1
|
1409Use of phenomapping to determine response of treatment by sacubitril/valsartan in patients with heart failure with reduced ejection fraction. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Treatment by sacubitril/valsartan decreases mortality, improves KCCQ score and ejection fraction in patients with heart failure with reduced ejection fraction (HF REF), but there is currently no data to predict response to treatment.
Purpose
The purpose of our work was to assess whether unbiased clustering analysis, using dense phenotypic data, could identify phenotypically distinct HF-REF subtypes with good or no response after 6 months of sacubitril/valsartan administration.
Methods
A total of 78 patients in NYHA functional class 2–3 and treated by ACE inhibitor or AAR2, were prospectively assigned to equimolar sacubitril/valsartan replacement. We collected demographic, clinical, biological and imaging continuous variables. Phenotypic domains were imputed with 5 eigenvectors for missing value, then filtered if the Pearson correlation coefficient was >0.6 and standardized to mean±SD of 0±1. Thereafter, we used agglomerative hierarchical clustering for grouping phenotypic variables and patients, then generate a heat map (figure 1). Subsequently, participants were categorized using Penalized Model-Based Clustering. P<0,05 was considered significant.
Results
Mean age was 60.4±13.4 yo and 79.0% patients were males. Mean ejection fraction was 29.3±7.0%. Overall, 16 phenotypic domains were isolated (figure 1) and 3 phenogroups were identified (Table 1). Phenogroup 1 was remarkable by isolated left ventricular involvement (LVTDD 64.3±5.9mm vs 73.9±8.7 in group 2 and 63.8±5.7 in group3, p<0.001) with moderate diastolic dysfunction (DD), no mitral regurgitation (MR) and no pulmonary hypertension (PH). Phenogroups 2 and 3 corresponded to patients with severe PH (TRMV: 2.93±0.47m/s in group 2 and 3.15±0.61m/s in groupe 3 vs 2.16±0.32m/s in group 1), related to severe DD (phenogroup 2) or MR (phenogroup 3). In both phenogroups, the left atrium was significantly enlarged and the right ventricle was remodeled, compared with phenogroup 1. Despite more severe remodeling and more compromised hemodynamic in phenogroups 2 and 3, the echocardiographic response to sacubitril/valsartan was comparable in all groups with similar improvement of EF and reduction of cardiac chambers dimensions (response of treatment, defined by improvement of FE +15% and/or decreased of indexed left ventricule diastolic volume −15% = group 2: 22 (76%); group 3: 18 (60%); group 1: 9 (50%); p=0.17; OR group 2 vs 1: OR=3.14; IC95% [0.9–11.03]; p=0.074; OR group 3 vs 1: OR=1.5; IC95% [0.46–4.87]; p=0.5)). The clinical response was even better in phenogroups 2 and 3 (Group 2: 19 (66%); group 3: 21 (78%) vs group 1: 9 (50%); p=0.05).
Heat map
Conclusion
HF-REF patients with severe diastolic dysfunction, significant mitral regurgitation and elevated pulmonary hypertension by echocardiographic had similar reverse remodeling but better clinical improvement than patients with isolated left ventricular systolic dysfunction.
