occur at four of the eight highly conserved residues that are essential for binding of peptide-Ag in the class Ia molecules. Therefore, it is unlikely that Ag is bound in the YFV ABR in the manner typical of class Ia molecules. This ABR specialization indicates that even though YFV is polymorphic and widely transcribed, it is, in fact, a class Ib gene, and Rfp-Y is a region containing MHC genes of specialized function.

Interaction of Marek's disease virus and Cryptosporidium baileyi in experimentally infected chickens.

Histocompatible B13/B13 white specific-pathogen-free leghorn chickens were used to investigate the effect of coinfection with Cryptosporidium baileyi and the HPRS 16 strain of Marek's disease virus (MDV) in chickens and to assess the pathogenicity of C. baileyi when MDV is given before or after the parasite. Groups of chickens concurrently infected with C. baileyi orally inoculated at day (D)4 and MDV inoculated at hatching (C4M0 group) or at D8 (C4M8 group) were compared with relevant control groups inoculated with only C. baileyi at D4 (C4 group), only MDV at hatching (M0 group) or at D8 (M8 group), and an uninoculated control group (UC group). The chickens were kept in isolator units until the end of the experiment at D62. Our results showed a considerable synergistic effect in concurrently infected chickens and more severe consequences when chickens received MDV before C. baileyi infection. In fact, except for a slight transitory weakness, the chickens in C4 group remained free of overt clinical signs and there was no mortality. However, coinfection with both pathogens induced more lasting or permanent oocyst shedding. Severe clinical cryptosporidiosis with weakness, anorexia, depression, growth retardation, and chronic and severe respiratory disease causing death occurred in all chickens in the C4M0 group between D12 and D43 and in 67% of the chickens in the C4M8 group between D17 and D57. Eighty-two percent and 33%, respectively, died before the development of specific Marek's disease lesions. Mortality rates were 27% and 33% in the M0 and M8 groups, respectively. The presence of MDV enhanced the establishment of more lasting cryptosporidial infection in the respiratory tract, esophagus, crop, proventriculus, and kidneys (only in C4M0 group) as well as in bursa of Fabricius, ceca, and cloaca. Serologic analysis showed that chickens with chronic cryptosporidiosis in the C4M8 group had an increased level of C. baileyi-specific immunoglobulin A. Our results may explain some cases of mortality in chickens naturally infected with MDV and Cryptosporidium.

Effect of Cryptosporidium baileyi in specific pathogen free chickens vaccinated (CVI988/Rispens) and challenged with HPRS-16 strain of Marek's.

This study was performed to examine the effect of Marek's disease virus (MDV) serotype 1 vaccine (CVI988/Rispens) on the pathogenicity of Cryptosporidium baileyi , and to determine whether C. baileyi infection could prevent the development of vaccinal Marek's disease (MD) immunity in specific pathogen free (SPF) chickens. Sixty-eight SPF homozygous B13 White Leghorn chickens were divided into seven groups. C. baileyi was orally administered at 5 days of age (day 4) in chickens infected with Rispens vaccine at day 0 or at day 8 and challenged with HPRS-16 strain of oncogenic MDV at day 15. Relevant control groups were constituted. The chickens were kept in isolators until the end of the experiment at day 62. The parameters evaluated were clinical signs, kinetics of oocyst shedding, mortality, macroscopic and microscopic lesions, cryptosporidia location in various organs and serum anti- C. baileyi antibodies at days 42 and 62. Our results show that C. baileyi , which is considered to be non-pathogenic when inoculated orally, may become highly pathogenic. It induced severe mortality and developed in organs other than classical target sites when chickens were vaccinated with Rispens vaccine and challenged with the HPRS-16 strain of MDV.However,parasite infection does not prevent the induction of vaccinal immunity for MD. Our results also show that vaccination of B13 chickens at hatching induces higher protection against challenge with HPRS-16 MDV at day 15 than vaccination at day 8.

Renal Cryptosporidiosis (Cryptosporidium baileyi) in specific-pathogen-free chickens experimentally coinfected with Marek's disease virus.

Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.

Intratesticular inoculation of avian leukosis virus (ALV) in chickens--production of neutralizing antibodies and lack of virus shedding into semen.

In order to investigate the possibility of producing transgenic chickens by injection of avian leukosis virus-based vectors into testis, we have analyzed the infection rate of testicular cells following inoculation of Rous-associated virus type 1 (RAV-1) into the gonads of adult and 1-wk-old brown leghorn males. Viroproduction, neutralizing antibody production, and vital DNA presence in testis, blood, muscle, and semen were analyzed at various times after infection. Inoculation of RAV-1 into the gonads of adult males resulted in a low level of viroproduction in testis and blood, followed by the appearance of neutralizing antibody 2 or 3 wk later. Neither viroproduction in semen nor viral DNA presence in sperm were detected even though the infected chickens were found to produce RAV-1 in testis. One week after intratesticular inoculation of 1-wk-old males with RAV-1, a high level of viroproduction was found in blood and testis, and viral DNA was detected in gonadal cells. Further, by 6 wk after inoculation, the production of virus decreased in all tissues, viral DNA could not longer be detected in the testis, and neutralizing antibodies appeared in blood. All together these data show that it is possible to infect testicular cells by direct inoculation of RAV-1 in the testis, and that the immune response of both adult and young chickens seems to reduce this infection. Moreover, no evidence of spermatozoa infection was found; this result suggests that RAV-1 inoculation into testis may not induce genetic transmission of virus, and consequently would not be useful in the production of transgenic chickens.

