69 research outputs found
Recombinant CXCR4/CCR5 hybrid receptors as tools for studies of HIV-1 receptor usage
No full textThe chemokine receptors CCR5 and CXCR4 are required, together with CD4, for the entry of HIV-1 into target cells. CCR5 using HIV-1 dominates during transmission and the asymptomatic phase of infection. During progression, virus phenotypes with the ability to use CXCR4 emerge in about 50% of infected individuals. Individuals continuously harbouring CCR5-restricted isolates still progress to AIDS. Differences among CCR5 using isolates, has been found and an evolution towards an altered mode of CCR5 coreceptor use and a reduced sensitivity to inhibition by natural CCR5 ligands has also been described. With the aim to study interactions of natural ligands and HIV-1 isolates with these chemokine receptors, a set of hybrid CXCR4/CCR5 receptors were constructed. Signalling response to their respective natural ligands, SDF-1 and RANTES were studied and prototypic R5 and X4 isolates (HIV-1BaL and HIV-1IIIB) were tested for their ability to use these chimeric receptors. The results showed that ligands and virus use different receptor epitopes which, in turn, vary between the two receptors. Further, the evolution of primary HIV-1 isolates was studied. A total of 246 sequential primary HIV-1 isolates were studied. Using our chimeric CXCR4/CCR5 receptors, we showed that R5 isolates from immunosuppressed individuals are distinct from those isolated from individuals with higher CD4+ T-cell counts, with regards to coreceptor usage. The analysis also showed that the ability to utilize chimeric receptors correlated inversely with the sensitivity to RANTES inhibition of infection. The R5 isolates used receptor chimeras to various degrees. Based on these results, the R5 viruses could be subdivided into two groups: the R5narrow phenotype and the R5broad phenotype. The R5narrow phenotype is defined as viruses that use wt CCR5 but no chimeric receptors, whereas viruses using at least one chimeric receptor in addition to CCR5, are designated R5broad viruses. The mode of coreceptor use by paired plasma and CSF isolates from HIV-1 infected individuals with varying degree of immunodeficiency and neuropathology were studied. The R5 viral phenotypes predominated both in plasma and in CSF. We were able to identify discordant plasma/CSF wt coreceptor use but also, varying R5 viral phenotypes in the paired isolates within individual patients. There were no characteristic patterns of receptor use that could distinguish CSF from plasma isolates. R5 virus use of chimera FC-2 correlated highly with immunosuppression. Efficient chimeric receptor use also correlated, with an increased resistance to inhibition by the CCR5 antagonist TAK-779. In conclusion, our findings propose that alterations in the mode of CCR5 use may be a key event in R5 virus pathogenesis. We believe that R5 virus ability to utilize these CXCR4/CCR5 chimeric receptors reflects a more flexible and more efficient CCR5 usage, which may include a reduced dependency upon interactions with the N-terminal of the receptor for infection. The findings are important, not only with regards to R5-virus pathogenesis and optimization of emerging treatment with CCR5 antagonists, but also for HIV-infection within the CNS
Recombinant CXCR4/CCR5 hybrid receptors as tools for studies of HIV-1 receptor usage [Elektronisk resurs]
No full textPopular Abstract in Swedish Människan är uppbyggd av ett stort antal celler. För att kroppens olika organ ska kunna samverka och för att kroppen ska kunna fungera som en helhet, måste de olika cellerna kommunicera med varandra. Cellernas kommunikationssystem är uppbyggt av mottagare, s.k. receptorer, på de olika cellernas yta och signaler som skickas runt mellan cellerna. Receptorerna och signalerna fungerar som nyckel och lås, d.v.s. när rätt signal når rätt receptor så får just den cellen information från andra celler och omgivningen. På det sättet når en viss information bara de celler som behöver just den upplysningen. Olika delar av kroppen dirigeras för att fungera på ett visst sätt, vid ett tillfälle. Signalerna kan exempelvis bestå av luktsignaler, hormoner, ljus som lyser in i ögat eller ämnen som påverkar kroppens immunsystem. De flesta receptorer tillhör en familj som heter GPCR. Man