Collapse
|
2
|
Improvement of diastolic function in patients with heart failure and reduced ejection fraction treated by sacubitril/valsartan. ARCHIVES OF CARDIOVASCULAR DISEASES SUPPLEMENTS 2019. [DOI: 10.1016/j.acvdsp.2019.02.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
3
|
Progressive methylation of POU5F1 regulatory regions during blastocyst development. Reproduction 2018; 156:145-161. [PMID: 29866767 DOI: 10.1530/rep-17-0689] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 06/01/2018] [Indexed: 01/14/2023]
Abstract
The POU5F1 gene encodes one of the 'core' transcription factors necessary to establish and maintain pluripotency in mammals. Its function depends on its precise level of expression, so its transcription has to be tightly regulated. To date, few conserved functional elements have been identified in its 5' regulatory region: a distal and a proximal enhancer, and a minimal promoter, epigenetic modifications of which interfere with POU5F1 expression and function in in vitro-derived cell lines. Also, its permanent inactivation in differentiated cells depends on de novo methylation of its promoter. However, little is known about the epigenetic regulation of POU5F1 expression in the embryo itself. We used the rabbit blastocyst as a model to analyze the methylation dynamics of the POU5F1 5' upstream region, relative to its regulated expression in different compartments of the blastocyst over a 2-day period of development. We evidenced progressive methylation of the 5' regulatory region and the first exon accompanying differentiation and the gradual repression of POU5F1 Methylation started in the early trophectoderm before complete transcriptional inactivation. Interestingly, the distal enhancer, which is known to be active in naïve pluripotent cells only, retained a very low level of methylation in primed pluripotent epiblasts and remained less methylated in differentiated compartments than the proximal enhancer. This detailed study identified CpGs with the greatest variations in methylation, as well as groups of CpGs showing a highly correlated behavior, during differentiation. Moreover, our findings evidenced few CpGs with very specific behavior during this period of development.
Collapse
|
4
|
Long-term stability of dexamethasone and alizapride or ondansetron in sodium chloride 0.9% polyolefin bag at 5±3°C. ANNALES PHARMACEUTIQUES FRANÇAISES 2016; 75:30-39. [PMID: 27634586 DOI: 10.1016/j.pharma.2016.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/28/2016] [Accepted: 08/09/2016] [Indexed: 11/16/2022]
Abstract
INTRODUCTION The aim of the study was to investigate the long-term stability of dexamethasone 10mg associated with alizapride 100mg or ondansetron 8mg in 100mL of 0.9% sodium chloride solution stored at 5±3°C. METHOD Solutions of 0.9% sodium chloride 100mL in polyolefin bags (n=5) containing approximately dexamethasone (DEX) 10mg associated with alizapride (ALI) 100mg or ondansetron (OND) 8mg were prepared under aseptic conditions and stored about 30 days at 5±3°C. ALI, DEX and OND concentrations were measured by high-performance liquid chromatography (HPLC). Optic density measurement at different wavelengths, pH measurement and optic microscope observations were performed periodically during the storage. A forced degradation test with HCL 5M and NaOH 5M before and after heating at 100°C was also performed. Solutions were considered stable if the 95% one-sided lower confidence limit of the concentration remains superior to 90% of the initial concentration or 95% of the initial concentration when any signs of physical instability exist as recently recommend. RESULTS The calibration was linear over the following range from 20 to 1.25mg/100mL for DEX, from 200 to 12.5mg/100mL for ALI and from 20 to 1.25mg/100mL for OND with a calculated correlation coefficient (r2) of 0.998, 0.999 and 0.999, respectively. The inter- and intra-assay precision was below 10% for both mixtures. All formulations were physically stable during the storage. The lower confidence limit of the concentration for these solutions remains superior to 90% of the initial concentration at this date as recommended by the Food and Drug Administration (FDA) until 30 days. CONCLUSION The HPLC method is specific and reproducible and can easily be adopted for monitoring the quality control in the production of DEX-ALI and DEX-OND bags. Solutions of DEX-ALI and DEX-OND were physically and chemically stable for 30 days in polyolefin bags stored at 5±3°C and could therefore be prepared in advance.
