868 research outputs found
The role of cell-mediated immunity during coronavirus infections in cats : opportunities for therapeutic avenues?
In de kat zijn er twee coronavirussen beschreven: felien enterisch coronavirus (FECV) en feliene infectieuze peritonitis virus (FIPV). FECV, wereldwijd verspreid onder alle katachtigen, veroorzaakt hoogstens een voorbijgaande gastroenteritis en gaat meestal ongemerkt voorbij. Infectie met FIPV leidt meestal tot de dood. De huidige hypothese stelt dat FIPV uit FECV ontstaat door mutatie. Tot op heden concentreren de meeste infectiestudies zich op de humorale immuniteit, die echter beschreven staat als onbeschermend. De sterkte van de cel-gemedieerde immuniteit (CMI) wordt verondersteld als de beslissende factor in FIPV pathogenese. Verrassend genoeg is net over deze CMI gedurende FIPV infecties weinig geweten. Aangezien FIPV uit FECV onstaat door mutatie, is het belangrijk om voor deze beide virussen de CMI te karakteriseren. De focus werd daarom geplaatst op NK cellen, T lymfocyten en regulatorische T cellen (Tregs), die elk cruciaal zijn in respectievelijk de adaptieve, aangeboren en regulatorische immuunresponsen
A value network development model and implications for innovation and production network management
In managing their value network, firms have to balance current and future value concerns and own and network partners' concerns. Firms generate immediate value through manufacturing and selling the current generation of products together with other firms in their production network. Firms generate future value by developing a new product generation with other firms and research institutes in their innovation network. Product innovation and production often take place simultaneously and recurrently. We take the discernible production and innovation activities to occur in co-evolving layers of the same network. We formulate a biplex value network development model that lays out the temporal pattern of production and innovation activities in the value network. We introduce terminology to pinpoint temporal interactions between the innovation and production activities. We study several exemplary complications in the cross-table of inter- and intragenerational interactions versus interactions within and across network layers
A value network development model and implications for innovation and production network management
In managing their value network, firms have to balance current and future value concerns and own and network partners' concerns. Firms generate immediate value through manufacturing and selling the current generation of products together with other firms in their production network. Firms generate future value by developing a new product generation with other firms and research institutes in their innovation network. Product innovation and production often take place simultaneously and recurrently. We take the discernible production and innovation activities to occur in co-evolving layers of the same network. We formulate a biplex value network development model that lays out the temporal pattern of production and innovation activities in the value network. We introduce terminology to pinpoint temporal interactions between the innovation and production activities. We study several exemplary complications in the cross-table of inter- and intragenerational interactions versus interactions within and across network layers
Establishment of feline intestinal epithelial cell cultures for the propagation and study of feline enteric coronaviruses
Feline infectious peritonitis (FIP) is the most feared infectious cause of death in cats, induced by feline infectious peritonitis virus (FIPV). This coronavirus is a virulent mutant of the harmless, ubiquitous feline enteric coronavirus (FECV). To date, feline coronavirus (FCoV) research has been hampered by the lack of susceptible cell lines for the propagation of serotype I FCoVs. In this study, long-term feline intestinal epithelial cell cultures were established from primary ileocytes and colonocytes by simian virus 40 (SV40) T-antigen-and human Telomerase Reverse Transcriptase (hTERT)-induced immortalization. Subsequently, these cultures were evaluated for their usability in FCoV research. Firstly, the replication capacity of the serotype II strains WSU 79-1683 and WSU 79-1146 was studied in the continuous cultures as was done for the primary cultures. In accordance with the results obtained in primary cultures, FCoV WSU 79-1683 still replicated significantly more efficient compared to FCoV WSU 79-1146 in both continuous cultures. In addition, the cultures were inoculated with faecal suspensions from healthy cats and with faecal or tissue suspensions from FIP cats. The cultures were susceptible to infection with different serotype I enteric strains and two of these strains were further propagated. No infection was seen in cultures inoculated with FIPV tissue homogenates. In conclusion, a new reliable model for FCoV investigation and growth of enteric field strains was established. In contrast to FIPV strains, FECVs showed a clear tropism for intestinal epithelial cells, giving an explanation for the observation that FECV is the main pathotype circulating among cats
Dynamics and equilibria under incremental horizontal differentiation on the Salop circle