har uppskattat att det finns ungefär 800 olika GPCR-receptorer i vår kropp varav ungefär hälften bearbetar luktsignaler som kommer in via näsan. Ett flertal andra signaler och receptorer gör att vårt immunförsvar samarbetar. Immunförsvaret får signaler om främmande ämnen som kommit in i kroppen, eller från en skada som skett i något av kroppens organ. Med hjälp av olika signaler kan sedan immunsystemet agera för att ta bort ämnet eller för att reparera skadan i kroppen. År 1981 började man lägga märke till att ett flertal människor i världen drabbades av en ny okänd sjukdom som bröt ner immunförsvaret. Dessa tidigare friska människors immunsystem fungerade inte längre och de blev sjuka och dog av olika infektionssjukdomar och cancersjukdomar. År 1983 fann man att viruset HIV (Human immunodeficiency virus) orsakade denna nya sjukdom, AIDS (Acquired immunodeficiency syndrome). Sedan dess har många människor i världen blivit infekterade och avlidit i AIDS. Detta arbete handlar om två GPCR-receptorer, CCR5 och CXCR4, som normalt fungerar i kroppens immunförsvar. 1996 visade det sig att dessa två receptorer utnyttjas av HIV när det tar sig in och infekterar olika celler i kroppen. Utan dessa receptorer på cellytan kan cellerna inte infekteras. Denna nya kunskap ledde till att intresset för hur HIV använder sig av och kommer in i cellerna via dessa receptorer, blev mycket stort. När en person blir infekterad använder HIV nästan alltid den ena receptorn CCR5. Hos personer som är svårt sjuka i AIDS har man kunnat visa att de virus som de har i kroppen då, ofta använder den andra receptorn, CXCR4. Det verkar alltså som att HIV förändras under den tid det tar från att man smittats, tills man är svårt sjuk i AIDS, något som ofta tar många år. I det här arbetet har vi tagit reda på mer om hur det går till när HIV tar sig in i cellerna genom att använda dessa receptorer. För att kunna göra detta tillverkade jag blandreceptorer (hybrider), som består av delar från både CCR5 och den andra receptorn CXCR4. I ett första arbete visade vi att HIV använder receptorerna på andra sätt än immunförsvarets naturliga signalämnen. Resultatet visade att man kan utveckla HIV-läkemedel som blockerar användandet av dessa receptorer utan att störa de naturliga signalerna som överförs via receptorerna. Genom samarbeten med Lunds universitetssjukhus och Sahlgrenska universitets-sjukhuset i Göteborg har vi kunnat ta fram HIV från ett flertal patienter. HIV från smittade, fortfarande relativt friska personer, samt från patienter som är svårt sjuka i AIDS, har isolerats. Med hjälp av de konstgjorda hybridreceptorerna har vi sedan kunnat visa att dessa olika HIV-isolat använder receptorerna på olika sätt för att ta sig in i cellerna. Det sker alltså en utveckling av viruset under sjukdomsprocessen. Viruset förändrar sitt sätt att använda receptorn, CCR5, när personen blir sjukare och det blir också svårare att blockera infektionen med vissa typer av HIV-läkemedel. Vi har dessutom isolerat HIV från hjärnan för att jämföra med HIV som finns i kroppens blodbanor utanför hjärnan. Även här har vi kunnat se skillnader i hur viruset använder CCR5 och att viruset i hjärnan ibland skiljer sig från viruset i blodbanan, hos en och samma person. Detta ökar förståelsen för den speciella AIDS-demens som patienter kan drabbas av. Även i denna studie hittade vi virus med olika känslighet för blockering med läkemedel. Hybridreceptorerna som har använts i de tre studier som avhandlingen bygger på, har visat sig vara mycket bra verktyg för att förstå infektionen och sjukdomsprocessen. Genom att lära sig mer om hur HIV fungerar och tar sig in i den infekterade personens olika celler i kroppen, kan man öka kunskapen om sjukdomen, optimera behandlingen, samt lättare utveckla nya läkemedel mot HIV och sjukdomen AIDS.The chemokine receptors CCR5 and CXCR4 are required, together with CD4, for the entry of HIV-1 into target cells. CCR5 using HIV-1 dominates during transmission and the asymptomatic phase of infection. During progression, virus phenotypes with the ability to use CXCR4 emerge in about 50% of infected individuals. Individuals continuously harbouring CCR5-restricted isolates still progress to AIDS. Differences among CCR5 using isolates, has been found and an evolution towards an altered mode of CCR5 coreceptor use and