Collapse
|
5
|
Long-term stability of ketamine hydrochloride 50mg/ml injection in 3ml syringes. ANNALES PHARMACEUTIQUES FRANÇAISES 2016; 74:283-7. [DOI: 10.1016/j.pharma.2016.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/10/2016] [Accepted: 03/16/2016] [Indexed: 10/21/2022]
|
6
|
PP-017 The physical stability of injectable drugs must be proved to ensure patient safety. Eur J Hosp Pharm 2016. [DOI: 10.1136/ejhpharm-2016-000875.456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
7
|
PP-016 Long term stability of a generic product of piperacilline/tazobactam in glucose 5% infusion polyolefin bags at 5°c ± 3°c after microwave freeze–thaw treatment. Eur J Hosp Pharm 2016. [DOI: 10.1136/ejhpharm-2016-000875.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
8
|
[Stability of amiodarone hydrochloride in intravenous fluids with 5% glucose]. JOURNAL DE PHARMACIE DE BELGIQUE 2016:24-25. [PMID: 30281220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
|
9
|
Microwave freeze-thaw technique of injectable drugs. A review from 1980 to 2014. ANNALES PHARMACEUTIQUES FRANÇAISES 2015; 73:436-41. [DOI: 10.1016/j.pharma.2015.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/20/2015] [Accepted: 04/22/2015] [Indexed: 11/17/2022]
|
10
|
[The long-term chemical stability of injectable drugs reconstituted in Hospital Pharmacy]. JOURNAL DE PHARMACIE DE BELGIQUE 2015:36-44. [PMID: 26513834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
BACKGROUND Other injectable preparations than parenteral nutrition admixture and injectable cytotoxic drugs could be prepared by Centralised IntraVenous Admixture Service (CIVAS) if the Long-term stability of the drugs is known. However, this information is not always available. PURPOSE To develop a program of chemical drug stability analysis in collaboration between Hospital Pharmacy, Medical Laboratory and Scientific Support Unit to determine the long-term stability of largely used injectable anti-infectious and non-anti-infectious drugs. MATERIAL AND METHODS After a setup of the High Performance Liquid Chromatography (HPLCI method, 28 drugs were reconstituted in laminar air flow hood, 17 of them stored directly at 5 +/- 3 degrees C and 19 stored in the freezer at -20 degrees C, thawed by microwave following a standardised procedure and stored at 5 +/- 3 degrees C before use. Concentration stability was evaluated by regression analysis. RESULTS For each drug, long-term stability has varied from 11 days to 180 days. The freeze-thaw treatment by microwave may enhance the stability (from 30 to 120 days) and allow batch-scale production of intravenous drugs, less expensive in term of manpower and sterile device than a drug reconstitution at the ward. The results were published by 55 posters in international congress and by 36 publications in national and international pharmaceutical journals. CONCLUSIONS Our findings contribute to enhance the scale of drugs that may be take on by a CIVAS.
Collapse
|
11
|
[Physical compatibility of a mixture of alizapride and dexamethasone in flexible infusion bags of 100 ml of 0.9% NaCl]. JOURNAL DE PHARMACIE DE BELGIQUE 2015:38-39. [PMID: 26466508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
|
12
|
Long-term stability of acyclovir in 0.9% NaCl infusion polyolefin bags at 5±3°C after freeze-thaw treatment: A generic product versus the brand name. ANNALES PHARMACEUTIQUES FRANÇAISES 2015; 73:108-13. [DOI: 10.1016/j.pharma.2014.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/10/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
|
13
|
PP-006 Microwave freeze-thaw treatment of injectable drugs: a review of the literature from 1980 to 2014. Eur J Hosp Pharm 2015. [DOI: 10.1136/ejhpharm-2015-000639.286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
14
|
Long-term stability of morphine hydrochloride in 0.9% NaCl infusion polyolefin bags after freeze-thaw treatment and in polypropylene syringes at 5 degrees C + 3 degrees C. INTERNATIONAL JOURNAL OF PHARMACEUTICAL COMPOUNDING 2014; 18:78-82. [PMID: 24881344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The aim of this study was to investigate the long-term stability of morphine hydrochloride in 0.9% NaCI infusion polyolefin bags and polypropylene syringes after storage at 5 degrees C + 3 degrees C and to evaluate the influence of initial freezing and microwave thawing on this stability. Ten polyolefin bags and five polypropylene syringes containing 100 mL of 1 mg/mL of morphine hydrochloride solution in 0.9% NaCI were prepared under aseptic conditions. Five polyolefin bags were frozen at -20 degrees C for 90 days before storage. Immediately after the preparation and after thawing, 2 mL of each bag were withdrawn for the initial concentration measurements. All polyolefin bags and polypropylene syringes were then refrigerated at 5 degrees C + 3 degrees C for 58 days during which the morphine concentrations were measured periodically by high-performance liquid chromatography using a reversed-phase column, naloxone as internal standard, a mobile phase consisting of 5% acetonitrile and 95% of KH2PO4 buffer (pH 3.50), and detection with diode array detector at 254 nm. Visual and microscopic observations and spectrophotometric and pH measurements were also performed. Solutions were considered stable if the concentration remained superior to 90% of the initial concentration. The degradation products peaks were not quantitatively significant and were resolved from the native drug. Polyolefin bag and polypropylene syringe solutions were stable when stored at 5 degrees C + 3 degrees C during these 58 days. No color change or precipitation in the solutions was observed. The physical stability was confirmed by visual, microscopic, and spectrophotometric inspection. There was no significant change in pH during storage. Freezing and microwave thawing didn't influence the infusion stability. Morphine hydrochloride infusions may be prepared in advance by centralized intravenous additive service, frozen in polyolefin bags, and microwave thawed before storage under refrigeration until 58 days either in polyolefin bags or polypropylene syringes. Such treatment could improve safety and management.