Intramagnal insemination of hens can eliminate negative influence of lipofectin on fertilising ability of spermatozoa.

1. After intramagnal insemination egg production decreased drastically during the first two days and was equivalent to egg production of hens inseminated intravaginally for the remaining period of collection. 2. After magnal insemination, the fertility of eggs collected during the first week was 36.2% and only 3.6% during the second week. 3. In the case of intramagnal insemination, egg fertility in the first week was 88.1%, in the second week 81.8% and the third week 52.3%. 4. The eggs laid during the first day after intramagnal insemination were 83.3% fertile, indicating that treated spermatozoa fertilised the newly ovulated egg within 20 minutes of ovulation.

Occupational exposure to poultry and prevalence of antibodies against Marek's disease virus and avian leukosis retroviruses.

OBJECTIVES: To compare the prevalence of antibodies against Marek's disease herpes virus (MDV) and against avian leukosis viruses type C (ALV) in groups of workers exposed to poultry and in unexposed groups. METHODS: Antibodies directed against avian viral proteins were detected by enzyme linked immunosorbent assay in 549 subjects. Exposure to chickens was high in two subgroups: farmers on intensive chicken farms and workers at chicken slaughterhouses. One subgroup, traditional farmers on dairy or pig farms with poultry, had moderate exposure to poultry. Another subgroup, farmers and slaughterhouse workers on quail farms, had high exposure to quails. Three subgroups were not exposed to chickens: farmers on dairy or pig farms without poultry, workers at cattle slaughterhouses, and white collar workers. Also, MDV antibodies were tested after serum sample adsorption with chicken antigens in 134 serum samples. RESULTS: The prevalence of antibodies against MDV was significantly higher in the exposed subgroups than in unexposed groups (odds ratio (OR) 6.17; 95% confidence interval (95% CI) 3.91-9.75). No association was found between seroprevalence and age. However, higher prevalence was found among women and was related to duration of exposure to chickens. The concentration of antibodies from a few subjects remained very high after adsorption. Significant differences between the men and women were found for the prevalence of antibodies for ALV but were not related to exposure to chickens. CONCLUSIONS: The prevalence of antibodies against MDV was significantly higher among workers exposed to chickens and was related to sex and duration of exposure. The higher prevalence of antibodies against avian oncogenic viruses found among women compared with men may be induced by differences in exposure or by genetic factors. The meaning of these high titres could be related to the presence of MDV in humans. Because the involvement of animal oncogenic viruses in human cancer is indicated by epidemiological and some experimental studies, the integration of viral DNA in human cells needs to be investigated.

The tetrapeptide AcSDKP, a negative regulator of cell cycle entry, inhibits the proliferation of human and chicken lymphocytes.

The tetrapeptide AcSer-Asp-Lys-Pro (AcSDKP) is a physiological negative regulator of hematopoiesis in mammals. It acts by blocking the cell cycle entry of quiescent stem cells and progenitors. In the present study we report that AcSDKP blocks the proliferation of human as well as chicken lymphocytes. It inhibits by 25 to 40% the polyclonal mitogen- (phytohemagglutinin (PHA), pokeweed mitogen (PWM), or concanavalin A) or mixed lymphocyte reaction-induced proliferation of chicken lymphocytes. A comparable degree of inhibition was observed in human whole blood cultures stimulated by "T" (PHA) or "T and B" (PWM) mitogens. Our results obtained on two phylogenetically distant species show that AcSDKP reduces the lymphocyte proliferation probably by blocking or retarding entry into the cell cycle as previously demonstrated for hematopoietic progenitors and hepatocytes. Therefore, this endogenous, non-species-specific tetrapeptide may be involved in the regulation of immune response.

Influence of chicken genotype on protection against Marek's disease by a herpesvirus of turkeys recombinant expressing the glycoprotein B (gB) of Marek's disease virus.

Two inbred lines of White Leghorn chickens which differ in B-haplotype were immunized at 2 days of age with a thymidine kinase negative (tk-ve) herpesvirus of turkeys (HVT) recombinant expressing the glycoprotein B (gB) gene of Marek's disease virus (MDV) and were challenged 6 days later with 1000 p.f.u. of the highly virulent RB1B strain of MDV. Mock-vaccinated chickens and chickens immunized with a spontaneous tk-ve HVT mutant served as controls. Genetically resistant B21 chickens were protected by immunization with the recombinant as well as by the tk-ve HVT, whereas highly susceptible B13 chickens were partially protected by the recombinant but were not protected by the tk-ve HVT. Rhode Island Red chickens (HPRS RIR), which differ from the White Leghorns at the B locus, were protected by both vaccines but the recombinant conferred a significantly higher level of protection than the tk-ve HVT. The results suggest that the gB gene of MDV serotype 1 has an important role in the induction of protective immunity against highly virulent MDV in genetically susceptible lines of chickens and that vaccinal immunity in White Leghorns might be influenced by the B haplotype.