a reduced sensitivity to inhibition by natural CCR5 ligands has also been described. With the aim to study interactions of natural ligands and HIV-1 isolates with these chemokine receptors, a set of hybrid CXCR4/CCR5 receptors were constructed. Signalling response to their respective natural ligands, SDF-1 and RANTES were studied and prototypic R5 and X4 isolates (HIV-1BaL and HIV-1IIIB) were tested for their ability to use these chimeric receptors. The results showed that ligands and virus use different receptor epitopes which, in turn, vary between the two receptors. Further, the evolution of primary HIV-1 isolates was studied. A total of 246 sequential primary HIV-1 isolates were studied. Using our chimeric CXCR4/CCR5 receptors, we showed that R5 isolates from immunosuppressed individuals are distinct from those isolated from individuals with higher CD4+ T-cell counts, with regards to coreceptor usage. The analysis also showed that the ability to utilize chimeric receptors correlated inversely with the sensitivity to RANTES inhibition of infection. The R5 isolates used receptor chimeras to various degrees. Based on these results, the R5 viruses could be subdivided into two groups: the R5narrow phenotype and the R5broad phenotype. The R5narrow phenotype is defined as viruses that use wt CCR5 but no chimeric receptors, whereas viruses using at least one chimeric receptor in addition to CCR5, are designated R5broad viruses. The mode of coreceptor use by paired plasma and CSF isolates from HIV-1 infected individuals with varying degree of immunodeficiency and neuropathology were studied. The R5 viral phenotypes predominated both in plasma and in CSF. We were able to identify discordant plasma/CSF wt coreceptor use but also, varying R5 viral phenotypes in the paired isolates within individual patients. There were no characteristic patterns of receptor use that could distinguish CSF from plasma isolates. R5 virus use of chimera FC-2 correlated highly with immunosuppression. Efficient chimeric receptor use also correlated, with an increased resistance to inhibition by the CCR5 antagonist TAK-779. In conclusion, our findings propose that alterations in the mode of CCR5 use may be a key event in R5 virus pathogenesis. We believe that R5 virus ability to utilize these CXCR4/CCR5 chimeric receptors reflects a more flexible and more efficient CCR5 usage, which may include a reduced dependency upon interactions with the N-terminal of the receptor for infection. The findings are important, not only with regards to R5-virus pathogenesis and optimization of emerging treatment with CCR5 antagonists, but also for HIV-infection within the CNS
Care of older people in the future : about generations experiences and conceptions
No full textAuthor: Nancy Haglund & Liselotte Ivarsson Title: Care of older people in the future, about generations experiences and conceptions [Translated title]. Assessor: Jan Petersson This study examine generations in three different age–attitudes towards elderly care in the future. Today there is an ongoing debate in Sweden concerning the care of older people. The main focus in the debate is that there is cut down on personnel and resources in the care of the elderly. We have focused on the Kalmar region, since our intention is not to compare with other regions. The study is based on individual experiences and conceptions of the people that participated in this examine, in order to link it to differences and similarities from a generational perspective. To carry out this task, we used a qualitative approach with semi-structured individual interviews. The result is our complied themes from the interviews. The shared beliefs of all participants were that they felt concerned about the factors that can influence the future of their elderly´s care and wellbeing. Key words: Care of older people, generations, differences, similarities
Care of older people in the future : about generations experiences and conceptions