Collapse
|
15
|
TCH-036 Results of a Systematic Long-Term Stability Study For Ready-To-Use Injectable Drugs Produced by a Centralized Intravenous Admixture Service. Eur J Hosp Pharm 2013. [DOI: 10.1136/ejhpharm-2013-000276.227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
16
|
Generation of rabbit pluripotent stem cell lines. Theriogenology 2012; 78:1774-86. [DOI: 10.1016/j.theriogenology.2012.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 06/09/2012] [Accepted: 06/10/2012] [Indexed: 12/20/2022]
|
17
|
Long-term stability of morphine HCl in 0.9% NaCl infusion. Eur J Hosp Pharm 2012. [DOI: 10.1136/ejhpharm-2012-000074.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
18
|
The effects of FSH and of testosterone on the completion of meiosis and the very early steps of spermiogenesis of the rat: an in vitro study. J Mol Endocrinol 2004; 33:729-42. [PMID: 15591031 DOI: 10.1677/jme.1.01493] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The role of FSH and of testosterone in spermatogenesis has been a matter of controversy. In the present study, we addressed the involvement of these hormones in the regulation of the completion of meiosis of male rats under in vitro conditions. In the first series of experiments, middle/late pachytene spermatocytes were cocultured with Sertoli cells for 2 weeks in the absence or presence of FSH and/or testosterone. Treatment with both FSH and testosterone reduced slightly the percentage of apoptotic germinal cells in the cultures. Moreover, the number of round spermatids formed in vitro was enhanced by FSH or testosterone when compared with control cultures. Neither hormone influenced the half-life of round spermatids under the present culture conditions. The amounts of TP1 mRNAs in FSH- or FSH plus testosterone-treated cultures were higher than those of controls. In another series of experiments, round spermatids were incubated for 24 h in media conditioned by Sertoli cells cultured in the absence or presence of FSH and/or testosterone. TP1 mRNA contents of round spermatids incubated in media from Sertoli cells cultured in the presence of FSH and/or testosterone were two- to threefold higher than those of spermatids incubated in media from Sertoli cells cultured without hormones. These results indicate that FSH and testosterone have positive and somewhat overlapping effects on the meiotic divisions and the post-meiotic expression of a germ cell-specific gene, effects which cannot be related solely to their ability to reduce germinal cell apoptosis. Use of this culture system should help to test the effect of any hormone or factor on those steps in order to understand better their regulation.