We study product differentiation on a Salop circle when firms relocate incrementally due to bounded rationality. We prove that, under common assumptions on demand, firms relocate only when two or more firms target the same niche. In any other case, there is no incentive for any firm to relocate incrementally. We prove that all distributions in which firms are sufficiently far apart in product space are unstable Nash equilibria. We prove, in particular, that the classical equidistant distribution is an unstable Nash equilibrium that cannot emerge from another distribution. However, we show that if each firm is engaged in head-on rivalry with one other competitor, the industry converges to an ’equidistantesque’ equilibrium of clusters of rivals
Experimental feline enteric coronavirus infection reveals an aberrant infection pattern and shedding of mutants with impaired infectivity in enterocyte cultures
Feline infectious peritonitis (FIP) results from mutations in the viral genome during a common feline enteric coronavirus (FECV) infection. Since many virological and immunological data on FECV infections are lacking, the present study investigated these missing links during experimental infection of three SPF cats with FECV strain UCD. Two cats showed mild clinical signs, faecal shedding of infectious virus from 4 dpi, a cell-associated viraemia at inconsistent time points from 5 dpi, a highly neutralising antibody response from 9 dpi, and no major abnormalities in leukocyte numbers. Faecal shedding lasted for 28-56 days, but virus shed during this stage was less infectious in enterocyte cultures and affected by mutations. Remarkably, in the other cat neither clinical signs nor acute shedding were seen, but virus was detected in blood cells from 3 dpi, and shedding of non-enterotropic, mutated viruses suddenly occurred from 14 dpi onwards. Neutralising antibodies arose from 21 dpi. Leukocyte numbers were not different compared to the other cats, except for the CD8(+) regulatory T cells. These data indicate that FECV can infect immune cells even in the absence of intestinal replication and raise the hypothesis that the gradual adaptation to these cells can allow non-enterotropic mutants to arise
Bioinformatics : indispensable, yet hidden in plain sight?
BACKGROUND: Bioinformatics has multitudinous identities, organisational alignments and disciplinary links. This variety allows bioinformaticians and bioinformatic work to contribute to much (if not most) of life science research in profound ways. The multitude of bioinformatic work also translates into a multitude of credit-distribution arrangements, apparently dismissing that work. RESULTS: We report on the epistemic and social arrangements that characterise the relationship between bioinformatics and life science. We describe, in sociological terms, the character, power and future of bioinformatic work. The character of bioinformatic work is such that its cultural, institutional and technical structures allow for it to be black-boxed easily. The result is that bioinformatic expertise and contributions travel easily and quickly, yet remain largely uncredited. The power of bioinformatic work is shaped by its dependency on life science work, which combined with the black-boxed character of bioinformatic expertise further contributes to situating bioinformatics on the periphery of the life sciences. Finally, the imagined futures of bioinformatic work suggest that bioinformatics will become ever more indispensable without necessarily becoming more visible, forcing bioinformaticians into difficult professional and career choices. CONCLUSIONS: Bioinformatic expertise and labour is epistemically central but often institutionally peripheral. In part, this is a result of the ways in which the character, power distribution and potential futures of bioinformatics are constituted. However, alternative paths can be imagined
Fractures and other chest wall abnormalities after thoracotomy for esophageal cancer:A retrospective cohort study
Background Chest pain following a thoracotomy for esophageal cancer is frequently reported but poorly understood. This study aimed to (1) determine the prevalence of thoracotomy-related thoracic fractures on postoperative imaging and (2) compare complications, long-term pain, and quality of life in patients with versus without these fractures. Methods This retrospective cohort study enrolled patients with esophageal cancer who underwent a thoracotomy between 2010 and 2020 with pre- and postoperative CTs (<1 and/or >6 months). Disease-free patients were invited for questionnaires on pain and quality of life. Results Of a total of 366 patients, thoracotomy-related rib fractures were seen in 144 (39%) and thoracic transverse process fractures in 4 (2%) patients. Patients with thoracic fractures more often developed complications (89% vs. 74%, p = 0.002), especially pneumonia (51% vs. 39%, p = 0.032). Questionnaires were completed by 77 after a median of 41 (P-25-P(75 )28-91) months. Long-term pain was frequently (63%) reported but was not associated with thoracic fractures (p = 0.637), and neither were quality of life scores. Conclusions Thoracic fractures are prevalent in patients following a thoracotomy for esophageal cancer. These thoracic fractures were associated with an increased risk of postoperative complications, especially pneumonia, but an association with long-term pain or reduced quality of life was not confirmed
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