The tetrapeptide AcSDKP, a physiological inhibitor of normal cell proliferation, reduces the S phase entry of continuous cell lines.

The tetrapeptide AcSer-Asp-Lys-Pro (AcSDKP), a physiological negative regulator of cell proliferation, inhibits the progression of normal quiescent cell to the S phase of the cycle, while it is inactive in the proliferation of permanent cell lines and of freshly isolated leukemic cells. It protects normal hematopoietic stem cells and progenitors from the toxic effects of anticancer drugs. We studied the effects of AcSDKP on the S phase entry of mouse and chicken continuous cell lines MS-K, 3T3, MDCC-PA9, and MDCC-MSB1 lines when they are cultured under these defined conditions. They show that AcSDKP acts on cells previously partially synchronized by culture under conditions of low serum concentrations or serum starvation. Our results demonstrate that AcSDKP reduces the proliferation of these cell of continuous cell lines as it does on hepatocytes or hematopoietic cells in vivo or on freshly isolated cells in vitro, by blocking or retarding their entry into S phase from early G1.

Germline transmission of exogenous genes in chickens using helper-free ecotropic avian leukosis virus-based vectors.

We have used vectors derived from avian leukosis viruses to transduce exogenous genes into early somatic stem cells of chicken embryos. The ecotropic helper cell line, Isolde, was used to generate stocks of NL-B vector carrying the Neo(r) selectable marker and the Escherichia coli lacZ gene. Microinjection of the NL-B vector directly beneath unincubated chicken embryo blastoderms resulted in infection of germline stem cells. One of the 16 male birds hatched (6.25%) from the injected embryos contained vector DNA sequences in its semen. Vector sequences were transmitted to G1 progeny at a frequency of 2.7%. Neo(r) and lacZ genes were transcribed in vitro in chicken embryo fibroblast cultures from transgenic embryos of the G2 progeny.

Somatic and germline chicken chimeras obtained from brown and white Leghorns by transfer of early blastodermal cells.

Stage X blastodermal cells were isolated from freshly laid unincubated Brown Leghorn chicken eggs. Five hundred cells from Stage X Brown Leghorn embryos were injected into the subgerminal cavity of White Leghorn unincubated embryos exposed to 550 rad of gamma irradiation from a cesium-137 source. Of 712 White Leghorn embryos that were irradiated and injected with Brown Leghorn blastodermal cells, 52 (7.3%) survived to hatching. Somatic chimerism was examined in the melanocyte population and erythroid lineage. The presence of brown feathers indicating donor cell contribution to melanocyte pigmentation was observed in 23 (44%) out of the 52 hatched chicks. Analysis of blood DNA was performed using a probe that revealed an endogenous retroviral gag fragment specific for the donor genome. Three out of these 23 chimeric chickens exhibited the gag-specific fragment. To test germline chimerism, chickens that reached sexual maturity were mated with Brown Leghorns. Three somatically chimeric hens produced Brown Leghorn progeny at a rate of 30.7, 9.2, and 2.9% respectively, thus proving donor cell contribution to the germline differentiation. Chimeric chickens obtained after injection of nonirradiated embryos exhibited a lower extent of chimerism at the feather level and did not show any chimerism in the erythroid lineage and the germline, thus demonstrating the value of the use of compromised recipient embryos to produce chimeras in chickens. Nevertheless, the extent of somatic chimerism could not be used to predict the germline chimerism.

Biochemical and functional characterization of an avian homolog of the integrin GPIIb-IIIa present on chicken thrombocytes.

We have analyzed the reactivity of a new mouse monoclonal antibody (mAb), 11C3, which identifies a cell marker detected on the surface of chicken thrombocytes. Tissue distribution studies have shown that only cells of the thrombocytic lineage in blood, spleen, and bone marrow are stained by 11C3. However, it does not react with other species such as quail, mouse, and man. The 11C3 mAb immunoprecipitates an heterodimeric molecule made of two bands with an apparent molecular weight of 112 and 90 kDa under nonreducing conditions and 112 and 26 kDa following reduction. This pattern of migration is similar to the one observed for members of the integrin family of cell adhesion molecules. We have used the previously described mAb AP-2, which is specific for the human platelet integrin GPIIb-IIIa and cross-reacts with chicken thrombocytes. We have shown that it immunoprecipitates two bands with an identical electrophoretic mobility. Cross-inhibition and immunodepletion studies reveal that the two antibodies recognize two different isoforms or two conformational variants of the same molecule. Moreover, our data demonstrate that in contrast with AP-2, 11C3 is a potent inducer of thrombocyte activation measured by cell aggregation, chemiluminescence, or release of [3H]serotonin. It also inhibits the adhesion of thrombin-activated thrombocytes to fibrinogen and, to a lesser degree, to fibronectin, in a dose-dependent manner. Altogether, these results indicate that this antibody identifies the avian homolog of the mammalian platelet integrin and fibrinogen receptor GPIIb-IIIa.