Collapse
|
19
|
Developmental changes in cyclin B1 and cyclin-dependent kinase 1 (CDK1) levels in the different populations of spermatogenic cells of the post-natal rat testis. Eur J Cell Biol 2000; 79:816-23. [PMID: 11139145 DOI: 10.1078/0171-9335-00107] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spermatogenesis is a highly ordered process which requires mitotic and meiotic divisions. In this work, we studied the relative changes in the levels of the two components of the M-phase promoting factor (MPF): the regulatory subunit cyclin B1 (CycB1) and its catalytic subunit cdk1, in spermatogenic cells of rats between 16 and 90 days of life. A multivariate flow cytometry analysis of forward scatter (FSC), side scatter (SSC) and DNA content was used to identify six populations of rat germ cells: spermatogonia with preleptotene spermatocytes, young pachytene spermatocytes, middle to late pachytene spermatocytes, secondary spermatocytes with doublets of round spermatids, round spermatids, and elongated spermatids. For any population studied no significant difference in the relative cellular content of CycB1 or cdk1 proteins between animals of different ages was observed. By contrast, CycB1 and cdk1 levels were different between the different populations of germ cells. CycB1 and cdk1 were rather high in young pachytene spermatocytes and culminated in late spermatocytes, i.e. just before the first meiotic division. The relative levels of the two proteins remained high in secondary spermatocytes then decreased in round spermatids at the exit of meiosis. Similar results were obtained by Western-blot analysis of total proteins obtained from lysates of elutriated fractions of spermatocytes and spermatids. MPF activity was assessed in lysates of germ cells from 32-day-old rats or adult animals using p13suc1 agarose and histone H1 as an exogenous substrate. H1 kinase activity was higher in pachytene spermatocytes than in round spermatid fractions from both adult and young rats. These results indicate that the meiotic G2/M transition is associated to high levels of CycB1 and cdk1 leading to high MPF activity irrespective of the age of the animals.
Collapse
|
20
|
Infection of primary cultures of mammary epithelial cells by small ruminant lentiviruses. Vet Res 1999; 30:467-74. [PMID: 10543381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
The caprine arthritis-encephalitis virus (CAEV) and Visna Maedi virus cause persistent infections with long latent periods and induce degenerative and chronic inflammatory lesions of the central nervous system, joints, lungs and udder. Monocyte/macrophage lineage is the main target cell for CAEV and Visna Maedi virus but we speculate that mammary epithelial cells may also be infected. Primary cultures of milk cells, mammary tissues of experimentally and naturally infected goats and ewes were used. Primary cultures of mammary tissue from ewes and goats were infected with the CAEV Cork strain. The lentiviral infection of the primary culture was demonstrated by a typical cytopathic effect in mammary epithelial cells and the presence of an infectious virus in coculture with permissive fibroblasts. To identify the epithelial cells in explants and demonstrate the antigenic expression of CAEV, primary cultures were immunostained with polyclonal anti-keratin and monoclonal anti-CAEV p30. Colocalisation studies under a UV fluorescence microscope and by epifluorescence microscopy showed the expression of specific viral antigens in mammary epithelial cells from the eight animals used. Infected mammary epithelial cells may act as a reservoir for the virus which may play an important role in the virus dissemination and in the pathogenesis of the mammary lentiviral disease.
Collapse
|
21
|
|
22
|
Functional domains in the spike protein of transmissible gastroenteritis virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 380:299-304. [PMID: 8830497 DOI: 10.1007/978-1-4615-1899-0_48] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The coronavirus spike protein S is assumed to mediate essential biological functions, including recognition of target cells. Earlier studies from our and other groups identified two regions of the TGEV S (220K) protein possibly implicated in such functions. The first of these corresponds to the 224 amino acid N-terminal region which is deleted in PRCV, the respiratory variant of TGEV. We have examined the pathogenicity for the newborn piglet of a series of neutralization escape mutants encoding an S protein mutated in this region. Several amino acid changes were correlated with a dramatic loss of enterovirulence, thus indicating that crucial determinants are associated with this domain of S. The second region of potential relevance is the major neutralization domain. Baculovirus-vectored expression of 150 to 220 amino acid-long stretches encompassing this region, which is encoded by both TGEV and PRCV, was performed. The resultant recombinant proteins were shown to react with the cognate antibodies and to bind APN specifically, thus localizing the receptor-binding site on the S primary structure. Altogether these data lend support to the view that a domain of S protein structurally distinct from the receptor binding site is required for the virus to express its enteric tropism.