No full textAuthor: Nancy Haglund & Liselotte Ivarsson Title: Care of older people in the future, about generations experiences and conceptions [Translated title]. Assessor: Jan Petersson This study examine generations in three different age–attitudes towards elderly care in the future. Today there is an ongoing debate in Sweden concerning the care of older people. The main focus in the debate is that there is cut down on personnel and resources in the care of the elderly. We have focused on the Kalmar region, since our intention is not to compare with other regions. The study is based on individual experiences and conceptions of the people that participated in this examine, in order to link it to differences and similarities from a generational perspective. To carry out this task, we used a qualitative approach with semi-structured individual interviews. The result is our complied themes from the interviews. The shared beliefs of all participants were that they felt concerned about the factors that can influence the future of their elderly´s care and wellbeing. Key words: Care of older people, generations, differences, similarities
The Impact of Tourism on Curacao's Economy: A Scenario Approach
No full textCuraçao is an autonomous countrywithin the Kingdom of the Netherlands. The governmentwants to support tourism development. However,various development strategies are possible. This articlepresents four scenarios of marketing and investmentstrategies that will affect the number of tourists fromThe Netherlands and North America (USA and Canada)in different ways. A multiplier model was used to calculatethe economic impacts of the four scenarios. Bydoing so, this article shows how the government’s decisionto support particular marketing and investmentstrategies may have certain outcomes for the number ofjobs in Curaçao’s tourism industry
HIV-1 with Multiple CCR5/CXCR4 Chimeric Receptor Use Is Predictive of Immunological Failure in Infected Children
No full textBACKGROUND: HIV-1 R5 viruses are characterized by a large phenotypic variation, that is reflected by the mode of coreceptor use. The ability of R5 HIV-1 to infect target cells expressing chimeric receptors between CCR5 and CXCR4 (R5(broad) viruses), was shown to correlate with disease stage in HIV-1 infected adults. Here, we ask the question whether phenotypic variation of R5 viruses could play a role also in mother-to-child transmission (MTCT) of HIV-1 and pediatric disease progression.
METHODOLOGY/PRINCIPAL FINDINGS: Viral isolates obtained from a total of 59 HIV-1 seropositive women (24 transmitting and 35 non transmitting) and 28 infected newborn children, were used to infect U87.CD4 cells expressing wild type or six different CCR5/CXCR4 chimeric receptors. HIV-1 isolates obtained from newborn infants had predominantly R5(narrow) phenotype (n = 20), but R5(broad) and R5X4 viruses were also found in seven and one case, respectively. The presence of R5(broad) and R5X4 phenotypes correlated significantly with a severe decline of the CD4+ T cells (CDC stage 3) or death within 2 years of age. Forty-three percent of the maternal R5 isolates displayed an R5(broad) phenotype, however, the presence of the R5(broad) virus was not predictive for MTCT of HIV-1. Of interest, while only 1 of 5 mothers with an R5X4 virus transmitted the dualtropic virus, 5 of 6 mothers carrying R5(broad) viruses transmitted viruses with a similar broad chimeric coreceptor usage. Thus, the maternal R5(broad) phenotype was largely preserved during transmission and could be predictive of the phenotype of the newborn's viral variant.
CONCLUSIONS/SIGNIFICANCE: Our results show that R5(broad) viruses are not hampered in transmission. When transmitted, immunological failure occurs earlier than in children infected with HIV-1 of R5(narrow) phenotype. We believe that this finding is of utmost relevance for therapeutic interventions in pediatric HIV-1 infectio
Virus phenotype variability during disease progression of HIV-1 infected children
No full textBackground
HIV-1 infected children display different clinical evolution,
i.e., “fast progression” (FP), “slow progression” (SP)
and “long term non progression” (LTNP). One important
phenotypic trait linked to disease progression is the evolution
of the viral co-receptor use [1], involving a change
from CCR5 to CXCR4 use [2]. However, AIDS symptoms
can appear in absence of X4 viruses. Recently chimeric
receptors between CCR5 and CXCR4 were developed, in
which subsequent parts of CCR5 were replaced with corresponding
parts of CXCR4 [3]. Their use allowed to document
the biological variability of R5 isolates during the
pathogenic process in adults [4].