Collapse
|
23
|
Major receptor-binding and neutralization determinants are located within the same domain of the transmissible gastroenteritis virus (coronavirus) spike protein. J Virol 1994; 68:8008-16. [PMID: 7525985 PMCID: PMC237264 DOI: 10.1128/jvi.68.12.8008-8016.1994] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The spike glycoprotein (S) of coronavirus, the major target for virus-neutralizing antibodies, is assumed to mediate the attachment of virions to the host cell. A 26-kilodalton fragment proteolytically cleaved from transmissible gastroenteritis virus (TGEV) S protein was previously shown to bear two adjacent antigenic sites, A and B, both defined by high-titer neutralizing antibodies. Recombinant baculoviruses expressing C-terminal truncations of the 26-kilodalton region were used to localize functionally important determinants in the S protein primary structure. Two overlapping 223- and 150-amino-acid-long products with serine 506 as a common N terminus expressed all of the site A and B epitopes and induced virus-binding antibodies. Coexpression of one of these truncated protein S derivatives with aminopeptidase N (APN), a cell surface molecule acting as a receptor for TGEV, led to the formation of a complex which could be immunoprecipitated by anti-S antibodies. These data provide evidence that major neutralization-mediating and receptor-binding determinants reside together within a domain of the S protein which behaves like an independent module. In spite of their ability to prevent S-APN interaction, the neutralizing antibodies appeared to recognize a preformed complex, thus indicating that antibody- and receptor-binding determinants should be essentially distinct. Together these findings bring new insight into the molecular mechanism of TGEV neutralization.
Collapse
|
24
|
Abstract
The coding potential of the open reading frame ORF4 (82 amino acids) of transmissible gastroenteritis virus (TGEV) has been confirmed by expression using a baculovirus vector. Five monoclonal antibodies (MAbs) raised against the 10K recombinant product immunoprecipitated a polypeptide of a similar size in TGEV-infected cells. Immunofluorescence assays performed both on insect and mammalian cells revealed that ORF4 was a membrane-associated protein, a finding consistent with the prediction of a membrane-spanning segment in ORF4 sequence. Two epitopes were localized within the last 21 C-terminal residues of the sequence through peptide scanning and analysis of the reactivity of a truncated ORF4 recombinant protein. Since the relevant MAbs were found to induce a cell surface fluorescence, these data suggest that ORF4 may be an integral membrane protein having a Cexo-Nendo orientation. Anti-ORF4 MAbs were also used to show that ORF4 polypeptide may be detected in TGEV virion preparations, with an estimated number of 20 molecules incorporated per particle. Comparison of amino acid sequence data provided strong evidence that other coronaviruses encode a polypeptide homologous to TGEV ORF4. Our results led us to propose that ORF4 represents a novel minor structural polypeptide, tentatively designated SM (small membrane protein).
Collapse
|
25
|
Processing and antigenicity of entire and anchor-free spike glycoprotein S of coronavirus TGEV expressed by recombinant baculovirus. Virology 1991; 185:732-40. [PMID: 1660201 PMCID: PMC7131376 DOI: 10.1016/0042-6822(91)90544-l] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The S gene of transmissible gastroenteritis virus (TGEV) was inserted into the genome of Autographa californica nuclear polyhedrosis virus (AcNPV) using the transfer plasmid pVL941. Infection of Sf9 insect cells with the recombinant virus resulted in the synthesis of a 175K polypeptide which was able to trimerize and was transported to the cell surface as is the authentic TGEV S protein. Despite the lack of complete carbohydrate processing, the recombinant S protein exhibited antigenic properties similar to TGEV S and induced high levels of neutralizing antibodies in immunized rats. Engineering a deletion (70 amino acids) into the carboxy-terminus containing the membrane anchor of the polypeptide allowed its secretion. The oligomerization process and the antigenic profile of the anchor-free S protein were shown to be partially altered.