Aim
To examine the HIV biological variability in children with
different modes of disease progression.
Materials and methods
119 isolates from19 HIV-1 positive children were tested
for their ability to infect U87.CD4+ cells expressing the
wild type receptor CCR5, CXCR4, or one of the 6 chimeric
CCR5/CXCR4 receptors.
Results
Early during infection, all the viruses isolated from 8 SP
children used only wild type CCR5 (called R5narrow). In
one case, this phenotype persisted during disease progression,
whereas in 2 children the virus evolved and was able
to use multiple chimeric receptors (called R5broad), and in
additional 5 children the virus evolved to CXCR4 usage.
Interestengly the FP children, carried close to birth in 2
cases R5narrow virus, in 2 cases R5broad and in one case a
dualtropic R5X4 virus. Virus with R5narrow evolved to
R5broad in one of the 2 children carrying such phenotype.
Both children with R5broad phenotype developed CXCR4
variants during the follow-up.
Evolution was observed also in the LTNP, although followed
from later on in life (>8 years of age): all tested isolates
from 2/6 LTNP remained R5narrow during disease
progression; in one child an evolution from R5narrow to
R5broad was observed whereas in another child the virus
evolved from R5narrow to R5X4. The remaining two children
showed R5broad phenotype during the whole followup.
Conclusions
Our results show that HIV-1 with broad chimeric receptor
use is not hampered in transmission, and is more frequent
close to birth in FP than in SP children. Viruses from LTNP
show a similar phenotypic evolution though at later age
Thaking things further in the SPM journey: Creating the new journey into Strategic Portfolio Managment and successful implementation through new tool design for useability
No full textOrganisations have a lot of trouble with managing their portfolio.The portfolio is the set of projects the company is currently running. The consultancy Jigseye provides tools for that purpose called Strategic Portfolio Management (SPM). They created tools to support organisations in creating that overview and the next step to manage it as a process. Currently, the SPM tools implemented by Jigseye work in practice. They notice that orgnizations still face challenges reaching successful SPM execution. Jigseye wants to improve and extend this set of tools. The goal of my project is to gain an understanding of the SPM tools and design for the new tools with orientation on useability and ease of use. In the research phase, I did extensive user research analysing the SPM tool resulting in user needs for functionality accessibility and the new purpose of creating strategic awareness. Leading to the following vision; the vision is laid out in the form of a journey, leading to new opportunities. This will increase both the effectiveness and efficiency of the SPM tools. Resulting in the New SPM Identity model and New SPM App design with Mobile version; with these tools, designing for a new way of working in the SPM journey leading to new service opportunities for Jigseye.This thesis research is conducted during Covid-19 circumstances 2020-2021 in the Netherlands. The user research covers a unique approach to doing user research during covid-19, personal learnings and a brief study on the influence of covid-19 on SPM and business. Due to company sensitive information, some documentation is left out of this report.Strategic Product Desig
A critical evaluation of (scatterometer-based) ocean surface wind products over sea
No full textBy combining satellite observations and model reanalysis winds, a global data set with higher temporal and spatial resolution ocean surface wind fields can be generated. These superior surface wind fields can have various applications, such as wind forcing of ocean models. The Royal Netherlands Meteorological Institute (KNMI) is responsible for the delivery of two different global data sets of combined surface winds, referred to as IFREMER and ERA5*. IFREMER’s approach focuses on satellite scatterometer observations which are complemented with model reanalysis winds (ERA5). On the other hand, ERA5* is based on ERA5 model reanalysis and corrected with scatterometer observations. The aim of this research is to evaluate global IFREMER and ERA5* surface winds in terms of spatial and temporal characteristics.In order to validate the surface winds of IFREMER and ERA5*, a reference system of true winds is required. For this, quality-controlled wind observations from an independent Chinese scatterometer Haiyang-2B have been used. This comparison study has been carried out for the year 2019 focusing on zonal wind, meridional wind and wind speed. IFREMER and ERA5* wind fields have been collocated in time and space to HY-2B wind observations using a 6-hour and 1-hour window respectively. This methodology was applied to overcome differences between the data sets in grid definition, wind representation, spatial resolution and temporal resolution.On a global scale, IFREMER shows larger average and standard deviation of wind differences with respect to HY-2B than ERA5*, specifically in coastal regions and at higher latitudes. The results of this research suggest that the ERA5* wind product generates more accurate surface ocean winds than IFREMER, except for in the tropics, assuming that HY-2B winds represent the true value. Moreover,at higher wind speeds both global wind products underestimate HY-2B wind, whereby IFREMER already deviates at lower winds than ERA5*. The IFREMER winds showed suspicious satellite tracks and temporal wind inaccuracies, most likely as a result of its 6-hourly resolution. It is recommended that a follow-up investigation is carried out with validation of buoy data in the tropics to investigate the underlying causes of the observed local wind bias.Civil Engineering | Environmental Engineerin