Collapse
|
26
|
Abstract
The causative agent (TGEV) of porcine transmissible gastroenteritis belongs to the Coronaviridae, a family of enveloped viruses with a positive, single-stranded RNA genome. Important progress has recently been made concerning the molecular biology of TGEV. The research work of our group has been focused on two main aspects: genome structure and functional domains of the envelope proteins. TGEV genomic RNA is organised into seven regions. The sequence of six of them, i.e. the 3' most 8300 nucleotides, has been established from cDNA clones. Three genes encoding the structural proteins, the peplomer protein E2, the transmembrane protein E1 and the nucleoprotein, have been identified. Additional open reading frames allowed for the prediction of four non-structural polypeptides, the role of which remains to be discovered. The remaining part of the genome (estimated length 20 kb) is thought to encode the polymerase. Expression of TGEV genes involves the production of six subgenomic mRNAs, which together with the virion RNA, form a 3' terminal nested set. The peplomer glycoprotein E2 (220 kDa) is 1431 residues long and highly glycosylated. Several domains were identified, including a C-terminal anchoring region and at least four major antigenic sites, which cluster in the amino half part of the molecule. Two sites containing most of the critical neutralisation determinants are highly conserved among TGEV strains. The glycoprotein E1 (29kDa) is mostly embedded in the membrane and plays a crucial role in the virion architecture. However, a short N-terminal domain protruding out of the particle mediates complement-dependent neutralisation, and induces alpha interferon synthesis, likely through a direct interaction with the lymphocyte membrane.
Collapse
|
27
|
Four major antigenic sites of the coronavirus transmissible gastroenteritis virus are located on the amino-terminal half of spike glycoprotein S. J Gen Virol 1990; 71 ( Pt 6):1313-23. [PMID: 1693663 DOI: 10.1099/0022-1317-71-6-1313] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Four major antigenic sites have been delineated on the spike protein (S) of the porcine enteric coronavirus transmissible gastroenteritis virus (TGEV) in previous topological studies using monoclonal antibodies (MAbs). Correlation of these sites with the physical structure of the protein was achieved by use of different approaches. Recombinant pEX plasmids directing the synthesis of various fused S polypeptides were constructed. A hybrid protein containing nine S-specific residues (363 to 371) was shown to express site C epitopes. The other sites were localized through study of the antigenic activity of fragments generated by controlled cleavage of the native protein with different endopeptidases. Two identified cleavage products of 26K and 13K, immunoreactive to site A-B- and site D-specific MAbs respectively, could be aligned on the S primary structure according to N-terminal sequence data. This led us to propose that the major neutralization domain A-B is contained in a region of approximately 200 residues with residue 506 as its N boundary. Similarly, site D epitopes should be located within a stretch of 130 residues, starting at 82 residues from the N terminus. Point mutations identified by direct RNA sequencing of neutralization-resistant mutants were consistent with the proposed location of these sites.
Collapse
|
28
|
Enteric coronavirus TGEV: mapping of four major antigenic determinants in the amino half of peplomer protein E 2. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1990; 276:151-7. [PMID: 1715657 DOI: 10.1007/978-1-4684-5823-7_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
29
|
Abstract
Narrow and wide contacts are simulated in this study by considering, respectively, a flat and a sector loaded against a circular disk. In turn, an artificial intermediate film simulates the interfacial film or third body commonly found in dry friction. Normal and tangential stress fields have been determined using a combined photoelastic and interferometric technique. Contact stress distributions are obtained under pure normal load or normal load and torque. Displacements are also calculated at contact from these fields using methods of complex potentials in plane elasticity. Results show that in the cases studied, from a theoretical solid mechanism point of view, the boundary conditions observed are satisfied by considering that there is no relative displacement over the contact zone which is common to two successive load steps.
Collapse
|
30
|
Abstract
A number of lubricants in the well known classes denoted by MIL-L-23699 and MIL-L-7808 specifications and a traction fluid are investigated for their traction behavior in rolling sliding contacts. The experimental traction data are reduced to simple rheological models and the appropriate coefficients are computed. The reduced models are presented in a form which is readily adaptable to the rolling bearing performance simulation computer programs.