Robots at the construction site: An adjusted business model for construction companies
No full textContext - After the recession of 2008, the real estate market is picking up again. Amongst others due to the urbanisation and the increasing world population the real estate demand is growing. However, the current scarcity of workforce in the construction industry might become a huge issue in the future. In order to deal with the future real estate demand, the conventional construction industry needs to change. Although other industries are gratefully using newly developed technologies such as robots, innovations on the construction site are hardly used.Objective - This thesis aims to investigate how a business model of a Dutch construction company has to change to make on-site robots feasible. This research provides different strategies for construction companies to implement robots for the construction of row-houses, in order to deal with the emerging issues.Methods - This research is divided into three parts. The first section is a literature review providing an overview of currently developed robots, the status of the construction industry and the business models of construction companies. Secondly, an empirical part in which interviews are conducted to find out what the current business model of Dutch construction companies looks like. In addition, a case study in the dairy industry has been conducted as inspiration. In the final part, the operational section, all gained knowledge is combined and formulated as input values for the design of the adjusted business model. This is validated and complemented through a focus group with experts from the construction industry. For this research, the Business Model Canvas of Osterwalder and Pigneur is used as a framework. Results - Three different strategies are designed, based on the current business models of construction companies. These proposed models are adjusted to the input of the chosen robot, the case study in the dairy industry and the outcomes of the focus group. In the business model of the first strategy, the construction job is outsourced to a sub-contractor, who responsible for the operation of the robot. Within this model, minimal adjustments are needed for the construction company itself. However, this is the most expensive way to construct. In the second strategy, the robot is also implemented as key partner in the current business model, in this case not as sub-contractor but as a supplier. The robot is rented by the construction company from an external equipment party. This scenario will require adjustments of the current business model. Although this business model is less costly than the first model, it is still more expansive than currently used construction methods. The last strategy implies the purchase of a robot by the construction company itself. The impact/influence on the business model is shown for a worst and a best-case scenario. This strategy will cause several changes within the current business model, of which the most important is the robot as new key resource. The difference in costs depends on the worst or best scenario. The worst scenario, turned out to be the most expensive one, while the best scenario will just have minimal impact on the costs.Conclusions - Three different strategies are designed with matching business models for the implementation of on-site robots by construction companies. Therefore, it is impossible to develop one generic business models. Hence, the adjusted business models matching to the three possible strategies are based on a merged business model of all the participating construction companies. For each of the strategy, specific adjustments need to be made in the current business model. The first business model, in which the robot will be implemented by a sub-contractor turned out to be the most expensive scenario. Nevertheless, according to the practice, this will be the most promising scenario to start implementing robots. The fact that construction companies take a passive position towards innovations confirms the findings from the literature study that concludes that construction companies are described as traditional and conservative. However, when the urgency for the use construction robots grow, due to an increasing shortage of workforce, it is more likely that the last strategy will be implemented; the purchase of a robot by the construction company itself. This will be the most obvious one, regarding costs, efficiency<br/
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