Collapse
|
31
|
Abstract
This paper shows that both micropits and spalls occur near pure rolling conditions. The first are initiated at the surface and are related to asperity interaction. The second are well described in the literature and will not be discussed here. A model capable of predicting the mechanical conditions under which micropits are generated is presented. In this model the pressures on asperities are analyzed for given separations of the surfaces; elastic, elasto-plastic, or plastic deformations are deduced. Master curves can be obtained if a pressure index is used, the model requires a comprehensive description of the surface as it calls for the distributions of both profiles height and asperity tip radii of curvature. A new approach was proposed to define the peaks which carries the load in the contact. In this model a peak is defined with respect to the separation of the surfaces. Good correlation between theory and experiment was obtained for materials as different as mild and case hardened steels and with ground and “as received” treated specimen surfaces. The rate of micropit formation which depends necessarily on running-in cannot be predicted at this time. Results however clearly show that when running-in takes place, i.e. when the pressure on asperity tips decreases to a value compatible with elastic deformation, the rate of formation of micropits with time tends to zero and of course fatigue life is increased.
Collapse
|
32
|
Relation Between Wear of Cr.Ni Steels and Debris Transport at High Temperature (950°C). ACTA ACUST UNITED AC 1980. [DOI: 10.1115/1.3251488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Visualization of the friction process of a Cr.Ni Steel pin running on a disk of similar material under nitrogen has shown that a built-up edge (b.u.e.) is gradually formed and eliminated at contact. The construction of the b.u.e. is described. Metallurgical sections of b.u.e. formed under different conditions are analysed and confirm mechanisms suggested by visualization. Both visualization and b.u.e. examinaton point to the importance of flow transport in friction processes.
Collapse
|
33
|
Abstract
Dry bearing tests have been made with a PTFE fibre/glass fibre/phenolic resin composite against stainless steel to examine the influence of time of sliding, counterface roughness and load. The worn surfaces were examined by optical and scanning electron microscopy, energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (ESCA). It is shown that the coefficient of friction and the rate of wear are strongly influenced by the formation of third bodies on both sliding surfaces. The structure and composition of these third bodies depend on the time of sliding and the load, but are independent of counterface roughness. Wear of the PTFE composite appears to occur on several scales, and considerable degradation of PTFE is evident within the third body (transfer film) on the counterface. The significance of these observations to the measured friction and wear rates is discussed.
Collapse
|
34
|
An Attempt to Provide a Unified Treatment of Tribology Through Load Carrying Capacity, Transport, and Continuum Mechanics. ACTA ACUST UNITED AC 1980. [DOI: 10.1115/1.3251457] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper attempts to give a unified treatment of experiments obtained with solid, liquid and boundary lubricants, different plastics, high temperature steels and elastomers. The argument is centered around third body role, load-carrying capacity, transport and continuum mechanics. This study suggests that an extension to general tribology of the continuum approach used in full film lubrication could be profitable.
Collapse
|
35
|
|
36
|
Film Thickness and Effective Viscosity of Some Fire Resistant Fluids in Sliding Point Contacts. ACTA ACUST UNITED AC 1978. [DOI: 10.1115/1.3453174] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Optical film thickness measurements are performed in a pure sliding point contact apparatus for different fire resistant fluids: a water in oil emulsion, a water glycol and a chlorinated diphenyl. Good correlation between theoretical and experimental film thickness results is obtained in the elastohydrodynamic regime for a wide range of pressure viscosity coefficients. No relaxation effects are noted, but the viscosity of the water in oil emulsion is shown to exhibit essentially that of the base oil at high shear rates.
Collapse
|
37
|
Abstract
Two dimensional Fourier transform methods developed by Ling to calculate contact temperatures were applied to the case of a dry bearing operating with a plastic liner. Results show that uncertainties concerning heat distribution along the contact arc cause smaller differences in contact temperatures than some apparently minor design changes. The effect on temperature of various parameters such as liner position, liner thickness, types of motion and speed, and cooling conditions is given. The method proves to be valuable as a guide in the design of dry bearings.
Collapse
|
38
|
Abstract
High speed Couette type flow was studied for small clearance ratios (C/R = 0.0055 and 0.0031). Water flow pattern visualiszations and torque measurements were performed. Results show that Taylor vortices occur at values predicted by theory, they precede turbulence effects and cause an increase in torque which depends on the clearance ratio. Transition between vortex and turbulent flow is gradual and appears to depend on the Taylor number. Taylor vortices can be found in plain bearings.
Collapse
|
39
|
|